Unveiling the Ecotype driven Virulence Heterogeneity among Major Ecotypes of the Striga hermonthica Population from Ethiopia

Unveiling the Ecotype driven Virulence Heterogeneity among Major Ecotypes of the Striga hermonthica Population from Ethiopia | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Unveiling the Ecotype driven Virulence Heterogeneity among Major Ecotypes of the Striga hermonthica Population from Ethiopia Abiy Legesse Kibebe, Hewan Demissie Degu, Taye Tesema, Habte Neda Chikssa, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7448410/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Striga hermonthica , a root hemiparasitic weed, severely limits sorghum production in Sub Saharan Africa. The use of resistant varieties is a widely adopted strategy for controlling Striga . To develop durable Striga resistant sorghum varieties, this study investigates the interaction effects between host and parasite, as well as the virulence levels of five Ethiopian Striga ecotypes. A pot trial was conducted using seven resistant sorghum varieties, two susceptible checks, and five Ethiopian Striga ecotypes. Valuable data were generated on the interaction effects between sorghum varieties and Striga ecotypes based on three resistance traits: Striga count, Striga length, and dry Striga biomass. The findings revealed variability in sorghum responses to Striga infection, with significant variety by ecotype interaction effects. Notably, the virulence levels of Striga ecotypes varied considerably across sorghum varieties; an ecotype highly virulent to one variety exhibited reduced virulence to another. Similarly, a sorghum variety highly resistant to one ecotype showed moderate or lower resistance to others. The variety Framida generally exhibited high levels of infection, whereas N13 demonstrated stronger resistance. Importantly, sorghum varieties N13 and SRN-39 consistently showed resistance across all tested ecotypes, making them prime candidates for strategic gene pyramiding. This study highlights the presence of interaction effects, which are critical for designing effective breeding strategies in future Striga resistance improvement programs. Furthermore, comprehensive studies on the genetic variability of Ethiopian Striga ecotypes will facilitate the development of durable resistant varieties. Sorghum Striga Ecotype Interaction Virulence Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Sorghum ( Sorghum bicolor ) is one of the most important cereal crops for people in Sub Saharan Africa (SSA), serving as a source of food, feed, nutrients, and various other resources. In this region, its production is severely limited by the most significant biotic constraint: Striga (AATF 2011; Gethi et al. 2005 ). Striga species are obligate root parasites that infest staple crops across the Middle East and parts of Asia (Parker 2012 ). A large proportion of Striga species, over 80%, are found in Africa (Joel et al. 2018). Striga hermonthica is one of the most economically damaging Striga species in several regions of the world, especially in SSA (AATF 2011). The geographical distribution and area coverage of Striga are gradually expanding due to various factors, including declining soil fertility, shorter fallow periods, cultivation shifting to marginal lands, and continuous monoculture practices (Ejeta 2007b ; Emechebe et al. 2004 ). Striga significantly limits sorghum production and may result in total crop loss (Ejeta 2007a ; Muchira et al. 2021 ). The loss has severe economic consequences for farmers, which adversely affect their livelihoods (Emechebe et al. 2004 ). Striga infestation is a major economic concern in Ethiopian sorghum growing regions. This problem is particularly prevalent in Tigray, South and North Wollo, Gonder, Gojam, North Shewa, Gambela, Benishangul Gumuz, and Eastern Hararge (Temesgen 2019 ; Earecho et al. 2024 ). Therefore, addressing Striga infestations through comprehensive efforts is essential to ensure sustainable farming practices and economic stability. Integrated Striga Management (ISM) is now an effective method for reducing the effects of Striga on sorghum production. This method combines resistance genotypes with a variety of management strategies (Mrema et al. 2020 ; Yonli et al. 2012 ). Resistant varieties are now a central component of all ISM approaches in sorghum (Tesso and Ejeta 2011). The advantages of this approach include cost effectiveness, sustainability, environmental friendliness, and suitability for small scale farmers (Mrema et al. 2020 ; Tesso and Ejeta 2011; Yonli et al. 2012 ). This confirms that breeding sorghum for Striga resistance has long term effects on agricultural productivity, particularly in areas where Striga infestation is a major issue (Dossa et al. 2023 ). In Ethiopia, research on Striga resistance or tolerance has achieved some success (AATF 2011). Since the beginning of the sorghum breeding program for Striga resistance, several Striga resistant varieties have been developed, recommended, and incorporated into breeding programs targeting Striga infested regions of Ethiopia. These varieties includes "Berhan," "Gobiye," "Abshir," "Framida," "N13," "SRN-39," "BTx623," and "Tetron." (Abate et al. 2017 ; Ahmed et al. 2024 ; Belay et al. 2021 ; Teka 2014 ; Gobena et al. 2017 ; Kawa et al. 2021 ; Mbuvi et al. 2017 ; Muchira et al. 2021 ; Rodenburg et al. 2005 ; Temesgen 2019 ). However, different infested regions have different levels of success with resistant varieties in reducing the effects of Striga . Due to the high genetic diversity of Striga species, the weak level of host resistance that tends to break down with the infestation of new Striga races (Rispail et al. 2007 ), and the rapid evolution of parasite virulence (Qiu et al. 2022 ), the Striga breeding program and the use of resistant varieties have been complex and ineffective. Striga populations in Ethiopia exhibit a high degree of genetic diversity, with geographical distribution playing a significant role in shaping this diversity (Welsh and Mohamed 2011 ). The extensive genetic diversity of Striga determines its virulence level and the success of host resistance (Haussmann et al. 2001 ). The development of long lasting sorghum varieties resistant to various Striga populations across different ecotypes requires a comprehensive understanding of the polygenic nature of resistance and the associated resistance mechanisms. This includes examining resistance both within and among Striga race structures, as well as understanding the nature of interaction effects between Striga ecotypes and sorghum genotypes and different hosts (Qiu et al. 2022 ; Rispail et al. 2007 ; Scholes and Press 2008 ). In Ethiopia, released resistant varieties demonstrate considerable adaptability, particularly in Striga infested areas. However, there is limited concrete information regarding the genetic variation among sorghum varieties in Striga resistance, the effects of host parasite interactions, and the virulence levels of major Striga ecotypes on different sorghum varieties, especially given the diverse Striga populations across Ethiopian ecotypes (Welsh and Mohamed 2011 ). Moreover, utilizing known improved Striga resistant sorghum varieties enhances our understanding of how sorghum interacts with different Striga ecotypes and the virulence levels of the parasite. This information is critical for advancing future Striga breeding strategies and selecting appropriate varieties for wide Striga ecotypes. Therefore, to assess the genetic variation of Striga resistant sorghum varieties in response to five distinct Ethiopian Striga ecotypes, to determine the virulence levels of Striga ecotypes against seven resistant sorghum varieties, and to investigate the nature of their interaction effects, three Striga resistance traits were collected from a controlled pot experiment. Materials and Methods Experimental location and materials The pot experiment was conducted in 2024 at the Debre Berhan Agricultural Research Center in Debre Berhan. Seeds of seven Striga resistant sorghum varieties and two susceptible checks were obtained from the National Sorghum Research Program at the Melkasa Agricultural Research Center of the Ethiopian Institute of Agricultural Research (Table 1 ). Table 1 List of Striga resistant and susceptible sorghum varieties used in the study Variety Striga resistance reaction References Abshir Resistant (Belay et al. 2021 ; Teka 2014 ) Berhan Resistant (Abate et al. 2017 ; Belay et al. 2021 ; Teka 2014 ) BTx623 Resistant Framida Resistant (Ahmed et al. 2024 ; Muchira et al. 2021 ) Gobiye Resistant (Abate et al. 2017 ; Belay et al. 2021 ; Teka 2014 ) N13 Resistant (Mbuvi et al. 2017 ; Muchira et al. 2021 ) SRN-39 Resistant (Kawa et al. 2021 ; Temesgen 2019 ) Teshale Susceptible (Mulatu 2020 ; Temesgen 2019 ) Shanqo Red (SQR) Susceptible (Gobena et al. 2017 ; Kawa et al. 2021 ) Striga hermonthica seed collection The Striga hermonthica seeds used in this study were collected from severely infested sorghum fields across five distinct geographical locations in Ethiopia during the 2022 cropping season. Table 2 describes the geographical locations of the Striga collection sites. Healthy, intact Striga plants with no visible flowers or only the topmost flowers remaining were carefully collected from extensively infested areas using the methods described by Berner et al. ( 1997 ). The harvested Striga plants were spread out to dry on a large polyethylene sheet in a well ventilated, covered space. After 20 days of drying, during which shattered Striga seeds fell onto the sheet, the dried plants were carefully transferred to another polyethylene sheet, with the heads gently tapped to encourage seed shedding. The threshed Striga seeds from both sheets were then collected into separate containers and sieved through 250 and 150 micron open sieves. Finally, pure Striga seeds were placed in labeled plastic containers and stored in a refrigerator at the Holeta Agricultural Biotechnology Research Center. Table 2 The description of the geographical locations of the Striga collection site Location Zone Altitude (m.a.s.l) Location Assosa Assosa 1300–1570 10 o 04′′ N, 34 o 31′′ E Babile East Harerge 1646.88 09 o 13′ 19′′ N, 42 o 19′ 47′′ E Fedis East Harerge 1055.1 08 o 49′ 43′′ N, 42 o 00′ 45′′ E Kobe North Wolo 1476.49 12° 7′ 11.52′′ N, 39° 37′ 26.36′′ E Shewa Robit North Shoa 1235 09 o 59′ 53″ N, 39 o 53′ 53″ E Surface sterilization, preconditioning, and infestation of Striga seeds The procedure described by Taylor et al. ( 2024 ) was used for Striga seed surface sterilization and conditioning. A measured amount of viable Striga seeds from each ecotype was soaked in a separate flask containing 20% commercial bleach for ten minutes, followed by three rinses with autoclaved distilled water. The sterilized Striga seeds were then incubated at 30°C in the dark for 14 days. Conical pots with a volume of 5 liters, a height and top diameter of 20 cm, and a bottom diameter of 8 cm were selected for the experiment. Three kilograms of a 1:3 sand to soil mixture were placed into each pot. Before planting, approximately 7,500 (0.077 g) preconditioned Striga seeds were added to each pot containing the 3 kg sand/soil mixture and thoroughly mixed. Sorghum planting and growth monitoring under greenhouse conditions Three or four healthy sorghum seeds were sown in a 2–3 cm hole made in the center of each pot. After twelve days, one healthy and vigorous seedling per pot was retained, and the others were carefully thinned out. For this study, the fertigation method described by Berner et al. ( 1997 ) for Striga screening under controlled conditions was employed. Each pot received 0.113 g of NPS fertilizer at the time of thinning, followed by 0.052 g of nitrogen in the form of urea seven days later. During the first five weeks, each pot was watered with approximately 30 ml daily. For the remainder of the experiment, each pot continued to receive the same volume of water at daily intervals. Data collection Three Striga resistance related traits were measured ten weeks after sowing sorghum seeds: attached and emerging Striga count (SC), Striga length (SL), and dry biomass (SBM) (Joel et al. 2018; Kaubi 2016 ; Kavuluko et al. 2021 ; Mbuvi et al. 2017 ). Striga seedling attachments collected from each pot were counted and photographed on 90 mm Petri dishes. Dry Striga biomass was determined after the seedlings were oven dried for 24 hours at 60°C. Finally, the length of the attached Striga seedlings was measured using ImageJ v.1.45 software ( https://imagej.net/ij/download.html ), and the average length per pot was calculated (Joel et al. 2018). Statistical analysis A combined three way analysis of variance (ANOVA) for three Striga related quantitative traits was conducted using data from a randomized complete block design with factorial arrangements, comprising four replications, and carried out over two distinct seasons under controlled conditions. This analysis was performed using the R function fat3.rbd() from the ExpDes package (Ferreira et al. 2014 ). The significance of the mean squares for the main and interaction effects was assessed using least significant difference (LSD) tests at a P ≤ 0.05 probability level. The virulence levels of the five Ethiopian Striga ecotypes on resistant sorghum varieties alone, and including the two checks, were graphically summarized using SRplot, A free online platform for data visualization and graphing (Tang et al. 2023 ). Results Using five Ethiopian Striga ecotypes, this study evaluated the genetic variability of seven improved Striga resistant sorghum varieties, focusing on three Striga related traits. The response of different sorghum varieties to Striga infestation was assessed by measuring the total count, mean length, and dry biomass of Striga attached to the root zone of each sorghum variety (Kaubi 2016 ; Mbuvi et al. 2017 ). Significant genotypic variation was observed among the Striga resistant varieties across all three traits. Accordingly, there was significant genotypic variation between Striga resistant varieties in all three traits. SC (p < 0.001), SL (p < 0.05), and SBM (p < 0.01) were the three Striga related parameters to which the resistance of varieties varied significantly on the five Ethiopian Striga ecotypes (Table 3 ). Furthermore, when including the two standard checks, "SQR" and “Teshale,” in the analysis alongside the seven improved Striga resistant sorghum varieties, the significant genotypic variations in all three traits remained consistent (Supplementary Table S1 ). Conversely, in both analyses, the tested Striga ecotypes did not exhibit a significant effect on any of the