Studies on the radiosensitivity of macropropagated corm buds of banana for the improvement of commercial triploid banana cultivars

Studies on the radiosensitivity of macropropagated corm buds of banana for the improvement of commercial triploid banana cultivars | 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 Studies on the radiosensitivity of macropropagated corm buds of banana for the improvement of commercial triploid banana cultivars Tanushree Saha, Soustav Datta, Rahi Masum Reja, Shivaji Chattopadhyay, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7207984/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 The improvement of commercial triploids of banana through conventional breeding or sexual hybridization has been very difficult due to female sterility, parthenocarpy and polyploidy. Mutation breeding appears to be a promising alternative that may induce the desired variability by altering one or more traits of a usually acceptable cultivar without retaining its original genotype unaltered. Given this background, the present study was designed to determine the radiosensitivity of corm buds and macropropagation of irradiated corms of banana cv. ‘Martaman’ (Musa AAB) with the objective of determining the lethal dose (LD50) for macropropagated buds and optimizing the radiation dose for the induction of putative mutants with one or more desired traits, such as biotic and abiotic stress tolerance or resistance, dwarfness, increased yield or improved fruit quality. Healthy decorticated corms (12–13 cm in diameter) were exposed to various doses of gamma rays ( 60 Co) at strengths of 10, 20, 30, 40, 50 and 60 Gy, with an effective dose rate of 04.348 KGy/hr. The control plants received no radiation exposure. The results revealed that the survival rate of corm buds was the lowest (19.50%) due to the irradiation dose of 60 Gy, while it was the highest (96.25%) under the control (without irradiation). The lethal dose (LD50) for the irradiated corms of banana cv. ‘Martaman’ on the basis of the 50% survival rate and number of induced primary buds per corm were 37.71 Gy and 38.95 Gy, respectively, followed by a significant decrease in growth. The growth characteristics decreased in proportion to an increase in the gamma-ray dose. The results suggest that gamma irradiation between 20-30 Gy (below the LD50) could be used to induce morphological variation among populations via the macropropagation technique and the selection of putative mutant plants, which can be used in future breeding programs for the banana cv. ‘Martaman’. Banana mutation gamma irradiation LD50 morphological effects effective dose Figures Figure 1 Figure 2 1. Introduction Bananas are among the major fruit crops for subsistence of farmers, ensuring year-round security of food and income, especially in tropical and subtropical regions. India is the largest producer of bananas, producing 31504 thousand MT from an area of 878 thousand hectares (Indian Horticulture Database, 2020 ). In West Bengal, bananas are among the most significant commercial fruit crops, and the variety ‘Martaman’ (Musa AAB) is the most important commercial variety contributing approximately 1/3rd of the total banana production in the state, and it has high market demand and price. However, commercial cultivation of this variety is remarkably impeded by several biotic and abiotic stresses, including a lack of clean and high-quality planting material, crop loss due to infestations caused by diseases ( viz. , fusarium wilt, sigatoka leaf spot), cyclone damage resulting in tall heights, falling fingers from ripe hands and bunches and a short shelf life. Given their parthenocarpic, sterile and polyploid properties, conventional breeding or sexual hybridization might have little potential for improving banana production (Uma et al ., 2016). This is a major limitation for the improvement of commercial triploids such as cvs. ‘Rasthali’ (Silk, AAB) and ‘Robusta’ (AAA) (Kumar, 2006 ). The benefit of mutation-based breeding in asexually propagated crops is that it has the potential to alter one or two characteristics without impacting the fundamental genetic background, which is frequently observed when conventional breeding is used with the objective of improving the genetic makeup of bananas. Although spontaneous mutations in bananas are extremely rare, their incidence has been increased by the application of physical and/or chemical mutagenic agents (Al-Qurainy and Khan, 2009 ). Under these circumstances, an improvement programme for the choicest variety of banana, ‘Martaman’ (AAB), which is based on mutation induction techniques, may be a suitable alternative for addressing these challenges while allowing genetic variation and helping achieve desirable mutants with suitable agronomic traits such as short or dwarf plant stature, shorter crop duration, greater yield, better fruit quality, nondropping character of the ripe finger, resistance or tolerance to biotic factors, such as sigatoka leaf spot disease and fusarium wilt. Hence, mutation breeding appears to be a promising alternative for planning crop improvement programmes for these banana varieties. An innovative approach, the macropropagation technique, was used in this experiment, where the inactive buds on corms of ‘Martaman’ banana were irradiated, followed by activation and plantlet generation by macropropagation. The most crucial aspects of induced mutagenesis are determining the radiosensitivity of the explants (corms) that need to be altered, choosing an efficient mutagenic agent, and determining the LD50, as it varies depending on the genotype and mutagen (Kodym and Afza, 2003 ). Higher mortality rates or injury to tissue could result from increased concentrations. With the above background, the current investigation was carried out to determine the LD50 value by exposing decorticated corms to gamma irradiation ( 60 Co) and to analyse the effects of gamma irradiation on the growth traits of macropropagated corms. 2. Materials and methods 2.1 Experimental site, plant material and preparation of the corms The experiment was conducted at the ICAR-AICRP on Fruits and Fruit Crops Breeding and Multiplication Centre (RIDF-XXIII project) of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, for 2 successive years (2018–19 & 2019–20). Sord suckers that were 3–4 months old and had 2–3 narrow leaves were collected from healthy plantations. The technique for preparing the corms, as illustrated by Uma et al. ( 2008 ) and Sannigrahi and Debnath ( 2017 ), was followed for this experiment. The remnants (part of the pseudostem, roots) of the collected corms were carefully removed with the use of a sharp knife to ensure that the obtained corms were free of nematodes and other root-borne diseases and then trimmed to a uniform size. The corm’s apical meristem was removed (decapitated) by creating a small cavity (2 cm in depth and 2 cm in diameter) at the center, with 4 crosswise cuts (approximately 1–2 cm in depth) on the remaining portion of the corm. The corms were treated by dipping for 10‒15 minutes in a disinfecting solution containing carbendazim (50% WP @ 1 g/litre) and shade dried for 4‒5 hours. 2.2 Irradiation-treated corms The corms were exposed to different dosages of gamma irradiation ( 60 Co) with strengths of 10, 20, 30, 40, 50 and 60 Gy, with an effective rate of dosage of 04.348 KGy/Hr by a GC-5000 system (source cobalt 60) at the Regional Nuclear Agriculture Centre (RNARC) of BARC-BRNS at BCKV, Mohanpur, Nadia. For each dose (treatment), 30 corms were exposed to irradiation, which included 10 corms per replication. No irradiation was applied to 30 corms as a control. 2.3 Preparation of the growth media bed, planting of irradiated corms and their multiplication Growth media beds (7 nos.) of convenient size (2 m × 0.75 m) were prepared with saw dust and a cocopeat mixture (1:1) at a depth of 15–20 cm and drenched with Trichoderma viridae @ 1 g/litre 3–5 days prior to planting the corms on the media bed. The irradiated corms were then planted immediately in growth media beds at 20 cm × 25 cm spacing, and light irrigation was performed with a hand sprayer at regular intervals, but care was taken to avoid overwatering. To activate the irradiated lateral buds and induce primary shoots, 5 ml benzyl aminopurine (BAP) solution (@ 20 ppm) was applied at weekly intervals, followed by light watering of the growth media beds. Similarly, primary shoots were subjected to decapitation followed by BAP application to produce secondary shoots, and secondary shoots were used to produce tertiary shoots. 2.4 Data collection and statistical analysis The investigation was designed with three replications and seven treatments in a randomized block design (RBD). Nonirradiated corms were used as a control treatment for comparison. The survival percentage of the corm buds, time (in days) of induction for the primary, secondary and tertiary shoots and their growth characteristics, i.e. , the number, height and girth of the induced shoots, number of leaves, width and length of the leaves, etc., were recorded from the irradiated (T 2 : 10 Gy to T 7 : 60 Gy) and nonirradiated (control) corms [T 1 ]. The lethal dose (LD50) of the bananas was estimated through a linear regression equation. The data for the growth traits were statistically inferred following randomized block design (RBD) analysis of variance (ANOVA) (Gomez and Gomez, 1984 ). 