measured traits (Table 3 and Supplementary Tables S1). Emphasizing the consequences of interactions, the two way interaction effects of variety by ecotype had a significant influence on SC and SBM in both analyses, including and excluding the standard checks traits (Table 3 and Supplementary Tables S1). However, a notable variety by ecotype interaction effect on SL was observed when evaluating the seven improved Striga resistant sorghum varieties without the two susceptible checks. This strong variety by ecotype interaction suggests that the responses of resistant varieties to the three parameters were significantly affected by the varying Striga ecotypes. A strong and significant three way interaction effect was detected for SBM in both analyses, with and without the standard checks (p < 0.001). Therefore, the impact of these interactions on SBM should be examined across different environmental levels. Consequently, using the seven improved Striga resistant sorghum varieties, this study primarily focused on the two way interaction effects of Striga ecotypes and varieties on SC and SL. Table 3 Combined three way ANOVA for seven improved resistant varieties across five Striga ecotypes and two seasons on SC, SL, and SBM, analysis of ecotypes inside each level of varieties for SC and SL, and analysis of varieties within each level of ecotype for SC and SL. Source of Variations DF Mean Squares SC SL SBM Variety 6 131.57*** 13.45*** 0.68* Ecotype 4 28.71 2.43 0.32 Environment 1 65.09* 11.34 2.32** Variety x Ecotype 24 54.69*** 5.48* 0.61** Variety x Environment 6 35.02* 3.10 0.34 Ecotype x Environment 4 2.05 3.31 0.22 Variety x Ecotype x Environment 24 7.6 4.97 0.73*** Ecotype x variety Abshir 4 58.84** 10.17* Ecotype x variety Berhan 4 29.96 0.97 Ecotype x variety BTx623 4 32.65 10.15* Ecotype x variety Framida 4 40.35* 10.09* Ecotype x variety Gobiye 4 99.9*** 0.84 Ecotype x variety N-13 4 1.23 0.36 Ecotype x variety SRN39 4 93.94*** 2.74 Variety x Ecotype Assosa 6 42.37* 9.11* Variety x Ecotype Babile 6 52.91** 1.04 Variety x Ecotype Fedis 6 34.37* 7.94* Variety x Ecotype Kobo 6 118.41*** 14.05*** Variety x Ecotype S/Robit 6 102.28*** 3.21 ***, **, * indicate significant at 0.1%, 1%, and 5% probability level respectively, SC: Striga count, SL: Striga Length, and SBM: Striga Biomass The analysis of ecotypes within each variety level is presented in Table 3 , which shows that the interaction effects of ecotypes within each variety level were significant. Specifically, the interaction effects of ecotypes with the varieties Abshir (p < 0.001), Framida (p < 0.05), Gobiye (p < 0.001), and SRN-39 (p < 0.001) on SC were significant. Similarly, the average SL of Abshir, BTx623, and Framida was influenced by their interactions with different Striga ecotypes. Variety Abshir exhibited higher SC with ecotypes from Assosa (6.13) and Kobo (9.75), whereas the number of attached Striga on variety Gobiye was lower for ecotypes from Assosa (2.50) and Kobo (2.63). Additionally, variety SRN-39 showed a high mean SC on the ecotype from Babile (9.38), while variety Framida exhibited significantly high and low mean SC on ecotypes from Assosa (3.75) and Fedis (4.75), respectively (Fig. 1 and Supplementary Table S2). The mean SL of variety Abshir was significantly lower on ecotypes from Babile (0.87 cm) and Fedis (1.22 cm). In contrast, sorghum variety BTx623 had significantly higher mean SL on ecotypes from Fedis (3.6 cm), and variety Framida showed higher mean SL on ecotypes from Assosa (2.17 cm) and Kobo (3.76 cm) (Fig. 2 and Supplementary Table S3). Consequently, the mean SC and SL responses of ecotypes within each variety confirmed the immune response of certain varieties to the tested Striga ecotypes, such as Abshir for ecotypes from Babile, Fedis, and S/Robit; BTx623 for ecotypes from Kobo and S/Robit; and Gobiye for ecotypes from Assosa and Kobo. Furthermore, the strong immune response of N13 was confirmed across all tested Striga populations. Overall, all examined resistant varieties, except Berhan and N13, had a significant effect on the mean performance of ecotypes for SC and SL (Table 3 ). The virulence levels of five Ethiopian Striga ecotypes were investigated by analyzing their interaction effects with seven improved Striga resistant sorghum varieties for SC and SL. The analysis of the seven improved resistant varieties within each ecotype level for SC and SL (Table 3 ) showed that, under the Striga ecotypes Assosa (p < 0.05), Babile (p < 0.01), Fedis (p < 0.05), Kobo (p < 0.001), and S/Robit (p < 0.001), the number of Striga attached to the root zone of the varieties varied significantly. Similarly, for the sorghum varieties, performance differences in the length of attached Striga were significant under the Striga ecotypes Assosa (p < 0.05), Fedis (p < 0.05), and Kobo (p < 0.001) (Table 3 ). The analysis of the varieties' mean SC and SL within each ecotype (Fig. 3 and Fig. 4 ) revealed that the Assosa Striga ecotype exhibited a significantly higher number of Striga attachments on the varieties Abshir (6.13) and BTx623 (6.88), as well as the greatest SL on Abshir (3.65 cm) and Framida (2.17 cm). Similar to the varieties Berhan and Framida, the Striga ecotype from Babile showed substantially higher attachments to variety SRN-39 (9.38). Striga ecotype Fedis on variety BTx623 (3.50 and 3.60 cm) and Gobiye (7.38 and 1.98 cm), and Kobo on variety Abshir (9.75 and 2.69 cm) and Framida (9.63 and 3.76 cm) were found to have significantly more attachments and longer mean lengths. The Striga ecotype from S/Robit severely affected variety Gobiye (10.88). The analysis of the nine varieties (seven resistant and two susceptible varieties) means SC and SL within each ecotype further supports the variation in virulence levels of major Ethiopian Striga ecotypes on the developed sorghum varieties (Supplementary Tables S4 and S5) Discussion Continuous screening of sorghum genotypes and identifying the most resistant varieties under uniform Striga infestation conditions is crucial to mitigating the increasingly severe impact of Striga on sorghum production. The mean number, mean length, and dry biomass of Striga growing on the roots of each of the sorghum varieties were used to classify their reaction to the parasite. Resistant varieties exhibited the fewest attachments, the shortest Striga length, and the lowest dry biomass on their roots (Joel et al. 2018; Kavuluko et al. 2021 ). All resistant sorghum varieties studied exhibited some level of successful parasite attachment to the roots, as complete resistance to Striga has not been identified in cultivated sorghum varieties (Gurney et al. 2002 ). Our pot experiment revealed that released Striga resistant sorghum varieties respond differently to Striga infection on the three resistance traits. This variation suggests that some varieties may possess more effective resistance mechanisms against the parasite, while others may lack such defenses. Similar differences in resistance responses among sorghum varieties under Striga infested conditions have been reported by Abate et al. ( 2017 ), Ayana (2019), Fisseha et al. ( 2023 ), Mamo et al. ( 2020 ), and Mbuvi et al. ( 2017 ). The primary focus of this study was the observed two way interaction effects between Striga ecotypes and sorghum varieties on SC and SL, which determine the virulence levels of Striga ecotypes on different sorghum varieties and the resistance responses of various sorghum varieties to different Striga ecotypes. The presence of an interaction effect suggests that different sorghum varieties vary in their capacity to stimulate germination or withstand infections from different Striga ecotypes, and vice versa (Musimwa 2005 ; Haussmann et al. 2001 ). This indicates that some sorghum genotypes exhibit ecotype specific resistance, while others demonstrate strong and broad resistance across multiple ecotypes. According to Huang et al. ( 2012 ), the interaction between Striga populations and varieties significantly influences the success of parasites attaching to hosts. Therefore, this interaction effect has important implications for identifying resistant genotypes for breeding purposes, suggesting that breeding Striga resistant sorghum may be more complex than it initially appears. Similar studies have also demonstrated the interaction effects between the host and Striga populations, which determine host resistance and parasite virulence (Bozkurt et al. 2015 ; Haussmann et al. 2001 ; Huang et al. 2012 ; Rodenburg et al. 2017 ). Strong interactions reflect the presence of distinct resistance responses to specific Striga populations and the complexity of Striga virulence toward particular sorghum (Bozkurt et al. 2015 ). An ecotype study within each variety revealed that both the length of Striga attachments on Abshir, BTx623, and Framida varieties, and the number of Striga attachments on Abshir, Framida, Gobiye, and SRN-39 varieties, were significantly influenced by changes in Striga ecotype. The responses of these varieties to different Striga ecotypes affect both the total number and length of Striga attachments near their root zones. Beyond differences in low Striga germination stimulation (Yohannes et al. 2016 ), the varied responses of genotypes to infection by different Striga populations may also result from differences in resistance mechanisms among resistant genotypes (Muchira et al. 2021 ). Comparatively, the mean performance of the Abshir variety confirmed its stronger resistance to Striga ecotypes Babile and Fedis. Framida exhibited superior resistance to Striga ecotypes Assosa and Fedis. Gobiye’s resistance was more pronounced against ecotypes Assosa and Kobo than others. SRN-39 and BTx623 showed stronger resistance reactions across all Striga populations except Babile and Fedis, respectively. This inconsistency suggests that when varieties are exposed to different Striga populations, their genetic potential for resistance may include traits that either enhance strong resistance or confer partial resistance to Striga . Similarly, Haussmann et al. ( 2001 ) demonstrated an entry-by-country interaction effect, indicating that entries identified as Striga resistant in Kenya may not be resistant in Mali. Overall, the interaction effect highlights significant variation in Striga resistance, revealing that sorghum varieties from distinct geographic regions respond differently to Striga infestation. Sorghum variety development and recommendations targeted at specific Striga ecotypes may not always be effective due to the high genetic variability among Striga populations in Ethiopia (Welsh and Mohamed 2011 ). This genetic diversity enables the parasite to evolve and adapt to changing environmental conditions (Unachukwu et al. 2017 ), often overcoming the resistance of varieties, especially when new Striga races infest the area (Rispail et al. 2007 ). The total number of Striga attachments in the root zones of sorghum varieties varied significantly when infected with Striga ecotypes from Assosa, Babile, Fedis, Kobo, and S/Robit. Similarly, infection by Striga ecotypes from Assosa, Fedis, and Kobo had a significant impact on the length of the attached Striga across different sorghum varieties. According to Bozkurt et al. ( 2015 ), the strong interaction effect indicates distinct variations in Striga virulence toward specific sorghum varieties. The variety analysis at each ecotype level further confirms the presence of variable virulence levels of Striga ecotypes on the tested sorghum varieties (Fig. 5 ). Rodenburg et al. ( 2017 ) also reported variation in Striga virulence across species and ecotypes. Striga populations in Ethiopia exhibit a high degree of genetic diversity, with geographic distribution playing a crucial role in shaping this diversity (Welsh and Mohamed 2011 ). The extensive genetic diversity of Striga is driven by the parasite’s boundless variability, exceptionally high seed production and fecundity, and the geographic distance of ecotypes (Ejeta et al. 2007 ; Welsh and Mohamed 2011 ), all of which determine their virulence and the effectiveness of host resistance (Haussmann et al. 2001 ). Consequently, the distinct geographic origins of the five Striga populations likely contribute to the observed variability in Striga virulence against released Striga resistant sorghum varieties. The mean number and length of attached Striga plants surrounding the root zone of improved Striga resistant sorghum varieties within each Striga ecotype were used to determine the virulence levels of the five Striga ecotypes. For the seven improved Striga resistant sorghum varieties, the virulence level of each evaluated Ethiopian Striga ecotype varied significantly. This study showed that the Assosa ecotype exhibited greater virulence toward the varieties BTx623, Framida, and Abshir, while demonstrating reduced virulence against N13 and SRN-39. The Babile ecotype was less virulent to N13 and Abshir but more virulent to SRN-39, Framida, and Berhan. The Fedis ecotype was significantly less virulent to N13 and SRN-39 compared to its effects on Gobiye, Berhan, Framida, and BTx623. The Kobo ecotype was less virulent to Berhan, BTx623, Gobiye, N13, and SRN-39, but more virulent to Abshir and Framida. The final tested Striga ecotype, S/Robit, showed significantly higher virulence toward Gobiye and lower virulence toward N13, BTx623, and SRN-39. According to Haussmann et al. ( 2001 ), the interaction of Striga ecotype and host variety influences Striga resistance; they also observed that Striga ecotypes highly virulent to one variety may not be virulent to another. Even if Striga ecotypes had varying effects on different varieties, this study found that every ecotype exhibited a lower virulence towards variety N13 and SRN-39 while having higher virulence towards variety Framida. The development of resistant sorghum varieties has proven to be quite challenging for plant breeders due to the varying resistance responses of sorghum genotypes across different ecotypes and the differing infection levels of Striga populations on these genotypes. Consequently, cultivated sorghum varieties are not completely resistant to Striga (Gurney et al. 2002 ). In this study, varieties N13 and SRN-39 consistently exhibited higher resistance across all Striga ecotypes. Other studies also demonstrate that N13 (Joel et al. 2018; Mohamed et al. 2010 ) and SRN-39 (Ezeaku and Gupta 2004 ; Mohamed et al. 2010 ; Muchira et al. 2021 ) effectively defend against various Striga infections. The resistance mechanisms in N13 and SRN-39 are reported to involve low germination stimulation and a mechanical barrier to Striga penetration, attributed to their high lignin and suberin deposition, respectively. Understanding these resistance mechanisms facilitates gene pyramiding (Muchira et al. 2021 ). The consistent resistance and distinct mechanisms of these two sorghum varieties may aid Striga resistance breeding programs and enhance Striga management efforts. Furthermore, knowledge of how Striga ecotypes differ in virulence simplifies the identification of resistance genes capable of producing genotypes resistant to multiple ecotypes (Unachukwu et al. 2017 ). Overall, this study provides crucial information for mapping the N13 and SRN-39 genes in adapted high yielding genotypes and screening them under diverse Striga infected conditions. Evaluating breeding materials across multiple environments against different host specific Striga populations is essential for selecting stable resistance (Haussmann et al. 2001 ). Conclusions The genetic variation of sorghum varieties, the interaction effect of varieties with Striga ecotypes, and the virulence differences of five major Ethiopian Striga ecotypes for the resistance varieties were assessed in this activity. The significant interaction effect of major Ethiopian Striga ecotypes with resistant sorghum varieties articulates the complexity of Striga ’s virulence. The result of this study revealed that certain Striga ecotypes showed higher virulence levels to some of the sorghum varieties but lesser to the others; similarly, certain sorghum varieties showed more resistance or susceptibility to each of the ecotypes. Such strong virulence level variation highlights the importance of ecotypes in determining varietal selection for Striga resistance and developing targeted breeding strategies that enhance resistance to Striga infestations. The clear differences in resistance reaction are shown by the contrasting behaviors of Framida and N13 across all ecotypes. Varieties N13 and SRN-39 showed a consistently higher resistance reaction across multiple ecotypes, which may facilitate the strategic pyramiding of different resistance genes within identified high-yielding genotypes, and researchers can enhance breeding programs aimed at developing Striga -resistant sorghum varieties. One of the main factors influencing population structure (virulence) in Ethiopia is the wide geographic range of sorghum-growing locations. Therefore, exhaustive studies on the genetic variability of Ethiopian Striga ecotypes facilitate the development of durable resistant genotypes. Furthermore, combining controlled testing and multi-ecotype evaluation of genotypes with multiple resistance mechanisms may serve as an effective sorghum breeding strategy for Striga -affected farmers in Ethiopia. Abbreviations AATF: Africa Agricultural Technology Foundation ISM: Integrated Striga management SBM: Striga Biomass SC: Striga Count SL: Striga Length SSA: Sub Saharan Africa Declarations Funding This work was funded by the Amhara Agricultural Research Institute (ARARI) and the National Sorghum Improvement Program, Melkasa Agricultural Research Center, Ethiopia Institute of Agricultural Research. Competing interests The authors declare no relevant financial or non-financial interests to release. Ethical approval Ethical approval has been given for the software, as well as previous studies we used to refer to and discuss in this publication, and the manuscript acknowledges all the works. Informed consent : Not applicable Data availability The dataset generated during the experiment is available from the corresponding author on reasonable request. The analyzed data supporting the texts and figures of this manuscript are included in supplementary information files. Authors’ contribution Conceptualization and design of the experiment were performed by Abiy Legesse, Habte Nida, and Alemu Tirfesa. Material preparation, execution of pot experiments, and data collection were executed by Abiy Legesse, Hewan Demissie, and Taye Tesema. Data interpretation of results and preparation of the manuscript were done by Abiy Legesse. The first draft of the manuscript was written by Abiy Legesse, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Corresponding author: Correspondence to Abiy Legesse Kibebe References AATF (Africa Agricultural Technology Foundation) (2011) Feasibility Study on Striga Control in Sorghum. Africa Agricultural Technology Foundation, Nairobi Abate M, Hussien T, Bayu W, Reda F (2017) Screening of Ethiopian sorghum ( Sorghum bicolor (L.) Moench) landraces for their performance in Striga hermonthica (Del.) Benth infested conditions. Plant Breeding. https://doi.org/10.1111/pbr.1251 Ahmed A, Elsafy M, Zhourghane A, Abdalla AA, Abreha KB, Geleta M, Rahmatov M, Abdelhalim TS (2024) Exploring the genetic variability of Sudanese wild sorghum ( Sorghum bicolor (L.) Moench) germplasm for post-attachment Striga hermonthica resistance mechanisms using single sequence repeat (SSR) primers. Genetic Resources and Crop Evolution 72:4583–4595. https://doi.org/10.1007/s10722-024-02230-w Ayana TT, Bantte K, Tadesse T (2019) Evaluation of Ethiopian Sorghum [ Sorghum bicolor (L.) Moench] Landraces: Low germination stimulant genotypes for Striga hermonthica resistance under field conditions. Advanced Crop Science Technology 7:444. http://dx.doi.org/10.4172/2329-8863.1000444 Belay F, Firew M, Taye T (2021) Univariate stability analysis and relationship among parameters for grain yield of Striga -resistant sorghum hybrids in Ethiopia. Open Journal of Plant Science 6:069-081. DOI: https://dx.doi.org/10.17352/ojps.000036 Berner DK, Winslow MD, Awad AE, Cardwell KF, Mohan Raj DR, Kim SK (1997) Striga Research Methods Manual, 2 nd edn. International Institute of Tropical Agriculture PMB 5320, Ibadan, Nigeria Bozkurt ML, Muth P, Parzies HK, Haussmann BIG (2015) Genetic diversity of East and West African Striga hermonthica populations and virulence effects on a contrasting set of sorghum cultivars. Weed Research 55:71-81. https://doi.org/10.1111/wre.12117 Dossa EN, Shimelis H, Shayanowako AIT, Laing MD (2023) A meta-analysis of the effects of Striga control methods on maize, sorghum, and major millet production in sub-Saharan Africa. Crop Science 63:460-479. https://doi.org/10.1002/csc2.20889 Earecho MK, Nebiyu E, Alemu H (2024) Evaluation of Western Ethiopian sorghum landraces for resistance to Striga hermonthica (Del.) Benth. Advanced Crop Science Technology 12:690 Ejeta G (2007a) Breeding for Striga resistance in sorghum: Exploitation of an intricate host-parasite biology. Crop Science 47:216-227. https://doi.org/10.2135/cropsci2007.04.0011IPBS Ejeta G (2007b) The Striga Scourge in Africa: A Growing Pandemic. In: Ejeta G, Gressel J. Integrating new technologies for Striga control towards ending the witch-hunt. World Scientific Publishing Co Pte Ltd, Singapore, PP 3–16 Ejeta G, Patrick J, Mohamed RA (2007) Dissecting a complex trait into simpler components for effective breeding of sorghum with a high level of Striga resistance. In: Ejeta G, Gressel J. Integrating new technologies for Striga control towards ending the witch-hunt. World Scientific Publishing Co Pte Ltd, Singapore, PP 87–98 Emechebe AM, Ellis-Jones J, Schulz S, Chikove D, Douthwaite B, Kureh I, Tarawali G, Hussaini MA, Kormawa P, Sanni A (2004) Farmers’ perception of the Striga problem and its control in northern Nigeria. Expl Agric 40:215–232 Ezeaku IE, Gupta SC (2004) Development of sorghum populations for resistance to Striga hermonthica in the Nigerian Sudan Savanna. African Journal of Biotechnology 3:324–29. https://doi.org/10.5897/AJB2004.000-2059 Ferreira EB, Cavalcanti PP, Nogueira DA (2014) ExpDes: An R package for Analysis of Variance (ANOVA) and experimental designs. Applied Mathematics 5:2952–2958. http://dx.doi.org/10.4236/am.2014.519280 Fisseha W, Teshome K, Tarekegn F (2023) Yield performance and stability evaluation of Striga -resistant sorghum ( Sorghum bicolor [L.] Moench). Journal of Plant Breeding and Crop Science 15:90–98. https://doi.org/10.5897/JPBCS2022.0998 Gethi JG, Smith ME, MitchelLà SE, Kresovichà S (2005) Genetic diversity of Striga hermonthica and Striga asiatica populations in Kenya. Weed Research 45:64–73. http://dx.doi.org/10.1111/j.1365-3180.2004.00432.x Gobena D, Mahdere S, Patrick JR, Carolien R, Harro B, Satish K, Tesfaye M, Gebisa E (2017) A mutation in the sorghum low germination stimulant alters strigolactones and causes Stria resistance. Proc Natl Acad Sci 114:4471–4476. https://doi.org/10.1073/pnas.1618965114 Gurney AL, Press MC, Scholes JD (2002) Can wild relatives of sorghum provide new sources of resistance or tolerance against Striga species? Weed Research 42:317–324. http://dx.doi.org/10.1046/j.1365-3180.2002.00291.x Haussmann B, Hess D, Reddy B, Mukuru S, Kayentao M, Welz H, Geiger H (2001) Pattern analysis of genotype × environment interaction for Striga resistance and grain yield in African sorghum trials. Euphytica 122:297–308. https://doi.org/10.1023/A:1012909719137 Huang K, Whitlock R, Press MC, Scholes JD (2012) Variation for host range within and among populations of the parasitic plant Striga hermonthica . Heredity 108:96–104. https://doi.org/10.1038/hdy.2011.52 Joel Kataka Atanda, Runo S, Muchugi A (2018) Genetic diversity and virulence of Striga hermonthica from Kenya and Uganda on selected sorghum varieties. Nusantara Bioscience 10:111–120. http://dx.doi.org/10.13057/nusbiosci/n100208 Kaubi NH (2016) Evaluation of maize ( Zea Mays L.) genotypes with multiple resistance to Striga hermonthica (Del.) Benth and Striga asiatica (L.) Kuntze. Dissertation, University of Zambia Kavuluko J, Kibe M, Sugut I, Kibet W, Masanga J, Mutinda S, Wamalwa M, Magomere T, Odeny D, Runo S (2021) GWAS provides biological insights into the mechanisms of the parasitic plant ( Striga ) resistance in sorghum. BMC Plant Biology 21:1-15 https://doi.org/10.1186/s12870-021-03155-7 Kawa D, Taylor T, Thiombiano B, Musa Z, Vahldick HE, Walmsley A, Bucksch A, Bouwmeester H, Brady SM (2021) Characterization of growth and development of sorghum genotypes with differential susceptibility to Striga hermonthica . Journal of Experimental Botany 72:7970–7983. https://doi.org/10.1093/jxb/erab380 Mamo M, Worede F, Bantayehu M (2020) Evaluation of sorghum ( Sorghum bicolor (L.) Moench) genotypes for Striga resistance and yield and yield-related traits. Black Sea Journal of Agriculture 3:85-95 Mbuvi DA, Masiga CW, Kuria E, Masanga J, Wamalwa M, Mohamed A, Odeny D, Hamza N, Timko MP, Runo S (2017) Novel sources of witchweed ( Striga ) resistance from wild sorghum accessions. Frontiers in Plant Science 8:116. https://doi.org/10.3389/fpls.2017.00116 Mohamed AH, Housley TL, Ejeta, G (2010) An in vitro technique for studying specific Striga resistance mechanisms in sorghum. African Journal of Agricultural Research 5:1868-1875 Mrema E, Shimelis H, Lying M, Mwadzingeni L (2020) Integrated management of Striga hermonthica and S. asiatica in sorghum. Australian Journal of Crop Science 14:36–45. http://dx.doi.org/10.21475/ajcs.20.14.01.p1749 Muchira N, Ngugi K, Wamalwa LN, Avosa M, Chepkorir W, Manyasa E, Nyamongo D, Odeny DA (2021) Genotypic variation in cultivated and wild sorghum genotypes in response to Striga hermonthica infestation. Frontiers in Plant Science 12:671984. https://doi.org/10.3389/fpls.2021.671984 Mulatu G (2020) Screening for the Striga ( Striga Hermonthica (Del.) Benth.) resistance gene in sorghum ( Sorghum Bicolor (L.) Moench) genotypes using Gel-Based Assay and the Lgs1 Marker in Ethiopia. Dissertation, Addis Ababa University Musimwa C (2005) Genetic variability, host specificity, and resistance in Striga asiatica -host plant interactions. Dissertation, University of Zimbabwe Parker C (2012) Parasitic Weeds: A World Challenge. Weed Science 60:269–276. https://doi.org/10.1614/WS-D-11-00068.1 Qiu S, Bradley JM, Zhang P, Chaudhuri R, Blaxter M, Butlin RK, Scholes JD (2022) Genome-enabled discovery of candidate virulence loci in Striga hermonthica , a devastating parasite of African cereal crops. New Phytologist 236:622-638. https://doi.org/10.1111/nph.18305 Rispail N, Dita MA, González-Verdejo C, Pérez-De-Luque A, Castillejo MA, Prats E, Román B, Jorrín J, Rubiales D (2007) Plant resistance to parasitic plants: Molecular approaches to an Old foe. New Phytologist 173:703–712. https://doi.org/10.1111/j.1469-8137.2007.01980.x Rodenburg J, Bastiaans L, Weltzien E, Hess DE (2005) How can field selection for Striga resistance and tolerance in sorghum be improved? Field Crops Research 93:34–50. https://doi.org/10.1016/j.fcr.2004.09.004 Rodenburg J, Cissoko M, Kayongo N, Dieng I, Bisikwa J, Irakiza R, Masoka I, Midega CA, Scholes JD (2017) Genetic variation and host-parasite specificity of Striga resistance and tolerance in rice: the need for predictive breeding. New Phytol 214:1267-1280 Scholes JD, Press MC (2008) Striga infestation of cereal crops-an unsolved problem in resource-limited agriculture. Current Opinion in Plant Biology 11:180–186. http://dx.doi.org/10.1016/j.pbi.2008.02.004 Tang D, Chen M, Huang X, Zhang G, Zeng L, Zhang G, Zeng L, Zhang G, Wu S, Wang Y (2023) SRplot: A free online platform for data visualization and graphing. PLOS ONE 18:e0294236. https://doi.org/10.1371/journal.pone.0294236 Taylor T, Daksa J, Shimels MZ, Etalo DW, Thiombiano B, Walmsey A, Chen AJ, Bouwmeester HJ, Raaijmakers JM, Brady SM, Kawa D (2024) Evaluating mechanisms of soil microbiome suppression of Striga infection in sorghum. Bio-Protocol 14:e5058. https://doi.org/10.21769/BioProtoc.5058. Teka HB (2014) Advanced research on Striga control: A review. African Journal of Plant Science 8:492-506. https://doi.org/10.5897/AJPS2014.1186 Temesgen T (2019) Review on Striga distribution, infestation, and genetic potential in Ethiopian sorghum ( Sorghum bicolor (L.) Moench). International Journal of Research Studies in Agricultural Sciences 5:23–31. http://dx.doi.org/10.20431/2454-6224.0502004 Tesso T, Gebisa E (2011) Integrating multiple control options enhances Striga management and sorghum yield on heavily infested soils. Agronomy Journal 103:1464–1471. https://doi.org/10.2134/agronj2011.0059 Unachukwu NN, Menkir A, Rabbi IY, Oluoch M, Muranaka S, Elzein A, Odhiambo G, Farombi EO, Gedil M (2017) Genetic diversity and population structure of Striga hermonthica populations from Kenya and Nigeria. Weed Research 57:293-302. https://doi.org/10.1111/wre.12260 Welsh AB, Mohamed KI (2011) Genetic diversity of Striga hermonthica populations in Ethiopia: Evaluating the role of geography and host specificity in shaping population structure. International Journal of Plant Sciences 172:773–782. https://doi.org/10.1086/660104 Yohannes T, Ngugi K, Ariga E, Abraha T, Yao N, Asami P, Ahonsi M (2016) Genotypic variation for low Striga germination stimulation in sorghum ( Sorghum bicolor (L.) Moench) landraces from Eritrea. American Journal of Plant Sciences 7:2470-2482. https://doi.org/10.4236/ajps.2016.717215 Yonli D, Traore H, Van Mourik TA, Hess DE, Sereme P, Sankara P (2012) Integrated control of Striga hermonthica (Del.) Benth. in Burkina Faso through host plant resistance, biocontrol, and fertilizers. International Journal of Biological and Chemical Sciences 5:1860. https://doi.org/10.4314/ijbcs.v5i5.8 Additional Declarations No competing interests reported. Supplementary Files SupplementaryTable.docx Supplementary Tables Additional information is attached to the “Supplementary Table” file. In the file, there are tables from S1 to S8 as follows: S1. Combined three-way ANOVA for seven improved resistant varieties and two checks across five Striga ecotypes and two seasons on SC, SL, and SBM S2. Ecotypes mean SC inside each level of a variety (seven improved resistant varieties) S3. Ecotype mean SL (cm) inside each level of a variety (seven improved resistant varieties) S4. Seven resistant sorghum varietiesmean SC inside the level of ecotypes. S5. Seven resistant sorghum varietiesmean SL (cm) inside the level of ecotypes. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7448410","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":507091955,"identity":"69a78fc0-744d-46a1-a736-0d97721456dc","order_by":0,"name":"Abiy Legesse Kibebe","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYDACCcYGBoaKGjkQ+8AD4rWcOWYM1pJAnBYgZmxjTmwAcYjSwj+7uU2a5wxb+vywww+BttjJ6TYQsuTOQaCWCpncjbfTDIBako3NDhCy5kYi2JbcjbMTQFoOJG4jpEUepIW3jTndcHb6B+K0GEC1JMhL5xBpi+Gdg82Wc84cM9wgnVNwIMGACL/I3W5/eONNRY28/Oz0zR8+VNjJEfY+AwOLBNiFYJUGhJWDAPMHECnfQJzqUTAKRsEoGIEAAFetSLhRpjB7AAAAAElFTkSuQmCC","orcid":"","institution":"Amhara Regional Agricultural Research Institute","correspondingAuthor":true,"prefix":"","firstName":"Abiy","middleName":"Legesse","lastName":"Kibebe","suffix":""},{"id":507091956,"identity":"34a949e4-1037-4f3f-b5b2-a81e1c9a11a6","order_by":1,"name":"Hewan Demissie Degu","email":"","orcid":"","institution":"Hawassa University","correspondingAuthor":false,"prefix":"","firstName":"Hewan","middleName":"Demissie","lastName":"Degu","suffix":""},{"id":507091958,"identity":"c202dc9a-7437-4381-be72-ccda95530f42","order_by":2,"name":"Taye Tesema","email":"","orcid":"","institution":"National Integrated Striga Control Project Coordinator","correspondingAuthor":false,"prefix":"","firstName":"Taye","middleName":"","lastName":"Tesema","suffix":""},{"id":507091963,"identity":"4a608de6-6500-40bb-adaf-922b715504aa","order_by":3,"name":"Habte Neda Chikssa","email":"","orcid":"","institution":"Purdue University","correspondingAuthor":false,"prefix":"","firstName":"Habte","middleName":"Neda","lastName":"Chikssa","suffix":""},{"id":507091964,"identity":"22e1b9d9-4e72-4b4a-ad10-a826d464139b","order_by":4,"name":"Alemu Tirfessa Woldentensaye","email":"","orcid":"","institution":"Kansas State University (KSU)","correspondingAuthor":false,"prefix":"","firstName":"Alemu","middleName":"Tirfessa","lastName":"Woldentensaye","suffix":""}],"badges":[],"createdAt":"2025-08-24 22:23:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7448410/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7448410/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90430036,"identity":"38ad4d9c-2247-4df2-818a-76cb1a23d11c","added_by":"auto","created_at":"2025-09-02 15:29:02","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":176233,"visible":true,"origin":"","legend":"\u003cp\u003eEcotypes mean SC inside each level of a variety\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMeans with the same letter are not significantly different at 5% probability level, and ns: non-significant\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/4fe648a8fa80055e5497d726.png"},{"id":90431487,"identity":"fb3912b5-798e-4ef7-9d28-aae4704abed6","added_by":"auto","created_at":"2025-09-02 15:45:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":162093,"visible":true,"origin":"","legend":"\u003cp\u003eEcotypes mean SL inside each level of a variety\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMeans with the same letter are not significantly different at 5% probability level, and ns: non-significant\u003c/em\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/222d54ac7d7668d4e0cace4c.png"},{"id":90431812,"identity":"73535627-9152-4f56-86bd-979b213a9edc","added_by":"auto","created_at":"2025-09-02 15:53:02","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":106397,"visible":true,"origin":"","legend":"\u003cp\u003eVariety mean SC inside each level of the ecotypes\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMeans with the same letter are not significantly different at 5% probability level\u003c/em\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/ea9c7fe797ec4ffb82627127.png"},{"id":90430038,"identity":"83f393bb-09d1-4209-b0bf-fbfbd03efbc7","added_by":"auto","created_at":"2025-09-02 15:29:02","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":115939,"visible":true,"origin":"","legend":"\u003cp\u003eVariety mean SL inside each level of the ecotypes\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMeans with the same letter are not significantly different at 5% probability level, and ns: non-significant\u003c/em\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/368ac6398e0e67908807afa4.png"},{"id":90430049,"identity":"3539b1c6-54f4-451e-bfbf-d019d04c0ae7","added_by":"auto","created_at":"2025-09-02 15:29:02","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":328840,"visible":true,"origin":"","legend":"\u003cp\u003eSummary on variations in the virulence level of major Ethiopian \u003cem\u003eStriga\u003c/em\u003eecotypes. \u003cstrong\u003e(A)\u003c/strong\u003e SC of seven resistance sorghum varieties, \u003cstrong\u003e(B)\u003c/strong\u003e SL (cm) of seven resistance sorghum varieties, and \u003cstrong\u003e(C)\u003c/strong\u003eSC of seven resistance sorghum varieties and two susceptible checks.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/000eb98639788aaf114abf7d.png"},{"id":90432480,"identity":"c3d5e0fe-8db9-4377-8615-3b51af3fd811","added_by":"auto","created_at":"2025-09-02 16:01:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1711590,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/cce63876-6d62-426e-8de9-20fd43aa2fef.pdf"},{"id":90430403,"identity":"33b572a0-2bbd-4da2-93ac-e287130f11b4","added_by":"auto","created_at":"2025-09-02 15:37:02","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":21477,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSupplementary Tables\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAdditional information is attached to the “Supplementary Table” file. In the file, there are tables from S1 to S8 as follows:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eS1.\u003c/strong\u003e Combined three-way ANOVA for seven improved resistant varieties and two checks across five \u003cem\u003eStriga\u003c/em\u003e ecotypes and two seasons on SC, SL, and SBM\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eS2.\u003c/strong\u003e \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eEcotypes mean SC inside each level of a variety (seven improved resistant varieties)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eS3.\u003c/strong\u003e Ecotype mean SL (cm) inside each level of a variety (seven improved resistant varieties)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eS4.\u003c/strong\u003e Seven resistant sorghum varietiesmean SC inside the level of ecotypes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eS5.\u003c/strong\u003e Seven resistant sorghum varietiesmean SL (cm) inside the level of ecotypes.\u003c/p\u003e","description":"","filename":"SupplementaryTable.docx","url":"https://assets-eu.researchsquare.com/files/rs-7448410/v1/737e523735c8c167d80a046c.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Unveiling the Ecotype driven Virulence Heterogeneity among Major Ecotypes of the Striga hermonthica Population from Ethiopia","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSorghum (\u003cem\u003eSorghum bicolor\u003c/em\u003e) is one of the most important cereal crops for people in Sub Saharan Africa (SSA), serving as a source of food, feed, nutrients, and various other resources. In this region, its production is severely limited by the most significant biotic constraint: \u003cem\u003eStriga\u003c/em\u003e (AATF 2011; Gethi et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). \u003cem\u003eStriga\u003c/em\u003e species are obligate root parasites that infest staple crops across the Middle East and parts of Asia (Parker \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). A large proportion of \u003cem\u003eStriga\u003c/em\u003e species, over 80%, are found in Africa (Joel et al. 2018).\u003c/p\u003e\u003cp\u003e\u003cem\u003eStriga hermonthica\u003c/em\u003e is one of the most economically damaging \u003cem\u003eStriga\u003c/em\u003e species in several regions of the world, especially in SSA (AATF 2011). The geographical distribution and area coverage of \u003cem\u003eStriga\u003c/em\u003e are gradually expanding due to various factors, including declining soil fertility, shorter fallow periods, cultivation shifting to marginal lands, and continuous monoculture practices (Ejeta \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2007b\u003c/span\u003e; Emechebe et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). \u003cem\u003eStriga\u003c/em\u003e significantly limits sorghum production and may result in total crop loss (Ejeta \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007a\u003c/span\u003e; Muchira et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The loss has severe economic consequences for farmers, which adversely affect their livelihoods (Emechebe et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). \u003cem\u003eStriga\u003c/em\u003e infestation is a major economic concern in Ethiopian sorghum growing regions. This problem is particularly prevalent in Tigray, South and North Wollo, Gonder, Gojam, North Shewa, Gambela, Benishangul Gumuz, and Eastern Hararge (Temesgen \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Earecho et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Therefore, addressing \u003cem\u003eStriga\u003c/em\u003e infestations through comprehensive efforts is essential to ensure sustainable farming practices and economic stability.\u003c/p\u003e\u003cp\u003eIntegrated \u003cem\u003eStriga\u003c/em\u003e Management (ISM) is now an effective method for reducing the effects of \u003cem\u003eStriga\u003c/em\u003e on sorghum production. This method combines resistance genotypes with a variety of management strategies (Mrema et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Yonli et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Resistant varieties are now a central component of all ISM approaches in sorghum (Tesso and Ejeta 2011). The advantages of this approach include cost effectiveness, sustainability, environmental friendliness, and suitability for small scale farmers (Mrema et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Tesso and Ejeta 2011; Yonli et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). This confirms that breeding sorghum for \u003cem\u003eStriga\u003c/em\u003e resistance has long term effects on agricultural productivity, particularly in areas where \u003cem\u003eStriga\u003c/em\u003e infestation is a major issue (Dossa et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn Ethiopia, research on \u003cem\u003eStriga\u003c/em\u003e resistance or tolerance has achieved some success (AATF 2011). Since the beginning of the sorghum breeding program for \u003cem\u003eStriga\u003c/em\u003e resistance, several \u003cem\u003eStriga\u003c/em\u003e resistant varieties have been developed, recommended, and incorporated into breeding programs targeting \u003cem\u003eStriga\u003c/em\u003e infested regions of Ethiopia. These varieties includes \"Berhan,\" \"Gobiye,\" \"Abshir,\" \"Framida,\" \"N13,\" \"SRN-39,\" \"BTx623,\" and \"Tetron.\" (Abate et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Ahmed et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Belay et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Teka \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Gobena et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Kawa et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mbuvi et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Muchira et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Rodenburg et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Temesgen \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). However, different infested regions have different levels of success with resistant varieties in reducing the effects of \u003cem\u003eStriga\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eDue to the high genetic diversity of \u003cem\u003eStriga\u003c/em\u003e species, the weak level of host resistance that tends to break down with the infestation of new \u003cem\u003eStriga\u003c/em\u003e races (Rispail et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), and the rapid evolution of parasite virulence (Qiu et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), the \u003cem\u003eStriga\u003c/em\u003e breeding program and the use of resistant varieties have been complex and ineffective. \u003cem\u003eStriga\u003c/em\u003e populations in Ethiopia exhibit a high degree of genetic diversity, with geographical distribution playing a significant role in shaping this diversity (Welsh and Mohamed \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The extensive genetic diversity of \u003cem\u003eStriga\u003c/em\u003e determines its virulence level and the success of host resistance (Haussmann et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe development of long lasting sorghum varieties resistant to various \u003cem\u003eStriga\u003c/em\u003e populations across different ecotypes requires a comprehensive understanding of the polygenic nature of resistance and the associated resistance mechanisms. This includes examining resistance both within and among \u003cem\u003eStriga\u003c/em\u003e race structures, as well as understanding the nature of interaction effects between \u003cem\u003eStriga\u003c/em\u003e ecotypes and sorghum genotypes and different hosts (Qiu et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Rispail et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Scholes and Press \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). In Ethiopia, released resistant varieties demonstrate considerable adaptability, particularly in \u003cem\u003eStriga\u003c/em\u003e infested areas. However, there is limited concrete information regarding the genetic variation among sorghum varieties in \u003cem\u003eStriga\u003c/em\u003e resistance, the effects of host parasite interactions, and the virulence levels of major \u003cem\u003eStriga\u003c/em\u003e ecotypes on different sorghum varieties, especially given the diverse \u003cem\u003eStriga\u003c/em\u003e populations across Ethiopian ecotypes (Welsh and Mohamed \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Moreover, utilizing known improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties enhances our understanding of how sorghum interacts with different \u003cem\u003eStriga\u003c/em\u003e ecotypes and the virulence levels of the parasite. This information is critical for advancing future \u003cem\u003eStriga\u003c/em\u003e breeding strategies and selecting appropriate varieties for wide \u003cem\u003eStriga\u003c/em\u003e ecotypes. Therefore, to assess the genetic variation of \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties in response to five distinct Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes, to determine the virulence levels of \u003cem\u003eStriga\u003c/em\u003e ecotypes against seven resistant sorghum varieties, and to investigate the nature of their interaction effects, three \u003cem\u003eStriga\u003c/em\u003e resistance traits were collected from a controlled pot experiment.