3. Results and Discussion 3.1 Determination of the LD50 Determination of the LD50 is a prerequisite for mutagenesis. In the present study, the LD50 was calculated with respect to the percentage of surviving corm buds after irradiation treatment and the number of induced primary buds per corm. The various doses of gamma irradiation significantly affected the survival rate (%) of the irradiated corms (Table 1 ). Table 1 Effects of gamma irradiation on the survival rate (%) of macropropagated buds of Martaman banana (AAB) Treatment * Survival rate (%) of corms % reduction over control T 1 : 0 Gy (control) 96.25 -- T 2 : 10 Gy 89.00 -7.53 T 3 : 20 Gy 72.50 -24.68 T 4 : 30 Gy 60.25 -37.40 T 5 : 40 Gy 45.00 -53.24 T 6 : 50 Gy 27.75 -71.16 T 7 : 60 Gy 19.50 -79.74 SEm (±) 0.829 -- CD 0.05 2.584 -- T 1 : 0 Gy (control), T 2 : 10 Gy (gamma irradiation), T 3 : 20 Gy, T 4 : 30 Gy, T 5 : 40 Gy, T 6 : 50 Gy and T 7 : 60 Gy The survival rate gradually decreased with increasing gamma irradiation dose. The maximum (96.25%) survival rate was recorded in the untreated control [T 1 ], which gradually decreased to 89.00%, 72.50%, 60.25%, 45.00%, 27.75% and 19.50% due to irradiation doses of 10 Gy [T 2 ], 20 Gy [T 3 ], 30 Gy [T 4 ], 40 Gy [T 5 ], 50 Gy [T 6 ] and 60 Gy [T 7 ], respectively. The reduction in the survival rate over the control was estimated to be the maximum (79.74%) with 60 Gy [T 7 ] and the minimum (7.53%) with 10 Gy [T 2 ], whereas a 53.24% reduction in the survival percentage was recorded in the corms treated with 40 Gy [T 5 ]. To estimate the LD50 by plotting the percent survival rate (X) on a graph in connection with the different irradiation dosages (Y) via simple linear regression, it was clearly observed that both the anticipated and actual values were tallying with each other in most of the cases, with R 2 values (0.9925) near 1, indicating a significant correlation between the various doses of gamma irradiation and their corresponding percent survival rates. The negative value of the regression coefficient indicated that the percent survival rate of the corms and irradiation dose had an inverse association (Fig. 1 ). Based on these calculations, 37.71 Gy was estimated as the lethal dose (LD50), which led to 50% mortality of the irradiated corm buds. Mishra et al. ( 2007 ) and Abdulhafiz et al. ( 2018 ) reported that the lethal doses for shoot meristems of the banana cultivars Grand Naine (AAA) and Tanduk (AAB) were 35 Gy and 37 Gy, respectively. Hence, the results of the current investigation are in agreement with the range recommended by earlier findings. The number of induced buds per corm significantly differed among the corms exposed to various doses of gamma radiation (Tables 2 , 3 & 4 ). The maximum number of buds per corm was induced in the untreated control corms [T 1 ]. A simple linear regression revealed that the R 2 value was 0.9708, which indicates a significant correlation between the various gamma irradiation doses and their corresponding induced primary buds per corm (Fig. 2 ). According to this estimation, 38.95 Gy was the LD50 dose for the number of induced buds, which was almost 50% that of the untreated control. Sales et al. ( 2013 ) reported that an 80% decrease in the multiplication rate was caused by exposure to 40–60 Gy. Certain studies have concluded that the reduction rate in growth and survival is linked to direct injury to DNA molecules and that the cessation of the G2/M phase of somatic cell division is affected by radiation (Preussa and Britta, 2003 ). Postradiation damage to living systems is among the main causes of many forms of disruption in cell division and growth and frequently involves the breakage of DNA, especially double-strand breaks (DSBs) (Han and Yu, 2010 ; Oladosu et al., 2016 ). 3.2 Induction and growth of primary shoots The data concerning the induction and growth of primary shoots presented in Table 2 reported significant variations in the time taken for induction and the number of emerged primary shoots per corm, height and girth of primary shoots and leaf number and size (length and width). The maximum number of days (41.25 days) for bud break in the case of primary shoots was observed in the corms treated with 60 Gy [T 7 ], whereas among the irradiated corms, the minimum number of days for bud break was reported in the 10 Gy [T 2 ]-treated corms (28.50 days), which was statistically similar to the 20 Gy [T 3 ]-treated corms (29.00 days). The control (nonirradiated) corms [T 1 ] took 26.75 days for primary shoot induction. Table 2 Effects of gamma irradiation on the growth of primary shoots of macropropagated buds of ‘Martaman’ banana (AAB) - Time taken for induction, number, height and girth of induced primary shoot, number, length and breadth of leaf per primary shoot Treatment * Days taken for bud break Induced primary shoots/corm (no.) Height of primary shoot (cm) Girth of primary shoot (cm) Leaf/primary shoot (no.) Length of leaf (cm) Breadth of leaf (cm) T 1 : 0 Gy (control) 26.75 4.15 15.28 6.23 2.40 18.25 8.30 T 2 : 10 Gy 28.50 3.50 13.65 6.43 2.65 16.54 7.18 T 3 : 20 Gy 29.00 3.20 12.50 6.35 2.45 15.75 5.03 T 4 : 30 Gy 31.25 2.75 12.95 5.86 2.30 16.90 6.33 T 5 : 40 Gy 34.55 1.67 9.74 4.23 2.35 14.00 5.80 T 6 : 50 Gy 38.20 1.40 9.60 4.37 2.20 13.55 4.62 T 7 : 60 Gy 41.25 1.15 9.15 4.29 2.25 13.80 4.15 SEm (±) 0.497 0.026 0.143 0.084 0.033 0.148 0.095 CD 0.05 1.550 0.081 0.445 0.263 0.103 0.462 0.297 T 1 : 0 Gy (control), T 2 : 10 Gy (gamma irradiation), T 3 : 20 Gy, T 4 : 30 Gy, T 5 : 40 Gy, T 6 : 50 Gy and T 7 : 60 Gy Considerable phenotypic variation was observed among the primary shoots induced after mutagenic treatment. The irradiated corms treated with 10 Gy [T 2 ] and 20 Gy [T 3 ] responded positively to primary shoot induction and produced 3.50 shoots/corm and 3.20 shoots/corm, whereas at higher doses (40–60 Gy), the number of primary shoots induced per corm was less than 2.00 shoots/corm. The height and girth of the induced primary shoots varied significantly from 9.15 cm to 15.28 cm and from 4.29 cm to 6.43 cm, respectively, due to the different treatments. The minimum height (9.15 cm) and girth (4.23 cm) of the primary shoots were recorded in corms under 60 Gy [T 7 ]- and 40 Gy [T 5 ]-treated corms. The data depicted in Table 2 clearly show that the height and girth of the shoots did not significantly differ among the control [T 1 ] (15.28 cm and 6.23 cm), 10 Gy [T 2 ] (13.65 cm and 6.43 cm) and 20 Gy [T 3 ] (12.50 cm and 6.35 cm) treatments. However, a significant difference between the control [T 1 ] and 40 Gy-treated corms [T 5 ] was observed in terms of the height and girth of the shoots. The maximum leaf number (2.65) was recorded in the 10 Gy-treated corms [T 2 ], which was statistically similar to that in the 20 Gy-treated corms [T 3 ] (2.45), whereas in the 40 Gy-treated corms [T 5 ], it was 2.35. The maximum length (18.25 cm) and width (8.30 cm) width (13.55 and 4.15 cm) of the primary shoot of the control plants [T1] were recorded for the leaves, whereas the minimum values (13.55 and 4.15 cm) were recorded for the 50 Gy [T6]- and 60 Gy [T7]-treated corms, respectively. The present results are analogous to those of Abdulhafiz et al. ( 2018 ), who reported a decrease in shoot multiplication and shoot growth after a 30 Gy dose of gamma radiation, whereas Karmakar et al . (2001) reported that the growth of explants decreased in proportion to an increase in the gamma-ray dose. 3.3 Induction and growth of secondary shoots The observations obtained regarding the induction and growth of secondary shoots, with respect to the number, girth and height of secondary shoots and the number, width and length of leaves per secondary shoot, significantly varied with irradiation treatment at different doses (Table 3 ). Table 3 Effects of gamma irradiation on the growth of secondary shoots of macropropagated buds of ‘Martaman’ banana (AAB) - Time taken for induction, number, height and girth of induced secondary shoot, number, length and breadth of leaf per secondary shoot Treatment * Days taken for bud break Induced secondary shoots/primary shoot (no.) Height of secondary shoot (cm) Girth of secondary shoot (cm) Leaf/ secondary shoot (no.) Length of leaf (cm) Breadth of leaf (cm) T 1 : 0 Gy 28.50 2.90 13.98 5.03 2.50 14.78 5.33 T 2 : 10 Gy 30.00 2.65 12.44 5.43 2.53 13.25 4.60 T 3 : 20 Gy 30.75 2.40 11.93 5.45 2.78 14.50 5.13 T 4 : 30 Gy 32.00 1.80 10.25 4.60 2.20 14.43 5.18 T 5 : 40 Gy 36.50 1.25 9.08 3.90 2.48 12.00 4.03 T 6 : 50 Gy 40.25 1.20 8.75 4.15 2.15 11.63 3.75 T 7 : 60 Gy 42.00 1.15 8.43 3.80 2.10 11.25 3.53 SEm (±) 0.462 0.024 0.104 0.051 0.036 0.185 0.072 CD 0.05 1.440 0.073 0.323 0.158 0.112 0.578 0.223 T 1 : 0 Gy (control), T 2 : 10 Gy (gamma irradiation), T 3 : 20 Gy, T 4 : 