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eExperimental location and materials\u003c/h2\u003e\n \u003cp\u003eThe pot experiment was conducted in 2024 at the Debre Berhan Agricultural Research Center in Debre Berhan. Seeds of seven \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties and two susceptible checks were obtained from the National Sorghum Research Program at the Melkasa Agricultural Research Center of the Ethiopian Institute of Agricultural Research (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eList of \u003cem\u003eStriga\u003c/em\u003e resistant and susceptible sorghum varieties used in the study\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eStriga\u003c/em\u003e resistance reaction\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReferences\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbshir\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Belay et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e; Teka \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBerhan\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Abate et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; Belay et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e; Teka \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBTx623\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFramida\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Ahmed et al. \u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e; Muchira et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGobiye\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Abate et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; Belay et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e; Teka \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Mbuvi et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; Muchira et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSRN-39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResistant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Kawa et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e; Temesgen \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTeshale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSusceptible\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Mulatu \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e; Temesgen \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eShanqo Red (SQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSusceptible\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Gobena et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; Kawa et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cstrong\u003eStriga hermonthica\u003c/strong\u003e \u003cstrong\u003eseed collection\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe \u003cem\u003eStriga hermonthica\u003c/em\u003e seeds used in this study were collected from severely infested sorghum fields across five distinct geographical locations in Ethiopia during the 2022 cropping season. Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e describes the geographical locations of the \u003cem\u003eStriga\u003c/em\u003e collection sites. Healthy, intact \u003cem\u003eStriga\u003c/em\u003e plants with no visible flowers or only the topmost flowers remaining were carefully collected from extensively infested areas using the methods described by Berner et al. (\u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e). The harvested \u003cem\u003eStriga\u003c/em\u003e plants were spread out to dry on a large polyethylene sheet in a well ventilated, covered space. After 20 days of drying, during which shattered \u003cem\u003eStriga\u003c/em\u003e seeds fell onto the sheet, the dried plants were carefully transferred to another polyethylene sheet, with the heads gently tapped to encourage seed shedding. The threshed \u003cem\u003eStriga\u003c/em\u003e seeds from both sheets were then collected into separate containers and sieved through 250 and 150 micron open sieves. Finally, pure\u0026nbsp;\u003cem\u003eStriga\u003c/em\u003e seeds were placed in labeled plastic containers and stored in a refrigerator at the Holeta Agricultural Biotechnology Research Center.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eThe description of the geographical locations of the \u003cem\u003eStriga\u003c/em\u003e collection site\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLocation\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eZone\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAltitude (m.a.s.l)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLocation\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAssosa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAssosa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1300\u0026ndash;1570\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003csup\u003eo\u003c/sup\u003e 04\u0026prime;\u0026prime; N, 34\u003csup\u003eo\u003c/sup\u003e 31\u0026prime;\u0026prime; E\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBabile\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEast Harerge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1646.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e09\u003csup\u003eo\u003c/sup\u003e 13\u0026prime; 19\u0026prime;\u0026prime; N, 42\u003csup\u003eo\u003c/sup\u003e 19\u0026prime; 47\u0026prime;\u0026prime; E\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFedis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEast Harerge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1055.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e08\u003csup\u003eo\u003c/sup\u003e 49\u0026prime; 43\u0026prime;\u0026prime; N, 42\u003csup\u003eo\u003c/sup\u003e 00\u0026prime; 45\u0026prime;\u0026prime; E\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNorth Wolo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1476.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u0026deg; 7\u0026prime; 11.52\u0026prime;\u0026prime; N, 39\u0026deg; 37\u0026prime; 26.36\u0026prime;\u0026prime; E\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eShewa Robit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNorth Shoa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1235\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e09\u003csup\u003eo\u003c/sup\u003e 59\u0026prime; 53\u0026Prime; N, 39\u003csup\u003eo\u003c/sup\u003e 53\u0026prime; 53\u0026Prime; E\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cstrong\u003eSurface sterilization, preconditioning, and infestation of\u003c/strong\u003e \u003cstrong\u003eStriga\u003c/strong\u003e \u003cstrong\u003eseeds\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe procedure described by Taylor et al. (\u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e) was used for \u003cem\u003eStriga\u003c/em\u003e seed surface sterilization and conditioning. A measured amount of viable \u003cem\u003eStriga\u003c/em\u003e seeds from each ecotype was soaked in a separate flask containing 20% commercial bleach for ten minutes, followed by three rinses with autoclaved distilled water. The sterilized \u003cem\u003eStriga\u003c/em\u003e seeds were then incubated at 30\u0026deg;C in the dark for 14 days. Conical pots with a volume of 5 liters, a height and top diameter of 20 cm, and a bottom diameter of 8 cm were selected for the experiment. Three kilograms of a 1:3 sand to soil mixture were placed into each pot. Before planting, approximately 7,500 (0.077 g) preconditioned \u003cem\u003eStriga\u003c/em\u003e seeds were added to each pot containing the 3 kg sand/soil mixture and thoroughly mixed.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eSorghum planting and growth monitoring under greenhouse conditions\u003c/h3\u003e\n\u003cp\u003eThree or four healthy sorghum seeds were sown in a 2\u0026ndash;3 cm hole made in the center of each pot. After twelve days, one healthy and vigorous seedling per pot was retained, and the others were carefully thinned out. For this study, the fertigation method described by Berner et al. (\u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e) for \u003cem\u003eStriga\u003c/em\u003e screening under controlled conditions was employed. Each pot received 0.113 g of NPS fertilizer at the time of thinning, followed by 0.052 g of nitrogen in the form of urea seven days later. During the first five weeks, each pot was watered with approximately 30 ml daily. For the remainder of the experiment, each pot continued to receive the same volume of water at daily intervals.\u003c/p\u003e\n\u003ch3\u003eData collection\u003c/h3\u003e\n\u003cp\u003eThree \u003cem\u003eStriga\u003c/em\u003e resistance related traits were measured ten weeks after sowing sorghum seeds: attached and emerging \u003cem\u003eStriga\u003c/em\u003e count (SC), \u003cem\u003eStriga\u003c/em\u003e length (SL), and dry biomass (SBM) (Joel et al. 2018; Kaubi \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e; Kavuluko et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mbuvi et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). \u003cem\u003eStriga\u003c/em\u003e seedling attachments collected from each pot were counted and photographed on 90 mm Petri dishes. Dry \u003cem\u003eStriga\u003c/em\u003e biomass was determined after the seedlings were oven dried for 24 hours at 60\u0026deg;C. Finally, the length of the attached \u003cem\u003eStriga\u003c/em\u003e seedlings was measured using ImageJ v.1.45 software (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://imagej.net/ij/download.html\u003c/span\u003e\u003c/span\u003e), and the average length per pot was calculated (Joel et al. 2018).\u003c/p\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical analysis\u003c/h2\u003e\n \u003cp\u003eA combined three way analysis of variance (ANOVA) for three \u003cem\u003eStriga\u003c/em\u003e related quantitative traits was conducted using data from a randomized complete block design with factorial arrangements, comprising four replications, and carried out over two distinct seasons under controlled conditions. This analysis was performed using the R function fat3.rbd() from the ExpDes package (Ferreira et al. \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e). The significance of the mean squares for the main and interaction effects was assessed using least significant difference (LSD) tests at a P\u0026thinsp;\u0026le;\u0026thinsp;0.05 probability level. The virulence levels of the five Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes on resistant sorghum varieties alone, and including the two checks, were graphically summarized using SRplot, A free online platform for data visualization and graphing (Tang et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eUsing five Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes, this study evaluated the genetic variability of seven improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties, focusing on three \u003cem\u003eStriga\u003c/em\u003e related traits. The response of different sorghum varieties to \u003cem\u003eStriga\u003c/em\u003e infestation was assessed by measuring the total count, mean length, and dry biomass of \u003cem\u003eStriga\u003c/em\u003e attached to the root zone of each sorghum variety (Kaubi \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e; Mbuvi et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). Significant genotypic variation was observed among the \u003cem\u003eStriga\u003c/em\u003e resistant varieties across all three traits. Accordingly, there was significant genotypic variation between \u003cem\u003eStriga\u003c/em\u003e resistant varieties in all three traits. SC (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), SL (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and SBM (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) were the three \u003cem\u003eStriga\u003c/em\u003e related parameters to which the resistance of varieties varied significantly on the five Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). Furthermore, when including the two standard checks, \u0026quot;SQR\u0026quot; and \u0026ldquo;Teshale,\u0026rdquo; in the analysis alongside the seven improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties, the significant genotypic variations in all three traits remained consistent (Supplementary Table \u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e). Conversely, in both analyses, the tested \u003cem\u003eStriga\u003c/em\u003e ecotypes did not exhibit a significant effect on any of the measured traits (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e and Supplementary Tables S1).\u003c/p\u003e\n\u003cp\u003eEmphasizing the consequences of interactions, the two way interaction effects of variety by ecotype had a significant influence on SC and SBM in both analyses, including and excluding the standard checks traits (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e and Supplementary Tables S1). However, a notable variety by ecotype interaction effect on SL was observed when evaluating the seven improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties without the two susceptible checks. This strong variety by ecotype interaction suggests that the responses of resistant varieties to the three parameters were significantly affected by the varying \u003cem\u003eStriga\u003c/em\u003e ecotypes. A strong and significant three way interaction effect was detected for SBM in both analyses, with and without the standard checks (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Therefore, the impact of these interactions on SBM should be examined across different environmental levels. Consequently, using the seven improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties, this study primarily focused on the two way interaction effects of\u0026nbsp;\u003cem\u003eStriga\u003c/em\u003e ecotypes and varieties on SC and SL.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eCombined three way ANOVA for seven improved resistant varieties across five \u003cem\u003eStriga\u003c/em\u003e ecotypes and two seasons on SC, SL, and SBM, analysis of ecotypes inside each level of varieties for SC and SL, and analysis of varieties within each level of ecotype for SC and SL.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSource of Variations\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eDF\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eMean Squares\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSC\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSL\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSBM\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e131.57***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.45***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.68*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e28.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEnvironment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e65.09*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.32**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e54.69***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.48*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.61**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Environment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.02*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x Environment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype x Environment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.73***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety Abshir\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e58.84**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10.17*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety Berhan\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e29.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety BTx623\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10.15*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety Framida\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40.35*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10.09*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety Gobiye\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e99.9***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety N-13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEcotype x variety SRN39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e93.94***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype Assosa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42.37*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.11*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype Babile\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e52.91**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype Fedis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34.37*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.94*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype Kobo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e118.41***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14.05***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety x Ecotype S/Robit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e102.28***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e\u003cem\u003e***, **, * indicate significant at 0.1%, 1%, and 5% probability level respectively, SC: Striga count, SL: Striga Length, and SBM: Striga Biomass\u003c/em\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe analysis of ecotypes within each variety level is presented in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, which shows that the interaction effects of ecotypes within each variety level were significant. Specifically, the interaction effects of ecotypes with the varieties Abshir (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), Framida (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), Gobiye (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and SRN-39 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) on SC were significant. Similarly, the average SL of Abshir, BTx623, and Framida was influenced by their interactions with different \u003cem\u003eStriga\u003c/em\u003e ecotypes.\u003c/p\u003e\n\u003cp\u003eVariety Abshir exhibited higher SC with ecotypes from Assosa (6.13) and Kobo (9.75), whereas the number of attached \u003cem\u003eStriga\u003c/em\u003e on variety Gobiye was lower for ecotypes from Assosa (2.50) and Kobo (2.63). Additionally, variety SRN-39 showed a high mean SC on the ecotype from Babile (9.38), while variety Framida exhibited significantly high and low mean SC on ecotypes from Assosa (3.75) and Fedis (4.75), respectively (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e and Supplementary Table S2). The mean SL of variety Abshir was significantly lower on ecotypes from Babile (0.87 cm) and Fedis (1.22 cm). In contrast, sorghum variety BTx623 had significantly higher mean SL on ecotypes from Fedis (3.6 cm), and variety Framida showed higher mean SL on ecotypes from Assosa (2.17 cm) and Kobo (3.76 cm) (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e and Supplementary Table S3). Consequently, the mean SC and SL responses of ecotypes within each variety confirmed the immune response of certain varieties to the tested \u003cem\u003eStriga\u003c/em\u003e ecotypes, such as Abshir for ecotypes from Babile, Fedis, and S/Robit; BTx623 for ecotypes from Kobo and S/Robit; and Gobiye for ecotypes from Assosa and Kobo. Furthermore, the strong immune response of N13 was confirmed across all tested \u003cem\u003eStriga\u003c/em\u003e populations. Overall, all examined resistant varieties, except Berhan and N13, had a significant effect on the mean performance of ecotypes for SC and SL (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003cp\u003eThe virulence levels of five Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes were investigated by analyzing their interaction effects with seven improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties for SC and SL. The analysis of the seven improved resistant varieties within each ecotype level for SC and SL (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e) showed that, under the \u003cem\u003eStriga\u003c/em\u003e ecotypes Assosa (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), Babile (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01), Fedis (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), Kobo (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and S/Robit (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), the number of \u003cem\u003eStriga\u003c/em\u003e attached to the root zone of the varieties varied significantly. Similarly, for the sorghum varieties, performance differences in the length of attached \u003cem\u003eStriga\u003c/em\u003e were significant under the \u003cem\u003eStriga\u003c/em\u003e ecotypes Assosa (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), Fedis (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and Kobo (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eThe analysis of the varieties\u0026apos; mean SC and SL within each ecotype (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e) revealed that the Assosa \u003cem\u003eStriga\u003c/em\u003e ecotype exhibited a significantly higher number of \u003cem\u003eStriga\u003c/em\u003e attachments on the varieties Abshir (6.13) and BTx623 (6.88), as well as the greatest SL on Abshir (3.65 cm) and Framida (2.17 cm). Similar to the varieties Berhan and Framida, the \u003cem\u003eStriga\u003c/em\u003e ecotype from Babile showed substantially higher attachments to variety SRN-39 (9.38). \u003cem\u003eStriga\u003c/em\u003e ecotype Fedis on variety BTx623 (3.50 and 3.60 cm) and Gobiye (7.38 and 1.98 cm), and Kobo on variety Abshir (9.75 and 2.69 cm) and Framida (9.63 and 3.76 cm) were found to have significantly more attachments and longer mean lengths. The \u003cem\u003eStriga\u003c/em\u003e ecotype from S/Robit severely affected variety Gobiye (10.88). The analysis of the nine varieties (seven resistant and two susceptible varieties) means SC and SL within each ecotype further supports the variation in virulence levels of major Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes on the developed sorghum varieties (Supplementary Tables S4 and S5)\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eContinuous screening of sorghum genotypes and identifying the most resistant varieties under uniform \u003cem\u003eStriga\u003c/em\u003e infestation conditions is crucial to mitigating the increasingly severe impact of \u003cem\u003eStriga\u003c/em\u003e on sorghum production. The mean number, mean length, and dry biomass of \u003cem\u003eStriga\u003c/em\u003e growing on the roots of each of the sorghum varieties were used to classify their reaction to the parasite. Resistant varieties exhibited the fewest attachments, the shortest \u003cem\u003eStriga\u003c/em\u003e length, and the lowest dry biomass on their roots (Joel et al. 2018; Kavuluko et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). All resistant sorghum varieties studied exhibited some level of successful parasite attachment to the roots, as complete resistance to \u003cem\u003eStriga\u003c/em\u003e has not been identified in cultivated sorghum varieties (Gurney et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). Our pot experiment revealed that released \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties respond differently to \u003cem\u003eStriga\u003c/em\u003e infection on the three resistance traits. This variation suggests that some varieties may possess more effective resistance mechanisms against the parasite, while others may lack such defenses. Similar differences in resistance responses among sorghum varieties under \u003cem\u003eStriga\u003c/em\u003e infested conditions have been reported by Abate et al. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), Ayana (2019), Fisseha et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), Mamo et al. (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), and Mbuvi et al. (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe primary focus of this study was the observed two way interaction effects between \u003cem\u003eStriga\u003c/em\u003e ecotypes and sorghum varieties on SC and SL, which determine the virulence levels of \u003cem\u003eStriga\u003c/em\u003e ecotypes on different sorghum varieties and the resistance responses of various sorghum varieties to different \u003cem\u003eStriga\u003c/em\u003e ecotypes. The presence of an interaction effect suggests that different sorghum varieties vary in their capacity to stimulate germination or withstand infections from different \u003cem\u003eStriga\u003c/em\u003e ecotypes, and vice versa (Musimwa \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Haussmann et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). This indicates that some sorghum genotypes exhibit ecotype specific resistance, while others demonstrate strong and broad resistance across multiple ecotypes. According to Huang et al. (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), the interaction between \u003cem\u003eStriga\u003c/em\u003e populations and varieties significantly influences the success of parasites attaching to hosts. Therefore, this interaction effect has important implications for identifying resistant genotypes for breeding purposes, suggesting that breeding \u003cem\u003eStriga\u003c/em\u003e resistant sorghum may be more complex than it initially appears. Similar studies have also demonstrated the interaction effects between the host and \u003cem\u003eStriga\u003c/em\u003e populations, which determine host resistance and parasite virulence (Bozkurt et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Haussmann et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Huang et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Rodenburg et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eStrong interactions reflect the presence of distinct resistance responses to specific \u003cem\u003eStriga\u003c/em\u003e populations and the complexity of \u003cem\u003eStriga\u003c/em\u003e virulence toward particular sorghum (Bozkurt et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). An ecotype study within each variety revealed that both the length of \u003cem\u003eStriga\u003c/em\u003e attachments on Abshir, BTx623, and Framida varieties, and the number of \u003cem\u003eStriga\u003c/em\u003e attachments on Abshir, Framida, Gobiye, and SRN-39 varieties, were significantly influenced by changes in \u003cem\u003eStriga\u003c/em\u003e ecotype. The responses of these varieties to different \u003cem\u003eStriga\u003c/em\u003e ecotypes affect both the total number and length of \u003cem\u003eStriga\u003c/em\u003e attachments near their root zones. Beyond differences in low \u003cem\u003eStriga\u003c/em\u003e germination stimulation (Yohannes et al. \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), the varied responses of genotypes to infection by different \u003cem\u003eStriga\u003c/em\u003e populations may also result from differences in resistance mechanisms among resistant genotypes (Muchira et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Comparatively, the mean performance of the Abshir variety confirmed its stronger resistance to \u003cem\u003eStriga\u003c/em\u003e ecotypes Babile and Fedis. Framida exhibited superior resistance to \u003cem\u003eStriga\u003c/em\u003e ecotypes Assosa and Fedis. Gobiye\u0026rsquo;s resistance was more pronounced against ecotypes Assosa and Kobo than others. SRN-39 and BTx623 showed stronger resistance reactions across all \u003cem\u003eStriga\u003c/em\u003e populations except Babile and Fedis, respectively. This inconsistency suggests that when varieties are exposed to different \u003cem\u003eStriga\u003c/em\u003e populations, their genetic potential for resistance may include