30 Gy, T 5 : 40 Gy, T 6 : 50 Gy and T 7 : 60 Gy Corms treated with higher doses (T 5 , T 6 and T 7 ) (40 Gy, 50 Gy and 60 Gy) of irradiation took more days for bud breaking (36.50 days, 40.25 days and 42.00 days, respectively), and the number of secondary shoots induced per primary shoot was much lower (1.15–1.25) due to irradiation at 40–60 Gy [T 5 --T 7 ] than at 1.80–2.65 shoots per primary shoot for the irradiation treatments at 10–30 Gy [T 2 --T 4 ], whereas in nonirradiated control plants [T 1 ], the number of secondary shoots induced per primary shoot reached a maximum (2.90). The data depicted in Table 3 indicate that, beyond 40 Gy, the height (8.43–9.08 cm) and girth (3.80–4.15 cm) of the secondary shoots were lower than those in the other treatments, whereas at lower doses (10–30 Gy [T 2 --T 4 ]), the height and girth of the secondary shoots ranged from 10.25–12.44 cm and from 4.60–5.43 cm, respectively. The leaf number per secondary shoot varied significantly from 2.10 to 2.78 due to the irradiation treatments. The nonirradiated [T 1 ] corms (control) recorded the maximum length (14.78 cm) and breadth (5.33 cm) of the leaf, followed by the corms treated with gamma radiation doses of 20 Gy [T 3 ] (14.50 cm) and 30 Gy [T 4 ] (5.18 cm), whereas the corms treated with a 60 Gy dose [T 7 ] of gamma radiation recorded the minimum length (11.25 cm) and breadth (3.53 cm) of the leaf. 3.4 Induction and growth of tertiary shoots The data recorded on tertiary shoot induction and growth are presented in Table 4 , which reveals significant variations in the induction time and number of induced tertiary shoots from secondary shoots; the height and girth of tertiary shoots; and the number, length and width of leaves per tertiary shoot. The minimum time (29.00 days) for tertiary shoot induction in the untreated control corms [T 1 ] increased to 31.50 to 43.75 days because of the irradiation treatment at different doses (10–60 Gy). The number of induced tertiary shoots per secondary shoot was lower (1.20–1.45) due to irradiation at higher doses [T 5 --T 7 ] (40–60 Gy), whereas irradiation at lower doses [T 2 --T 4 ] (10–30 Gy) induced a greater number of tertiary shoots per secondary shoot, ranging from 1.95–2.90 tertiary shoots per secondary shoot. The untreated control plants [T 1 ] produced the maximum number of tertiary shoots per secondary shoot (3.15). Table 4 Effects of gamma irradiation on the growth of tertiary shoots of macropropagated buds of Martaman banana (AAB) - Time taken for induction; number, height and girth of induced tertiary shoots; number, length and breadth of leaves per tertiary shoot Treatment Days taken for bud break Tertiary shoots/secondary shoot (no.) Height of tertiary shoot (cm) Girth of tertiary shoot (cm) Leaf/ tertiary shoot (no.) Length of leaf (cm) Breadth of leaf (cm) T 1 : 0 Gy 29.00 3.15 8.20 3.49 2.43 7.55 3.68 T 2 : 10 Gy 31.50 2.90 7.89 3.18 2.35 7.10 3.50 T 3 : 20 Gy 32.25 2.70 7.23 3.05 2.32 7.28 3.35 T 4 : 30 Gy 34.50 1.95 6.70 2.90 2.23 6.83 3.31 T 5 : 40 Gy 37.50 1.45 6.18 2.80 2.18 6.50 2.98 T 6 : 50 Gy 42.50 1.35 5.83 1.95 2.13 6.18 2.65 T 7 : 60 Gy 43.75 1.20 5.35 1.88 2.05 6.10 2.73 SEm (±) 0.477 0.031 0.094 0.031 0.022 0.105 0.044 CD 0.05 1.486 0.097 0.292 0.097 0.069 0.328 0.137 T 1 : 0 Gy (control), T 2 : 10 Gy (gamma irradiation), T 3 : 20 Gy, T 4 : 30 Gy, T 5 : 40 Gy, T 6 : 50 Gy and T 7 : 60 Gy The data presented in Table 4 clearly show that the height and girth of the shoots significantly differed between the control (8.20 cm and 3.49 cm, respectively) and 10 Gy [T 2 ]-treated corms (7.89 cm and 3.18 cm, respectively), followed by the 20 Gy [T 3 ]-treated corms (7.23 cm and 3.05 cm, respectively). The number of leaves produced per tertiary shoot decreased with increasing irradiation dose. The maximum leaf number (2.43) was recorded for nontreated control corms [T 1 ], followed by 10 Gy [T 2 ] and 20 Gy [T 3 ] (2.35 and 2.32, respectively), whereas the minimum leaf number (2.05) was recorded for 60 Gy-treated corms [T 7 ]. The maximum length (7.28 cm) and width (3.50 cm) of the tertiary shoot produced per secondary shoot from 20 Gy [T 3 ]- and 10 Gy [T 2 ]-treated corms were recorded for the leaves among the irradiated corms, whereas the minimum length (7.28 cm) and width (3.50 cm) were recorded for the corms treated with 60 Gy [T 7 ] and 50 Gy [T 6 ] doses of irradiation (6.10 and 2.65 cm, respectively). These results are in line with the previous work of Karmakar et al . (2001), who reported a general decrease in leaf growth with a linear increase in the irradiation dose of gamma rays compared with plantlets with no irradiation treatment. 4. Conclusion In the present study, gamma irradiation significantly affected the growth of macropropagated buds of ‘Martaman’ banana (AAB). According to these studies, the growth characteristics decreased in proportion to the increase in gamma-ray exposure. The lethal dose (LD50) for the irradiated corms of banana cv. ‘Martaman’ on the basis of the 50% survival rate and induction of primary buds per corm were 37.71 Gy and 38.95 Gy, respectively. Therefore, 20 Gy and 30 Gy could be used to induce morphological variation among the population of banana cv. ‘Martaman’ multiplied by the macropropagation technique. The results of the present study will provide useful hints for designing mutation breeding programs for improving banana varieties. Declarations Author authorship contribution statement Tanushree Saha, Soustav Datta, Rahi Masum Reja, Shivaji Chattopadhyay, Sanjit Debnath, Sarthak Bhattacharya: Conceptualization, Investigation, Methodology, Validation, Visualization, Writing – original draft. Tanushree Saha, Sanjit Debnath, Abdulrahman Alasmari, Lamya Ahmed Alkeridis, Laila A. Al-Shuraym, Ahmed Gaber, Akbar Hossain: Formal analysis, Data curation, Project administration, Supervision, Review and Editing. All authors reviewed the findings and accepted the final version of the manuscript. Funding: This work was executed at Bidhan Chandra Krishi Viswavidyalaya (BCKV) with financial assistance from the DST-INSPIRE Fellowship, the ICAR-All India Coordinated Research Project (AICRP) on Fruits, and other ad hoc projects, state plan projects and the RIDF-XXIII project. The study also received a partial financial support from Princess Nourah bint Abdulrahman University Researchers Supporting Project (PNURSP2025R82), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia. Acknowledgement The authors extend their appreciation to Bidhan Chandra Krishi Viswavidyalaya (BCKV) for financial assistance from the DST-INSPIRE Fellowship, the ICAR-All India Coordinated Research Project (AICRP) on Fruits, and other ad hoc projects under investigation, such as Dr. Sanjit Debnath (P.I.), the state plan project and the RIDF-XXIII project. The authors would like to express their gratitude to the collaborative organization (BCKV) for granting the necessary research facilities as well as all the sources of financial assistance. The authors wish to thank Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2025R82), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia, for partially supporting this study. Ethics declaration Not applicable. Conflicts of interest The authors declare that they have no competing financial interests. Data availability statements The datasets generated during and/or analysed during the current study will be available from the corresponding author upon request. References Abdulhafiz, F., Kayat, F. and Zakaria, S. (2018). Gamma irradiation effect on the growth of Musa cv. Tanduk (AAB). Asian Journal of Agriculture and Biology , 6 (2):135-142. Al-Qurainy, F. and Khan, S. (2009). Mutagenic effects of sodium azide and its application in crop improvement. World Applied Sciences Journal , 6 (12):1589-1601. Indian Horticulture Database (2020). Area and Production of Horticulture Crops - All India: 2019-20. Indian Horticulture Database 2019-20 , NHB, MoA, GoI, Gurgaon, Haryana, pp. 1. Gomez, K. A. and Gomez, A. A. (1984). Statistical Procedures for Agricultural Research, John Wiley & Sons. Inc. New York. Han, W. and Yu, K. N. (2010). Ionizing radiation, DNA double strand break and mutation. Advances in Genetics Research , 4 :197-210. Karmarkar, V. M., Kulkarni, V. M., Suprasanna, P., Bapat, V. A. and Rao, P. S. (2001). Radiosensitivity of in vivo and in vitro cultures of banana cv. Basrai (AAA). Fruits , 56 (2):67-74. Kodym, A. and Afza, R. (2003). Physical and chemical mutagenesis. In: Plant functional genomics: methods and protocols, Methods in molecular biology , (Ed. Grotewold E; Human Press Inc., Totowa, NJ), pp. 189-203. Kumar, N. (2006). Problems and prospects of banana breeding in India. Journal of Horticultural Sciences , 1 (2):77-94. Mishra, P. J., Ganapathi, T. R., Suprasanna, P. and Bapat, V. A. (2007). Effect of single and recurrent gamma irradiation on in vitro shoot cultures of banana. International Journal of Fruit Science , 7 (1):47-57. Oladosu, Y., Rafii, M.Y., Abdullah, N., Hussin, G., Ramli, A., Rahim, H.A., Miah, G. and Usman, M. (2016). Principle and application of plant mutagenesis in crop improvement: a review. Biotechnology and Biotechnological Equipment , 30 (1):1-16. Preussa, S. B. and Britta, A. B. (2003). A DNA-damage-induced cell cycle checkpoint in Arabidopsis. Genetics , 164 :323-334. Sales, E., Lopez, J., Espino, R., Butardo, N. and Gonzalez, L. (2013). Improvement of bananas through gamma ray irradiation. Philippine Journal of Crop Science , 38 (2):47-53. Sannigrahi, S. and Debnath, S. (2017). Studies on shoot and root induction of eight commercial banana varieties of West Bengal by macropropagation technique. International Journal of Current Research , 9 (6):52426-52429. Uma, S., Saraswathi, M. S., Durai, P. and Mahalakshmi, B. (2008). Propagating banana a farmer friendly technology. Indian Horticulture , 53 (5):11-12. 