traits that either enhance strong resistance or confer partial resistance to \u003cem\u003eStriga\u003c/em\u003e. Similarly, Haussmann et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e) demonstrated an entry-by-country interaction effect, indicating that entries identified as \u003cem\u003eStriga\u003c/em\u003e resistant in Kenya may not be resistant in Mali. Overall, the interaction effect highlights significant variation in \u003cem\u003eStriga\u003c/em\u003e resistance, revealing that sorghum varieties from distinct geographic regions respond differently to \u003cem\u003eStriga\u003c/em\u003e infestation. Sorghum variety development and recommendations targeted at specific \u003cem\u003eStriga\u003c/em\u003e ecotypes may not always be effective due to the high genetic variability among \u003cem\u003eStriga\u003c/em\u003e populations in Ethiopia (Welsh and Mohamed \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). This genetic diversity enables the parasite to evolve and adapt to changing environmental conditions (Unachukwu et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), often overcoming the resistance of varieties, especially when new \u003cem\u003eStriga\u003c/em\u003e races infest the area (Rispail et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe total number of \u003cem\u003eStriga\u003c/em\u003e attachments in the root zones of sorghum varieties varied significantly when infected with \u003cem\u003eStriga\u003c/em\u003e ecotypes from Assosa, Babile, Fedis, Kobo, and S/Robit. Similarly, infection by \u003cem\u003eStriga\u003c/em\u003e ecotypes from Assosa, Fedis, and Kobo had a significant impact on the length of the attached \u003cem\u003eStriga\u003c/em\u003e across different sorghum varieties. According to Bozkurt et al. (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), the strong interaction effect indicates distinct variations in \u003cem\u003eStriga\u003c/em\u003e virulence toward specific sorghum varieties. The variety analysis at each ecotype level further confirms the presence of variable virulence levels of \u003cem\u003eStriga\u003c/em\u003e ecotypes on the tested sorghum varieties (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Rodenburg et al. (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) also reported variation in \u003cem\u003eStriga\u003c/em\u003e virulence across species and ecotypes. \u003cem\u003eStriga\u003c/em\u003e populations in Ethiopia exhibit a high degree of genetic diversity, with geographic distribution playing a crucial role in shaping this diversity (Welsh and Mohamed \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The extensive genetic diversity of \u003cem\u003eStriga\u003c/em\u003e is driven by the parasite\u0026rsquo;s boundless variability, exceptionally high seed production and fecundity, and the geographic distance of ecotypes (Ejeta et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Welsh and Mohamed \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2011\u003c/span\u003e), all of which determine their virulence and the effectiveness of host resistance (Haussmann et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Consequently, the distinct geographic origins of the five \u003cem\u003eStriga\u003c/em\u003e populations likely contribute to the observed variability in \u003cem\u003eStriga\u003c/em\u003e virulence against released \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties.\u003c/p\u003e\u003cp\u003eThe mean number and length of attached \u003cem\u003eStriga\u003c/em\u003e plants surrounding the root zone of improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties within each \u003cem\u003eStriga\u003c/em\u003e ecotype were used to determine the virulence levels of the five \u003cem\u003eStriga\u003c/em\u003e ecotypes. For the seven improved \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties, the virulence level of each evaluated Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotype varied significantly. This study showed that the Assosa ecotype exhibited greater virulence toward the varieties BTx623, Framida, and Abshir, while demonstrating reduced virulence against N13 and SRN-39. The Babile ecotype was less virulent to N13 and Abshir but more virulent to SRN-39, Framida, and Berhan. The Fedis ecotype was significantly less virulent to N13 and SRN-39 compared to its effects on Gobiye, Berhan, Framida, and BTx623. The Kobo ecotype was less virulent to Berhan, BTx623, Gobiye, N13, and SRN-39, but more virulent to Abshir and Framida. The final tested \u003cem\u003eStriga\u003c/em\u003e ecotype, S/Robit, showed significantly higher virulence toward Gobiye and lower virulence toward N13, BTx623, and SRN-39. According to Haussmann et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e), the interaction of \u003cem\u003eStriga\u003c/em\u003e ecotype and host variety influences \u003cem\u003eStriga\u003c/em\u003e resistance; they also observed that \u003cem\u003eStriga\u003c/em\u003e ecotypes highly virulent to one variety may not be virulent to another. Even if \u003cem\u003eStriga\u003c/em\u003e ecotypes had varying effects on different varieties, this study found that every ecotype exhibited a lower virulence towards variety N13 and SRN-39 while having higher virulence towards variety Framida.\u003c/p\u003e\u003cp\u003eThe development of resistant sorghum varieties has proven to be quite challenging for plant breeders due to the varying resistance responses of sorghum genotypes across different ecotypes and the differing infection levels of \u003cem\u003eStriga\u003c/em\u003e populations on these genotypes. Consequently, cultivated sorghum varieties are not completely resistant to \u003cem\u003eStriga\u003c/em\u003e (Gurney et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). In this study, varieties N13 and SRN-39 consistently exhibited higher resistance across all \u003cem\u003eStriga\u003c/em\u003e ecotypes. Other studies also demonstrate that N13 (Joel et al. 2018; Mohamed et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and SRN-39 (Ezeaku and Gupta \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Mohamed et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Muchira et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) effectively defend against various \u003cem\u003eStriga\u003c/em\u003e infections. The resistance mechanisms in N13 and SRN-39 are reported to involve low germination stimulation and a mechanical barrier to \u003cem\u003eStriga\u003c/em\u003e penetration, attributed to their high lignin and suberin deposition, respectively. Understanding these resistance mechanisms facilitates gene pyramiding (Muchira et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The consistent resistance and distinct mechanisms of these two sorghum varieties may aid \u003cem\u003eStriga\u003c/em\u003e resistance breeding programs and enhance \u003cem\u003eStriga\u003c/em\u003e management efforts. Furthermore, knowledge of how \u003cem\u003eStriga\u003c/em\u003e ecotypes differ in virulence simplifies the identification of resistance genes capable of producing genotypes resistant to multiple ecotypes (Unachukwu et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Overall, this study provides crucial information for mapping the N13 and SRN-39 genes in adapted high yielding genotypes and screening them under diverse \u003cem\u003eStriga\u003c/em\u003e infected conditions. Evaluating breeding materials across multiple environments against different host specific \u003cem\u003eStriga\u003c/em\u003e populations is essential for selecting stable resistance (Haussmann et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e).\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe genetic variation of sorghum varieties, the interaction effect of varieties with \u003cem\u003eStriga\u003c/em\u003e ecotypes, and the virulence differences of five major Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes for the resistance varieties were assessed in this activity. The significant interaction effect of major Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes with resistant sorghum varieties articulates the complexity of \u003cem\u003eStriga\u003c/em\u003e\u0026rsquo;s virulence. The result of this study revealed that certain \u003cem\u003eStriga\u003c/em\u003e ecotypes showed higher virulence levels to some of the sorghum varieties but lesser to the others; similarly, certain sorghum varieties showed more resistance or susceptibility to each of the ecotypes. Such strong virulence level variation highlights the importance of ecotypes in determining varietal selection for \u003cem\u003eStriga\u003c/em\u003e resistance and developing targeted breeding strategies that enhance resistance to \u003cem\u003eStriga\u003c/em\u003e infestations. The clear differences in resistance reaction are shown by the contrasting behaviors of Framida and N13 across all ecotypes. Varieties N13 and SRN-39 showed a consistently higher resistance reaction across multiple ecotypes, which may facilitate the strategic pyramiding of different resistance genes within identified high-yielding genotypes, and researchers can enhance breeding programs aimed at developing \u003cem\u003eStriga\u003c/em\u003e-resistant sorghum varieties. One of the main factors influencing population structure (virulence) in Ethiopia is the wide geographic range of sorghum-growing locations. Therefore, exhaustive studies on the genetic variability of Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes facilitate the development of durable resistant genotypes. Furthermore, combining controlled testing and multi-ecotype evaluation of genotypes with multiple resistance mechanisms may serve as an effective sorghum breeding strategy for \u003cem\u003eStriga\u003c/em\u003e-affected farmers in Ethiopia.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eAATF: Africa Agricultural Technology Foundation\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eISM: Integrated \u003cem\u003eStriga\u003c/em\u003e management\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSBM: \u003cem\u003eStriga\u0026nbsp;\u003c/em\u003eBiomass\u003c/p\u003e\n\u003cp\u003eSC: \u003cem\u003eStriga\u003c/em\u003e Count\u003c/p\u003e\n\u003cp\u003eSL: \u003cem\u003eStriga\u003c/em\u003e Length\u003c/p\u003e\n\u003cp\u003eSSA: Sub Saharan Africa\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was funded by\u0026nbsp;the Amhara Agricultural Research Institute (ARARI) and the National Sorghum Improvement Program, Melkasa Agricultural Research Center, Ethiopia Institute of Agricultural Research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no relevant financial or non-financial interests to release.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval has been given for the software, as well as previous studies we used to refer to and discuss in this publication, and the manuscript acknowledges all the works.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent\u003c/strong\u003e\u003cstrong\u003e:\u0026nbsp;\u003c/strong\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dataset generated during the experiment is available from the corresponding author on reasonable request. The analyzed data supporting the texts and figures of this manuscript are included in supplementary information files.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization\u003cem\u003e\u0026nbsp;and design of the experiment were performed by Abiy Legesse, Habte Nida, and Alemu Tirfesa. Material preparation, execution of pot experiments, and data collection were executed by Abiy Legesse, Hewan Demissie, and Taye Tesema. Data interpretation of results and preparation of the manuscript were done by Abiy Legesse. The first draft of the manuscript was written by Abiy Legesse, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorresponding author:\u0026nbsp;\u003c/strong\u003eCorrespondence to Abiy Legesse Kibebe\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAATF (Africa Agricultural Technology Foundation) (2011) Feasibility Study on \u003cem\u003eStriga\u003c/em\u003e Control in Sorghum. Africa Agricultural Technology Foundation, Nairobi\u003c/li\u003e\n\u003cli\u003eAbate M, Hussien T, Bayu W, Reda F (2017) Screening of Ethiopian sorghum (\u003cem\u003eSorghum bicolor\u003c/em\u003e (L.) Moench) landraces for their performance in \u003cem\u003eStriga hermonthica \u003c/em\u003e(Del.) Benth infested conditions. Plant Breeding. https://doi.org/10.1111/pbr.1251\u003c/li\u003e\n\u003cli\u003eAhmed A, Elsafy M, Zhourghane A, Abdalla AA, Abreha KB, Geleta M, Rahmatov M, Abdelhalim TS (2024) Exploring the genetic variability of Sudanese wild sorghum (\u003cem\u003eSorghum bicolor\u003c/em\u003e (L.) Moench) germplasm for post-attachment \u003cem\u003eStriga hermonthica\u003c/em\u003e resistance mechanisms using single sequence repeat (SSR) primers. Genetic Resources and Crop Evolution 72:4583\u0026ndash;4595. https://doi.org/10.1007/s10722-024-02230-w\u003c/li\u003e\n\u003cli\u003eAyana TT, Bantte K, Tadesse T (2019) Evaluation of Ethiopian Sorghum [\u003cem\u003eSorghum bicolor\u003c/em\u003e (L.) Moench] Landraces: Low germination stimulant genotypes for \u003cem\u003eStriga hermonthica \u003c/em\u003eresistance under field conditions. Advanced Crop Science Technology 7:444. http://dx.doi.org/10.4172/2329-8863.1000444\u003c/li\u003e\n\u003cli\u003eBelay F, Firew M, Taye T (2021) Univariate stability analysis and relationship among parameters for grain yield of \u003cem\u003eStriga\u003c/em\u003e-resistant sorghum hybrids in Ethiopia. Open Journal of Plant Science 6:069-081. DOI: https://dx.doi.org/10.17352/ojps.000036\u003c/li\u003e\n\u003cli\u003eBerner DK, Winslow MD, Awad AE, Cardwell KF, Mohan Raj DR, Kim SK (1997) \u003cem\u003eStriga \u003c/em\u003eResearch Methods Manual, 2\u003csup\u003end\u003c/sup\u003e edn. International Institute of Tropical Agriculture PMB 5320, Ibadan, Nigeria\u003c/li\u003e\n\u003cli\u003eBozkurt ML, Muth P, Parzies HK, Haussmann BIG (2015) Genetic diversity of East and West African \u003cem\u003eStriga hermonthica\u003c/em\u003e populations and virulence effects on a contrasting set of sorghum cultivars. Weed Research 55:71-81. https://doi.org/10.1111/wre.12117\u003c/li\u003e\n\u003cli\u003eDossa EN, Shimelis H, Shayanowako AIT, Laing MD (2023) A meta-analysis of the effects of \u003cem\u003eStriga \u003c/em\u003econtrol methods on maize, sorghum, and major millet production in sub-Saharan Africa. Crop Science 63:460-479. https://doi.org/10.1002/csc2.20889\u003c/li\u003e\n\u003cli\u003eEarecho MK, Nebiyu E, Alemu H (2024) Evaluation of Western Ethiopian sorghum landraces for resistance to \u003cem\u003eStriga