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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-7207984","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":492087317,"identity":"d819e347-ee5d-41fa-be81-00025bf997d5","order_by":0,"name":"Tanushree Saha","email":"","orcid":"","institution":"Assistant Director of Horticulture, Department of Food Processing Indusctries and Horticulture, Govt. of West Bengal, India","correspondingAuthor":false,"prefix":"","firstName":"Tanushree","middleName":"","lastName":"Saha","suffix":""},{"id":492087318,"identity":"04f29d31-a236-4583-af3d-d2633a5841bd","order_by":1,"name":"Soustav Datta","email":"","orcid":"","institution":"The Agricultural Infrastracture Fund, NABCONS (A Wholly Subsidy Body of NABARD), West Bengal, India)","correspondingAuthor":false,"prefix":"","firstName":"Soustav","middleName":"","lastName":"Datta","suffix":""},{"id":492087319,"identity":"65f0cb4e-0818-4e5b-81a6-2e4642708d40","order_by":2,"name":"Rahi Masum Reja","email":"","orcid":"","institution":"BCKV: Bidhan Chandra Krishi Viswa Vidyalaya","correspondingAuthor":false,"prefix":"","firstName":"Rahi","middleName":"Masum","lastName":"Reja","suffix":""},{"id":492087320,"identity":"22afcb1b-6771-4420-b4a5-88343cd17412","order_by":3,"name":"Shivaji Chattopadhyay","email":"","orcid":"","institution":"BCKV: Bidhan Chandra Krishi Viswa Vidyalaya","correspondingAuthor":false,"prefix":"","firstName":"Shivaji","middleName":"","lastName":"Chattopadhyay","suffix":""},{"id":492087321,"identity":"fc97aa97-9cf5-494e-bd63-af2f040f93ea","order_by":4,"name":"Sanjit Debnath","email":"","orcid":"","institution":"BCKV: Bidhan Chandra Krishi Viswa Vidyalaya","correspondingAuthor":false,"prefix":"","firstName":"Sanjit","middleName":"","lastName":"Debnath","suffix":""},{"id":492087322,"identity":"29d5d3a8-af3b-484f-ba9a-cf081cc4b759","order_by":5,"name":"Sarthak Bhattacharya","email":"","orcid":"","institution":"The Neotia University","correspondingAuthor":false,"prefix":"","firstName":"Sarthak","middleName":"","lastName":"Bhattacharya","suffix":""},{"id":492087323,"identity":"057bf542-bd52-40bb-b1c8-d21c56b25100","order_by":6,"name":"Abdulrahman Alasmari","email":"","orcid":"","institution":"University of Tabuk","correspondingAuthor":false,"prefix":"","firstName":"Abdulrahman","middleName":"","lastName":"Alasmari","suffix":""},{"id":492087324,"identity":"7a07ddf7-aec5-4d83-9e77-36277ccd4885","order_by":7,"name":"Lamya Ahmed Alkeridis","email":"","orcid":"","institution":"Princess Noura Bint AbdulRahman University: Princess Nourah bint Abdulrahman University","correspondingAuthor":false,"prefix":"","firstName":"Lamya","middleName":"Ahmed","lastName":"Alkeridis","suffix":""},{"id":492087325,"identity":"542dba12-834a-45b0-8335-5c9cc0e1851f","order_by":8,"name":"Laila A. Al-Shuraym","email":"","orcid":"","institution":"Princess Noura Bint AbdulRahman University: Princess Nourah bint Abdulrahman University","correspondingAuthor":false,"prefix":"","firstName":"Laila","middleName":"A.","lastName":"Al-Shuraym","suffix":""},{"id":492087326,"identity":"7bb78496-333e-4055-9bd1-671f8d921a43","order_by":9,"name":"Ahmed Gaber","email":"","orcid":"","institution":"Taif University","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Gaber","suffix":""},{"id":492087327,"identity":"d66888a5-098a-43e3-a5fa-ad9aa430c954","order_by":10,"name":"Akbar Hossain","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYDACHh4GBsYGEAtCyoGIAw9I0WIM1pJAnBYISASz8Wnh7zl78HPlDht7+fbDbY9599ilzw87/BBoi52cbgN2LRJn+5Ilz55JS9xwJrHdmOdZcu7G22kGQC3JxmYHcFhznsdAsrHtcIIBQ2KbdM6BA7kbZyeAtBxI3IZDi/x5HuOfQC328v0PwVrSDWenf8CrxeBsjxnIFsaGGxBbEuSlc/DbYnjmXJplYxvQLzeAtvw5kGy4QTqn4ECCAW6/yJ3JPXyzsQ0YYv3pzyRnHLCTl5+dvvnDhwo7OZzex3QqWKUBscpBQL6BFNWjYBSMglEwEgAAwQ9nvrzSFa4AAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-0264-2712","institution":"Bangladesh Wheat and Maize Research Institute","correspondingAuthor":true,"prefix":"","firstName":"Akbar","middleName":"","lastName":"Hossain","suffix":""}],"badges":[],"createdAt":"2025-07-24 17:55:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7207984/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7207984/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87903069,"identity":"01461ba4-29dc-4001-b36f-e1cfc12aa345","added_by":"auto","created_at":"2025-07-30 08:27:48","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":32024,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of gamma irradiation dose on the survival rate (%) of corms of banana cv. ‘Martaman’. T\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control), T\u003csub\u003e2\u003c/sub\u003e: 10 Gy (gamma irradiation), T\u003csub\u003e3\u003c/sub\u003e: 20 Gy, T\u003csub\u003e4\u003c/sub\u003e: 30 Gy, T\u003csub\u003e5\u003c/sub\u003e: 40 Gy, T\u003csub\u003e6\u003c/sub\u003e: 50 Gy and T\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7207984/v1/cdc86a43a650ecd01ec418a1.png"},{"id":87903552,"identity":"36c5ebd3-a4ba-4e3c-84b8-8fe1ef11307e","added_by":"auto","created_at":"2025-07-30 08:35:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":30850,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of gamma irradiation dose on the number of induced primary buds per corm. T\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control), T\u003csub\u003e2\u003c/sub\u003e: 10 Gy (gamma irradiation), T\u003csub\u003e3\u003c/sub\u003e: 20 Gy, T\u003csub\u003e4\u003c/sub\u003e: 30 Gy, T\u003csub\u003e5\u003c/sub\u003e: 40 Gy, T\u003csub\u003e6\u003c/sub\u003e: 50 Gy and T\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7207984/v1/646f6b1950dab0e74febbc1b.png"},{"id":91419028,"identity":"26623780-eba5-4974-967f-6dae32d13e91","added_by":"auto","created_at":"2025-09-16 09:53:49","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1172320,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7207984/v1/fde8bfa9-f334-435e-b3c8-57b63a59f52d.pdf"}],"financialInterests":"","formattedTitle":"Studies on the radiosensitivity of macropropagated corm buds of banana for the improvement of commercial triploid banana cultivars","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eBananas are among the major fruit crops for subsistence of farmers, ensuring year-round security of food and income, especially in tropical and subtropical regions. India is the largest producer of bananas, producing 31504 thousand MT from an area of 878 thousand hectares (Indian Horticulture Database, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In West Bengal, bananas are among the most significant commercial fruit crops, and the variety \u0026lsquo;Martaman\u0026rsquo; (Musa AAB) is the most important commercial variety contributing approximately 1/3rd of the total banana production in the state, and it has high market demand and price. However, commercial cultivation of this variety is remarkably impeded by several biotic and abiotic stresses, including a lack of clean and high-quality planting material, crop loss due to infestations caused by diseases (\u003cem\u003eviz.\u003c/em\u003e, fusarium wilt, sigatoka leaf spot), cyclone damage resulting in tall heights, falling fingers from ripe hands and bunches and a short shelf life.\u003c/p\u003e\u003cp\u003eGiven their parthenocarpic, sterile and polyploid properties, conventional breeding or sexual hybridization might have little potential for improving banana production (Uma \u003cem\u003eet al\u003c/em\u003e., 2016). This is a major limitation for the improvement of commercial triploids such as cvs. \u0026lsquo;Rasthali\u0026rsquo; (Silk, AAB) and \u0026lsquo;Robusta\u0026rsquo; (AAA) (Kumar, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). The benefit of mutation-based breeding in asexually propagated crops is that it has the potential to alter one or two characteristics without impacting the fundamental genetic background, which is frequently observed when conventional breeding is used with the objective of improving the genetic makeup of bananas. Although spontaneous mutations in bananas are extremely rare, their incidence has been increased by the application of physical and/or chemical mutagenic agents (Al-Qurainy and Khan, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eUnder these circumstances, an improvement programme for the choicest variety of banana, \u0026lsquo;Martaman\u0026rsquo; (AAB), which is based on mutation induction techniques, may be a suitable alternative for addressing these challenges while allowing genetic variation and helping achieve desirable mutants with suitable agronomic traits such as short or dwarf plant stature, shorter crop duration, greater yield, better fruit quality, nondropping character of the ripe finger, resistance or tolerance to biotic factors, such as sigatoka leaf spot disease and fusarium wilt. Hence, mutation breeding appears to be a promising alternative for planning crop improvement programmes for these banana varieties.\u003c/p\u003e\u003cp\u003eAn innovative approach, the macropropagation technique, was used in this experiment, where the inactive buds on corms of \u0026lsquo;Martaman\u0026rsquo; banana were irradiated, followed by activation and plantlet generation by macropropagation. The most crucial aspects of induced mutagenesis are determining the radiosensitivity of the explants (corms) that need to be altered, choosing an efficient mutagenic agent, and determining the LD50, as it varies depending on the genotype and mutagen (Kodym and Afza, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Higher mortality rates or injury to tissue could result from increased concentrations. With the above background, the current investigation was carried out to determine the LD50 value by exposing decorticated corms to gamma irradiation (\u003csup\u003e60\u003c/sup\u003eCo) and to analyse the effects of gamma irradiation on the growth traits of macropropagated corms.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Experimental site, plant material and preparation of the corms\u003c/h2\u003e\u003cp\u003eThe experiment was conducted at the ICAR-AICRP on Fruits and Fruit Crops Breeding and Multiplication Centre (RIDF-XXIII project) of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, for 2 successive years (2018\u0026ndash;19 \u0026amp; 2019\u0026ndash;20). Sord suckers that were 3\u0026ndash;4 months old and had 2\u0026ndash;3 narrow leaves were collected from healthy plantations. The technique for preparing the corms, as illustrated by Uma et al. (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) and Sannigrahi and Debnath (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), was followed for this experiment. The remnants (part of the pseudostem, roots) of the collected corms were carefully removed with the use of a sharp knife to ensure that the obtained corms were free of nematodes and other root-borne diseases and then trimmed to a uniform size. The corm\u0026rsquo;s apical meristem was removed (decapitated) by creating a small cavity (2 cm in depth and 2 cm in diameter) at the center, with 4 crosswise cuts (approximately 1\u0026ndash;2 cm in depth) on the remaining portion of the corm. The corms were treated by dipping for 10‒15 minutes in a disinfecting solution containing carbendazim (50% WP @ 1 g/litre) and shade dried for 4‒5 hours.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Irradiation-treated corms\u003c/h2\u003e\u003cp\u003eThe corms were exposed to different dosages of gamma irradiation (\u003csup\u003e60\u003c/sup\u003eCo) with strengths of 10, 20, 30, 40, 50 and 60 Gy, with an effective rate of dosage of 04.348 KGy/Hr by a GC-5000 system (source cobalt 60) at the Regional Nuclear Agriculture Centre (RNARC) of BARC-BRNS at BCKV, Mohanpur, Nadia. For each dose (treatment), 30 corms were exposed to irradiation, which included 10 corms per replication. No irradiation was applied to 30 corms as a control.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Preparation of the growth media bed, planting of irradiated corms and their multiplication\u003c/h2\u003e\u003cp\u003eGrowth media beds (7 nos.) of convenient size (2 m \u0026times; 0.75 m) were prepared with saw dust and a cocopeat mixture (1:1) at a depth of 15\u0026ndash;20 cm and drenched with \u003cem\u003eTrichoderma viridae\u003c/em\u003e @ 1 g/litre 3\u0026ndash;5 days prior to planting the corms on the media bed. The irradiated corms were then planted immediately in growth media beds at 20 cm \u0026times; 25 cm spacing, and light irrigation was performed with a hand sprayer at regular intervals, but care was taken to avoid overwatering. To activate the irradiated lateral buds and induce primary shoots, 5 ml benzyl aminopurine (BAP) solution (@ 20 ppm) was applied at weekly intervals, followed by light watering of the growth media beds. Similarly, primary shoots were subjected to decapitation followed by BAP application to produce secondary shoots, and secondary shoots were used to produce tertiary shoots.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Data collection and statistical analysis\u003c/h2\u003e\u003cp\u003eThe investigation was designed with three replications and seven treatments in a randomized block design (RBD). Nonirradiated corms were used as a control treatment for comparison. The survival percentage of the corm buds, time (in days) of induction for the primary, secondary and tertiary shoots and their growth characteristics, \u003cem\u003ei.e.\u003c/em\u003e, the number, height and girth of the induced shoots, number of leaves, width and length of the leaves, etc., were recorded from the irradiated (T\u003csub\u003e2\u003c/sub\u003e: 10 Gy to T\u003csub\u003e7\u003c/sub\u003e: 60 Gy) and nonirradiated (control) corms [T\u003csub\u003e1\u003c/sub\u003e]. The lethal dose (LD50) of the bananas was estimated through a linear regression equation. The data for the growth traits were statistically inferred following randomized block design (RBD) analysis of variance (ANOVA) (Gomez and Gomez, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1984\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Determination of the LD50\u003c/h2\u003e\u003cp\u003eDetermination of the LD50 is a prerequisite for mutagenesis. In the present study, the LD50 was calculated with respect to the percentage of surviving corm buds after irradiation treatment and the number of induced primary buds per corm. The various doses of gamma irradiation significantly affected the survival rate (%) of the irradiated corms (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffects of gamma irradiation on the survival rate (%) of macropropagated buds of Martaman banana (AAB)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTreatment\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSurvival rate (%) of corms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e% reduction over control\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e96.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e--\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e2\u003c/sub\u003e: 10 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e89.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-7.53\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e3\u003c/sub\u003e: 20 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e72.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-24.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e4\u003c/sub\u003e: 30 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e60.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-37.40\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e5\u003c/sub\u003e: 40 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e45.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-53.24\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e6\u003c/sub\u003e: 50 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e27.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-71.16\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e19.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-79.74\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSEm (\u0026plusmn;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.829\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e--\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCD\u003csub\u003e0.05\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.584\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e--\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control), T\u003csub\u003e2\u003c/sub\u003e: 10 Gy (gamma irradiation), T\u003csub\u003e3\u003c/sub\u003e: 20 Gy, T\u003csub\u003e4\u003c/sub\u003e: 30 Gy, T\u003csub\u003e5\u003c/sub\u003e: 40 Gy, T\u003csub\u003e6\u003c/sub\u003e: 50 Gy and T\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe survival rate gradually decreased with increasing gamma irradiation dose. The maximum (96.25%) survival rate was recorded in the untreated control [T\u003csub\u003e1\u003c/sub\u003e], which gradually decreased to 89.00%, 72.50%, 60.25%, 45.00%, 27.75% and 19.50% due to irradiation doses of 10 Gy [T\u003csub\u003e2\u003c/sub\u003e], 20 Gy [T\u003csub\u003e3\u003c/sub\u003e], 30 Gy [T\u003csub\u003e4\u003c/sub\u003e], 40 Gy [T\u003csub\u003e5\u003c/sub\u003e], 50 Gy [T\u003csub\u003e6\u003c/sub\u003e] and 60 Gy [T\u003csub\u003e7\u003c/sub\u003e], respectively. The reduction in the survival rate over the control was estimated to be the maximum (79.74%) with 60 Gy [T\u003csub\u003e7\u003c/sub\u003e] and the minimum (7.53%) with 10 Gy [T\u003csub\u003e2\u003c/sub\u003e], whereas a 53.24% reduction in the survival percentage was recorded in the corms treated with 40 Gy [T\u003csub\u003e5\u003c/sub\u003e].