hermonthica\u003c/em\u003e (Del.) Benth. Advanced Crop Science Technology 12:690\u003c/li\u003e\n\u003cli\u003eEjeta G (2007a) Breeding for \u003cem\u003eStriga\u003c/em\u003e resistance in sorghum: Exploitation of an intricate host-parasite biology. Crop Science 47:216-227. https://doi.org/10.2135/cropsci2007.04.0011IPBS\u003c/li\u003e\n\u003cli\u003eEjeta G (2007b) The \u003cem\u003eStriga\u003c/em\u003e Scourge in Africa: A Growing Pandemic. In: Ejeta G, Gressel J. Integrating new technologies for \u003cem\u003eStriga\u003c/em\u003e control towards ending the witch-hunt. World Scientific Publishing Co Pte Ltd, Singapore, PP 3\u0026ndash;16\u003c/li\u003e\n\u003cli\u003eEjeta G, Patrick J, Mohamed RA (2007) Dissecting a complex trait into simpler components for effective breeding of sorghum with a high level of \u003cem\u003eStriga\u003c/em\u003e resistance. In: Ejeta G, Gressel J. Integrating new technologies for \u003cem\u003eStriga\u003c/em\u003e control towards ending the witch-hunt. World Scientific Publishing Co Pte Ltd, Singapore, PP 87\u0026ndash;98\u003c/li\u003e\n\u003cli\u003eEmechebe AM, Ellis-Jones J, Schulz S, Chikove D, Douthwaite B, Kureh I, Tarawali G, Hussaini MA, Kormawa P, Sanni A (2004) Farmers\u0026rsquo; perception of the \u003cem\u003eStriga\u003c/em\u003e problem and its control in northern Nigeria. Expl Agric 40:215\u0026ndash;232\u003c/li\u003e\n\u003cli\u003eEzeaku IE, Gupta SC (2004) Development of sorghum populations for resistance to \u003cem\u003eStriga hermonthica\u003c/em\u003e in the Nigerian Sudan Savanna. African Journal of Biotechnology 3:324\u0026ndash;29. https://doi.org/10.5897/AJB2004.000-2059\u003c/li\u003e\n\u003cli\u003eFerreira EB, Cavalcanti PP, Nogueira DA (2014) ExpDes: An R package for Analysis of Variance (ANOVA) and experimental designs. Applied Mathematics 5:2952\u0026ndash;2958. http://dx.doi.org/10.4236/am.2014.519280\u003c/li\u003e\n\u003cli\u003eFisseha W, Teshome K, Tarekegn F (2023) Yield performance and stability evaluation of \u003cem\u003eStriga\u003c/em\u003e-resistant sorghum (\u003cem\u003eSorghum bicolor \u003c/em\u003e[L.] Moench). Journal of Plant Breeding and Crop Science 15:90\u0026ndash;98. https://doi.org/10.5897/JPBCS2022.0998\u003c/li\u003e\n\u003cli\u003eGethi JG, Smith ME, MitchelL\u0026agrave; SE, Kresovich\u0026agrave; S (2005) Genetic diversity of \u003cem\u003eStriga hermonthica \u003c/em\u003eand \u003cem\u003eStriga asiatica\u003c/em\u003e populations in Kenya. Weed Research 45:64\u0026ndash;73. http://dx.doi.org/10.1111/j.1365-3180.2004.00432.x\u003c/li\u003e\n\u003cli\u003eGobena D, Mahdere S, Patrick JR, Carolien R, Harro B, Satish K, Tesfaye M, Gebisa E (2017) A mutation in the sorghum low germination stimulant alters strigolactones and causes \u003cem\u003eStria\u003c/em\u003e resistance. Proc Natl Acad Sci 114:4471\u0026ndash;4476. https://doi.org/10.1073/pnas.1618965114\u003c/li\u003e\n\u003cli\u003eGurney AL, Press MC, Scholes JD (2002) Can wild relatives of sorghum provide new sources of resistance or tolerance against \u003cem\u003eStriga\u003c/em\u003e species? Weed Research 42:317\u0026ndash;324. http://dx.doi.org/10.1046/j.1365-3180.2002.00291.x\u003c/li\u003e\n\u003cli\u003eHaussmann B, Hess D, Reddy B, Mukuru S, Kayentao M, Welz H, Geiger H (2001) Pattern analysis of genotype \u0026times; environment interaction for \u003cem\u003eStriga\u003c/em\u003e resistance and grain yield in African sorghum trials. Euphytica 122:297\u0026ndash;308. https://doi.org/10.1023/A:1012909719137\u003c/li\u003e\n\u003cli\u003eHuang K, Whitlock R, Press MC, Scholes JD (2012) Variation for host range within and among populations of the parasitic plant \u003cem\u003eStriga hermonthica\u003c/em\u003e. Heredity 108:96\u0026ndash;104. https://doi.org/10.1038/hdy.2011.52\u003c/li\u003e\n\u003cli\u003eJoel Kataka Atanda, Runo S, Muchugi A (2018) Genetic diversity and virulence of \u003cem\u003eStriga hermonthica\u003c/em\u003e from Kenya and Uganda on selected sorghum varieties. Nusantara Bioscience 10:111\u0026ndash;120. http://dx.doi.org/10.13057/nusbiosci/n100208\u003c/li\u003e\n\u003cli\u003eKaubi NH (2016) Evaluation of maize (\u003cem\u003eZea Mays\u003c/em\u003e L.) genotypes with multiple resistance to \u003cem\u003eStriga hermonthica\u003c/em\u003e (Del.) Benth and \u003cem\u003eStriga asiatica\u003c/em\u003e (L.) Kuntze. Dissertation, University of Zambia\u003c/li\u003e\n\u003cli\u003eKavuluko J, Kibe M, Sugut I, Kibet W, Masanga J, Mutinda S, Wamalwa M, Magomere T, Odeny D, Runo S (2021) GWAS provides biological insights into the mechanisms of the parasitic plant (\u003cem\u003eStriga\u003c/em\u003e) resistance in sorghum. BMC Plant Biology 21:1-15 https://doi.org/10.1186/s12870-021-03155-7\u003c/li\u003e\n\u003cli\u003eKawa D, Taylor T, Thiombiano B, Musa Z, Vahldick HE, Walmsley A, Bucksch A, Bouwmeester H, Brady SM (2021) Characterization of growth and development of sorghum genotypes with differential susceptibility to \u003cem\u003eStriga hermonthica\u003c/em\u003e. Journal of Experimental Botany 72:7970\u0026ndash;7983. https://doi.org/10.1093/jxb/erab380\u003c/li\u003e\n\u003cli\u003eMamo M, Worede F, Bantayehu M (2020) Evaluation of sorghum (\u003cem\u003eSorghum bicolor\u003c/em\u003e (L.) Moench) genotypes for \u003cem\u003eStriga\u003c/em\u003e resistance and yield and yield-related traits. Black Sea Journal of Agriculture 3:85-95\u003c/li\u003e\n\u003cli\u003eMbuvi DA, Masiga CW, Kuria E, Masanga J, Wamalwa M, Mohamed A, Odeny D, Hamza N, Timko MP, Runo S (2017) Novel sources of witchweed (\u003cem\u003eStriga\u003c/em\u003e) resistance from wild sorghum accessions. Frontiers in Plant Science 8:116. https://doi.org/10.3389/fpls.2017.00116\u003c/li\u003e\n\u003cli\u003eMohamed AH, Housley TL, Ejeta, G (2010) An in vitro technique for studying specific \u003cem\u003eStriga\u003c/em\u003e resistance mechanisms in sorghum. African Journal of Agricultural Research 5:1868-1875\u003c/li\u003e\n\u003cli\u003eMrema E, Shimelis H, Lying M, Mwadzingeni L (2020) Integrated management of \u003cem\u003eStriga hermonthica\u003c/em\u003e and \u003cem\u003eS. asiatica\u003c/em\u003e in sorghum. Australian Journal of Crop Science 14:36\u0026ndash;45. http://dx.doi.org/10.21475/ajcs.20.14.01.p1749 \u003c/li\u003e\n\u003cli\u003eMuchira N, Ngugi K, Wamalwa LN, Avosa M, Chepkorir W, Manyasa E, Nyamongo D, Odeny DA (2021) Genotypic variation in cultivated and wild sorghum genotypes in response to \u003cem\u003eStriga hermonthica\u003c/em\u003e infestation. Frontiers in Plant Science 12:671984. https://doi.org/10.3389/fpls.2021.671984\u003c/li\u003e\n\u003cli\u003eMulatu G (2020) Screening for the \u003cem\u003eStriga\u003c/em\u003e (\u003cem\u003eStriga Hermonthica\u003c/em\u003e (Del.) Benth.) resistance gene in sorghum (\u003cem\u003eSorghum Bicolor\u003c/em\u003e (L.) Moench) genotypes using Gel-Based Assay and the Lgs1 Marker in Ethiopia. Dissertation, Addis Ababa University\u003c/li\u003e\n\u003cli\u003eMusimwa C (2005) Genetic variability, host specificity, and resistance in \u003cem\u003eStriga asiatica\u003c/em\u003e-host plant interactions. Dissertation, University of Zimbabwe\u003c/li\u003e\n\u003cli\u003eParker C (2012) Parasitic Weeds: A World Challenge. Weed Science 60:269\u0026ndash;276. https://doi.org/10.1614/WS-D-11-00068.1\u003c/li\u003e\n\u003cli\u003eQiu S, Bradley JM, Zhang P, Chaudhuri R, Blaxter M, Butlin RK, Scholes JD (2022) Genome-enabled discovery of candidate virulence loci in \u003cem\u003eStriga hermonthica\u003c/em\u003e, a devastating parasite of African cereal crops. New Phytologist 236:622-638. https://doi.org/10.1111/nph.18305\u003c/li\u003e\n\u003cli\u003eRispail N, Dita MA, Gonz\u0026aacute;lez-Verdejo C, P\u0026eacute;rez-De-Luque A, Castillejo MA, Prats E, Rom\u0026aacute;n B, Jorr\u0026iacute;n J, Rubiales D (2007) Plant resistance to parasitic plants: Molecular approaches to an Old foe. New Phytologist 173:703\u0026ndash;712. https://doi.org/10.1111/j.1469-8137.2007.01980.x\u003c/li\u003e\n\u003cli\u003eRodenburg J, Bastiaans L, Weltzien E, Hess DE (2005) How can field selection for \u003cem\u003eStriga\u003c/em\u003e resistance and tolerance in sorghum be improved? Field Crops Research 93:34\u0026ndash;50. https://doi.org/10.1016/j.fcr.2004.09.004\u003c/li\u003e\n\u003cli\u003eRodenburg J, Cissoko M, Kayongo N, Dieng I, Bisikwa J, Irakiza R, Masoka I, Midega CA, Scholes JD (2017) Genetic variation and host-parasite specificity of \u003cem\u003eStriga\u003c/em\u003e resistance and tolerance in rice: the need for predictive breeding. New Phytol 214:1267-1280\u003c/li\u003e\n\u003cli\u003eScholes JD, Press MC (2008) \u003cem\u003eStriga\u003c/em\u003e infestation of cereal crops-an unsolved problem in resource-limited agriculture. Current Opinion in Plant Biology 11:180\u0026ndash;186. http://dx.doi.org/10.1016/j.pbi.2008.02.004\u003c/li\u003e\n\u003cli\u003eTang D, Chen M, Huang X, Zhang G, Zeng L, Zhang G, Zeng L, Zhang G, Wu S, Wang Y (2023) SRplot: A free online platform for data visualization and graphing. PLOS ONE 18:e0294236. https://doi.org/10.1371/journal.pone.0294236\u003c/li\u003e\n\u003cli\u003eTaylor T, Daksa J, Shimels MZ, Etalo DW, Thiombiano B, Walmsey A, Chen AJ, Bouwmeester HJ, Raaijmakers JM, Brady SM, Kawa D (2024) Evaluating mechanisms of soil microbiome suppression of \u003cem\u003eStriga\u003c/em\u003e infection in sorghum. Bio-Protocol 14:e5058. https://doi.org/10.21769/BioProtoc.5058.\u003c/li\u003e\n\u003cli\u003eTeka HB (2014) Advanced research on \u003cem\u003eStriga\u003c/em\u003e control: A review. African Journal of Plant Science 8:492-506. https://doi.org/10.5897/AJPS2014.1186\u003c/li\u003e\n\u003cli\u003eTemesgen T (2019) Review on \u003cem\u003eStriga\u003c/em\u003e distribution, infestation, and genetic potential in Ethiopian sorghum (\u003cem\u003eSorghum bicolor\u003c/em\u003e (L.) Moench). International Journal of Research Studies in Agricultural Sciences 5:23\u0026ndash;31. http://dx.doi.org/10.20431/2454-6224.0502004\u003c/li\u003e\n\u003cli\u003eTesso T, Gebisa E (2011) Integrating multiple control options enhances \u003cem\u003eStriga\u003c/em\u003e management and sorghum yield on heavily infested soils. Agronomy Journal 103:1464\u0026ndash;1471. https://doi.org/10.2134/agronj2011.0059\u003c/li\u003e\n\u003cli\u003eUnachukwu NN, Menkir A, Rabbi IY, Oluoch M, Muranaka S, Elzein A, Odhiambo G, Farombi EO, Gedil M (2017) Genetic diversity and population structure of \u003cem\u003eStriga hermonthica\u003c/em\u003e populations from Kenya and Nigeria. Weed Research 57:293-302. https://doi.org/10.1111/wre.12260\u003c/li\u003e\n\u003cli\u003eWelsh AB, Mohamed KI (2011) Genetic diversity of\u003cem\u003e Striga hermonthica\u003c/em\u003e populations in Ethiopia: Evaluating the role of geography and host specificity in shaping population structure. International Journal of Plant Sciences 172:773\u0026ndash;782. https://doi.org/10.1086/660104\u003c/li\u003e\n\u003cli\u003eYohannes T, Ngugi K, Ariga E, Abraha T, Yao N, Asami P, Ahonsi M (2016) Genotypic variation for low \u003cem\u003eStriga\u003c/em\u003e germination stimulation in sorghum (\u003cem\u003eSorghum bicolor\u003c/em\u003e (L.) Moench) landraces from Eritrea. American Journal of Plant Sciences 7:2470-2482. https://doi.org/10.4236/ajps.2016.717215\u003c/li\u003e\n\u003cli\u003eYonli D, Traore H, Van Mourik TA, Hess DE, Sereme P, Sankara P (2012) Integrated control of \u003cem\u003eStriga hermonthica\u003c/em\u003e (Del.) Benth. in Burkina Faso through host plant resistance, biocontrol, and fertilizers. International Journal of Biological and Chemical Sciences 5:1860. https://doi.org/10.4314/ijbcs.v5i5.8\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Sorghum, Striga, Ecotype, Interaction, Virulence","lastPublishedDoi":"10.21203/rs.3.rs-7448410/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7448410/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003eStriga hermonthica\u003c/em\u003e, a root hemiparasitic weed, severely limits sorghum production in Sub Saharan Africa. The use of resistant varieties is a widely adopted strategy for controlling \u003cem\u003eStriga\u003c/em\u003e. To develop durable \u003cem\u003eStriga\u003c/em\u003e resistant sorghum varieties, this study investigates the interaction effects between host and parasite, as well as the virulence levels of five Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes. A pot trial was conducted using seven resistant sorghum varieties, two susceptible checks, and five Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes. Valuable data were generated on the interaction effects between sorghum varieties and \u003cem\u003eStriga\u003c/em\u003e ecotypes based on three resistance traits: \u003cem\u003eStriga\u003c/em\u003e count, \u003cem\u003eStriga\u003c/em\u003e length, and dry \u003cem\u003eStriga\u003c/em\u003e biomass. The findings revealed variability in sorghum responses to \u003cem\u003eStriga\u003c/em\u003e infection, with significant variety by ecotype interaction effects. Notably, the virulence levels of \u003cem\u003eStriga\u003c/em\u003e ecotypes varied considerably across sorghum varieties; an ecotype highly virulent to one variety exhibited reduced virulence to another. Similarly, a sorghum variety highly resistant to one ecotype showed moderate or lower resistance to others. The variety Framida generally exhibited high levels of infection, whereas N13 demonstrated stronger resistance. Importantly, sorghum varieties N13 and SRN-39 consistently showed resistance across all tested ecotypes, making them prime candidates for strategic gene pyramiding. This study highlights the presence of interaction effects, which are critical for designing effective breeding strategies in future \u003cem\u003eStriga\u003c/em\u003e resistance improvement programs. Furthermore, comprehensive studies on the genetic variability of Ethiopian \u003cem\u003eStriga\u003c/em\u003e ecotypes will facilitate the development of durable resistant varieties.\u003c/p\u003e","manuscriptTitle":"Unveiling the Ecotype driven Virulence Heterogeneity among Major Ecotypes of the Striga hermonthica Population from Ethiopia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-02 15:28:57","doi":"10.21203/rs.3.rs-7448410/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"02ca8947-ba8b-4109-a45c-76a208f12171","owner":[],"postedDate":"September 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-10-10T15:38:34+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-02 15:28:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7448410","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7448410","identity":"rs-7448410","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}