\u003c/p\u003e\u003cp\u003eTo estimate the LD50 by plotting the percent survival rate (X) on a graph in connection with the different irradiation dosages (Y) via simple linear regression, it was clearly observed that both the anticipated and actual values were tallying with each other in most of the cases, with R\u003csup\u003e2\u003c/sup\u003e values (0.9925) near 1, indicating a significant correlation between the various doses of gamma irradiation and their corresponding percent survival rates. The negative value of the regression coefficient indicated that the percent survival rate of the corms and irradiation dose had an inverse association (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Based on these calculations, 37.71 Gy was estimated as the lethal dose (LD50), which led to 50% mortality of the irradiated corm buds. Mishra et al. (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) and Abdulhafiz et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) reported that the lethal doses for shoot meristems of the banana cultivars Grand Naine (AAA) and Tanduk (AAB) were 35 Gy and 37 Gy, respectively. Hence, the results of the current investigation are in agreement with the range recommended by earlier findings.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe number of induced buds per corm significantly differed among the corms exposed to various doses of gamma radiation (Tables\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u0026amp; \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The maximum number of buds per corm was induced in the untreated control corms [T\u003csub\u003e1\u003c/sub\u003e].\u003c/p\u003e\u003cp\u003eA simple linear regression revealed that the R\u003csup\u003e2\u003c/sup\u003e value was 0.9708, which indicates a significant correlation between the various gamma irradiation doses and their corresponding induced primary buds per corm (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). According to this estimation, 38.95 Gy was the LD50 dose for the number of induced buds, which was almost 50% that of the untreated control.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSales et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) reported that an 80% decrease in the multiplication rate was caused by exposure to 40\u0026ndash;60 Gy. Certain studies have concluded that the reduction rate in growth and survival is linked to direct injury to DNA molecules and that the cessation of the G2/M phase of somatic cell division is affected by radiation (Preussa and Britta, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Postradiation damage to living systems is among the main causes of many forms of disruption in cell division and growth and frequently involves the breakage of DNA, especially double-strand breaks (DSBs) (Han and Yu, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Oladosu et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Induction and growth of primary shoots\u003c/h2\u003e\u003cp\u003eThe data concerning the induction and growth of primary shoots presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e reported significant variations in the time taken for induction and the number of emerged primary shoots per corm, height and girth of primary shoots and leaf number and size (length and width). The maximum number of days (41.25 days) for bud break in the case of primary shoots was observed in the corms treated with 60 Gy [T\u003csub\u003e7\u003c/sub\u003e], whereas among the irradiated corms, the minimum number of days for bud break was reported in the 10 Gy [T\u003csub\u003e2\u003c/sub\u003e]-treated corms (28.50 days), which was statistically similar to the 20 Gy [T\u003csub\u003e3\u003c/sub\u003e]-treated corms (29.00 days). The control (nonirradiated) corms [T\u003csub\u003e1\u003c/sub\u003e] took 26.75 days for primary shoot induction.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffects of gamma irradiation on the growth of primary shoots of macropropagated buds of \u0026lsquo;Martaman\u0026rsquo; banana (AAB) - Time taken for induction, number, height and girth of induced primary shoot, number, length and breadth of leaf per primary shoot\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTreatment\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDays taken for bud break\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInduced primary shoots/corm (no.)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHeight of primary shoot\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGirth of primary shoot\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLeaf/primary shoot (no.)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eLength of leaf (cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eBreadth of leaf (cm)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e26.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e15.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e6.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e18.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e8.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e2\u003c/sub\u003e: 10 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e28.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e13.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e6.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e16.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e7.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e3\u003c/sub\u003e: 20 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e29.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e6.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e15.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e5.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e4\u003c/sub\u003e: 30 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e31.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e16.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e6.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e5\u003c/sub\u003e: 40 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e34.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9.74\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e4.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e14.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e5.80\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e6\u003c/sub\u003e: 50 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e38.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e4.37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e13.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e4.62\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e41.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e4.29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e13.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e4.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSEm (\u0026plusmn;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.497\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.026\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.143\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.084\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.033\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.148\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.095\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCD\u003csub\u003e0.05\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.550\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.081\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.445\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.263\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.103\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.462\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.297\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control), T\u003csub\u003e2\u003c/sub\u003e: 10 Gy (gamma irradiation), T\u003csub\u003e3\u003c/sub\u003e: 20 Gy, T\u003csub\u003e4\u003c/sub\u003e: 30 Gy, T\u003csub\u003e5\u003c/sub\u003e: 40 Gy, T\u003csub\u003e6\u003c/sub\u003e: 50 Gy and T\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eConsiderable phenotypic variation was observed among the primary shoots induced after mutagenic treatment. The irradiated corms treated with 10 Gy [T\u003csub\u003e2\u003c/sub\u003e] and 20 Gy [T\u003csub\u003e3\u003c/sub\u003e] responded positively to primary shoot induction and produced 3.50 shoots/corm and 3.20 shoots/corm, whereas at higher doses (40\u0026ndash;60 Gy), the number of primary shoots induced per corm was less than 2.00 shoots/corm. The height and girth of the induced primary shoots varied significantly from 9.15 cm to 15.28 cm and from 4.29 cm to 6.43 cm, respectively, due to the different treatments. The minimum height (9.15 cm) and girth (4.23 cm) of the primary shoots were recorded in corms under 60 Gy [T\u003csub\u003e7\u003c/sub\u003e]- and 40 Gy [T\u003csub\u003e5\u003c/sub\u003e]-treated corms. The data depicted in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e clearly show that the height and girth of the shoots did not significantly differ among the control [T\u003csub\u003e1\u003c/sub\u003e] (15.28 cm and 6.23 cm), 10 Gy [T\u003csub\u003e2\u003c/sub\u003e] (13.65 cm and 6.43 cm) and 20 Gy [T\u003csub\u003e3\u003c/sub\u003e] (12.50 cm and 6.35 cm) treatments. However, a significant difference between the control [T\u003csub\u003e1\u003c/sub\u003e] and 40 Gy-treated corms [T\u003csub\u003e5\u003c/sub\u003e] was observed in terms of the height and girth of the shoots. The maximum leaf number (2.65) was recorded in the 10 Gy-treated corms [T\u003csub\u003e2\u003c/sub\u003e], which was statistically similar to that in the 20 Gy-treated corms [T\u003csub\u003e3\u003c/sub\u003e] (2.45), whereas in the 40 Gy-treated corms [T\u003csub\u003e5\u003c/sub\u003e], it was 2.35. The maximum length (18.25 cm) and width (8.30 cm) width (13.55 and 4.15 cm) of the primary shoot of the control plants [T1] were recorded for the leaves, whereas the minimum values (13.55 and 4.15 cm) were recorded for the 50 Gy [T6]- and 60 Gy [T7]-treated corms, respectively. The present results are analogous to those of Abdulhafiz et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), who reported a decrease in shoot multiplication and shoot growth after a 30 Gy dose of gamma radiation, whereas Karmakar \u003cem\u003eet al\u003c/em\u003e. (2001) reported that the growth of explants decreased in proportion to an increase in the gamma-ray dose.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Induction and growth of secondary shoots\u003c/h2\u003e\u003cp\u003eThe observations obtained regarding the induction and growth of secondary shoots, with respect to the number, girth and height of secondary shoots and the number, width and length of leaves per secondary shoot, significantly varied with irradiation treatment at different doses (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffects of gamma irradiation on the growth of secondary shoots of macropropagated buds of \u0026lsquo;Martaman\u0026rsquo; banana (AAB) - Time taken for induction, number, height and girth of induced secondary shoot, number, length and breadth of leaf per secondary shoot\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTreatment\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDays taken for bud break\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInduced secondary shoots/primary shoot (no.)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHeight of secondary shoot\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGirth of secondary shoot\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLeaf/\u003c/p\u003e\u003cp\u003esecondary shoot (no.)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eLength of leaf (cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eBreadth of leaf (cm)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e28.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e13.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e14.78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e5.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e2\u003c/sub\u003e: 10 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e30.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e13.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e4.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e3\u003c/sub\u003e: 20 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e30.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e11.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e14.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e5.13\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e4\u003c/sub\u003e: 30 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e32.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e4.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e14.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e5.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e5\u003c/sub\u003e: 40 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e36.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e4.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e6\u003c/sub\u003e: 50 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e40.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e4.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e11.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.75\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e42.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e11.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.53\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSEm (\u0026plusmn;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.462\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.024\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.104\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.051\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.036\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.185\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.072\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCD\u003csub\u003e0.05\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.440\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.073\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.323\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.158\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.112\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.578\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.223\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control), T\u003csub\u003e2\u003c/sub\u003e: 10 Gy (gamma irradiation), T\u003csub\u003e3\u003c/sub\u003e: 20 Gy, T\u003csub\u003e4\u003c/sub\u003e: 30 Gy, T\u003csub\u003e5\u003c/sub\u003e: 40 Gy, T\u003csub\u003e6\u003c/sub\u003e: 50 Gy and T\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eCorms treated with higher doses (T\u003csub\u003e5\u003c/sub\u003e, T\u003csub\u003e6\u003c/sub\u003e and T\u003csub\u003e7\u003c/sub\u003e) (40 Gy, 50 Gy and 60 Gy) of irradiation took more days for bud breaking (36.50 days, 40.25 days and 42.00 days, respectively), and the number of secondary shoots induced per primary shoot was much lower (1.15\u0026ndash;1.25) due to irradiation at 40\u0026ndash;60 Gy [T\u003csub\u003e5\u003c/sub\u003e--T\u003csub\u003e7\u003c/sub\u003e] than at 1.80\u0026ndash;2.65 shoots per primary shoot for the irradiation treatments at 10\u0026ndash;30 Gy [T\u003csub\u003e2\u003c/sub\u003e--T\u003csub\u003e4\u003c/sub\u003e], whereas in nonirradiated control plants [T\u003csub\u003e1\u003c/sub\u003e], the number of secondary shoots induced per primary shoot reached a maximum (2.90). The data depicted in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e indicate that, beyond 40 Gy, the height (8.43\u0026ndash;9.08 cm) and girth (3.80\u0026ndash;4.15 cm) of the secondary shoots were lower than those in the other treatments, whereas at lower doses (10\u0026ndash;30 Gy [T\u003csub\u003e2\u003c/sub\u003e--T\u003csub\u003e4\u003c/sub\u003e]), the height and girth of the secondary shoots ranged from 10.25\u0026ndash;12.44 cm and from 4.60\u0026ndash;5.43 cm, respectively. The leaf number per secondary shoot varied significantly from 2.10 to 2.78 due to the irradiation treatments. The nonirradiated [T\u003csub\u003e1\u003c/sub\u003e] corms (control) recorded the maximum length (14.78 cm) and breadth (5.33 cm) of the leaf, followed by the corms treated with gamma radiation doses of 20 Gy [T\u003csub\u003e3\u003c/sub\u003e] (14.50 cm) and 30 Gy [T\u003csub\u003e4\u003c/sub\u003e] (5.18 cm), whereas the corms treated with a 60 Gy dose [T\u003csub\u003e7\u003c/sub\u003e] of gamma radiation recorded the minimum length (11.25 cm) and breadth (3.53 cm) of the leaf.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Induction and growth of tertiary shoots\u003c/h2\u003e\u003cp\u003eThe data recorded on tertiary shoot induction and growth are presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, which reveals significant variations in the induction time and number of induced tertiary shoots from secondary shoots; the height and girth of tertiary shoots; and the number, length and width of leaves per tertiary shoot. The minimum time (29.00 days) for tertiary shoot induction in the untreated control corms [T\u003csub\u003e1\u003c/sub\u003e] increased to 31.50 to 43.75 days because of the irradiation treatment at different doses (10\u0026ndash;60 Gy). The number of induced tertiary shoots per secondary shoot was lower (1.20\u0026ndash;1.45) due to irradiation at higher doses [T\u003csub\u003e5\u003c/sub\u003e--T\u003csub\u003e7\u003c/sub\u003e] (40\u0026ndash;60 Gy), whereas irradiation at lower doses [T\u003csub\u003e2\u003c/sub\u003e--T\u003csub\u003e4\u003c/sub\u003e] (10\u0026ndash;30 Gy) induced a greater number of tertiary shoots per secondary shoot, ranging from 1.95\u0026ndash;2.90 tertiary shoots per secondary shoot. The untreated control plants [T\u003csub\u003e1\u003c/sub\u003e] produced the maximum number of tertiary shoots per secondary shoot (3.15).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffects of gamma irradiation on the growth of tertiary shoots of macropropagated buds of Martaman banana (AAB) - Time taken for induction; number, height and girth of induced tertiary shoots; number, length and breadth of leaves per tertiary shoot\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTreatment\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDays taken for bud break\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTertiary shoots/secondary shoot (no.)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHeight of tertiary shoot\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGirth of tertiary shoot\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLeaf/\u003c/p\u003e\u003cp\u003etertiary shoot (no.)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eLength of leaf (cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eBreadth of leaf (cm)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e29.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e7.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e2\u003c/sub\u003e: 10 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e31.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e7.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e7.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e3\u003c/sub\u003e: 20 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e32.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e7.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e7.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e4\u003c/sub\u003e: 30 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e34.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e6.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.31\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e5\u003c/sub\u003e: 40 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e37.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e6.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e2.98\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e6\u003c/sub\u003e: 50 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e42.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e1.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e6.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e2.65\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e43.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e1.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e6.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e2.73\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSEm (\u0026plusmn;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.477\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.031\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.094\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.031\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.022\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.105\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.044\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCD\u003csub\u003e0.05\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.486\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.097\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.292\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.097\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.069\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.328\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.137\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eT\u003csub\u003e1\u003c/sub\u003e: 0 Gy (control), T\u003csub\u003e2\u003c/sub\u003e: 10 Gy (gamma irradiation), T\u003csub\u003e3\u003c/sub\u003e: 20 Gy, T\u003csub\u003e4\u003c/sub\u003e: 30 Gy, T\u003csub\u003e5\u003c/sub\u003e: 40 Gy, T\u003csub\u003e6\u003c/sub\u003e: 50 Gy and T\u003csub\u003e7\u003c/sub\u003e: 60 Gy\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe data presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e clearly show that the height and girth of the shoots significantly differed between the control (8.20 cm and 3.49 cm, respectively) and 10 Gy [T\u003csub\u003e2\u003c/sub\u003e]-treated corms (7.89 cm and 3.18 cm, respectively), followed by the 20 Gy [T\u003csub\u003e3\u003c/sub\u003e]-treated corms (7.23 cm and 3.05 cm, respectively). The number of leaves produced per tertiary shoot decreased with increasing irradiation dose. The maximum leaf number (2.43) was recorded for nontreated control corms [T\u003csub\u003e1\u003c/sub\u003e], followed by 10 Gy [T\u003csub\u003e2\u003c/sub\u003e] and 20 Gy [T\u003csub\u003e3\u003c/sub\u003e] (2.35 and 2.32, respectively), whereas the minimum leaf number (2.05) was recorded for 60 Gy-treated corms [T\u003csub\u003e7\u003c/sub\u003e]. The maximum length (7.28 cm) and width (3.50 cm) of the tertiary shoot produced per secondary shoot from 20 Gy [T\u003csub\u003e3\u003c/sub\u003e]- and 10 Gy [T\u003csub\u003e2\u003c/sub\u003e]-treated corms were recorded for the leaves among the irradiated corms, whereas the minimum length (7.28 cm) and width (3.50 cm) were recorded for the corms treated with 60 Gy [T\u003csub\u003e7\u003c/sub\u003e] and 50 Gy [T\u003csub\u003e6\u003c/sub\u003e] doses of irradiation (6.10 and 2.65 cm, respectively). These results are in line with the previous work of Karmakar \u003cem\u003eet al\u003c/em\u003e. (2001), who reported a general decrease in leaf growth with a linear increase in the irradiation dose of gamma rays compared with plantlets with no irradiation treatment.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn the present study, gamma irradiation significantly affected the growth of macropropagated buds of ‘Martaman’ banana (AAB). According to these studies, the growth characteristics decreased in proportion to the increase in gamma-ray exposure. The lethal dose (LD50) for the irradiated corms of banana cv. ‘Martaman’ on the basis of the 50% survival rate and induction of primary buds per corm were 37.71 Gy and 38.95 Gy, respectively. Therefore, 20 Gy and 30 Gy could be used to induce morphological variation among the population of banana cv. ‘Martaman’ multiplied by the macropropagation technique. The results of the present study will provide useful hints for designing mutation breeding programs for improving banana varieties.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor authorship contribution statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTanushree Saha, Soustav Datta, Rahi Masum Reja, Shivaji Chattopadhyay, Sanjit Debnath, Sarthak Bhattacharya: Conceptualization, Investigation, Methodology, Validation, Visualization, Writing \u0026ndash; original draft. Tanushree Saha, Sanjit Debnath, Abdulrahman Alasmari, Lamya Ahmed Alkeridis, Laila A. Al-Shuraym, Ahmed Gaber, Akbar Hossain: Formal analysis, Data curation, Project administration, Supervision, Review and Editing. All authors reviewed the findings and accepted the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was executed at Bidhan Chandra Krishi Viswavidyalaya (BCKV) with financial assistance from the DST-INSPIRE Fellowship, the ICAR-All India Coordinated Research Project (AICRP) on Fruits, and other ad hoc projects, state plan projects and the RIDF-XXIII project.\u0026nbsp;The study also received a partial financial support from Princess Nourah bint Abdulrahman University Researchers Supporting Project (PNURSP2025R82), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors extend their appreciation to Bidhan Chandra Krishi Viswavidyalaya (BCKV) for financial assistance from the DST-INSPIRE Fellowship, the ICAR-All India Coordinated Research Project (AICRP) on Fruits, and other ad hoc projects under investigation, such as Dr. Sanjit Debnath (P.I.), the state plan project and the RIDF-XXIII project. The authors would like to express their gratitude to the collaborative organization (BCKV) for granting the necessary research facilities as well as all the sources of financial assistance. The authors wish to thank Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2025R82), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia, for partially supporting this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing financial interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and/or analysed during the current study will be available from the corresponding author upon request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAbdulhafiz, F., Kayat, F. and Zakaria, S. (2018). Gamma irradiation effect on the growth of Musa cv. Tanduk (AAB). \u003cem\u003eAsian Journal of Agriculture and Biology\u003c/em\u003e, \u003cstrong\u003e6\u003c/strong\u003e(2):135-142.\u003c/li\u003e\n \u003cli\u003eAl-Qurainy, F. and Khan, S. (2009).\u0026nbsp;Mutagenic effects of sodium azide and its application in crop improvement. \u003cem\u003eWorld Applied Sciences Journal\u003c/em\u003e, \u003cstrong\u003e6\u003c/strong\u003e(12):1589-1601.\u003c/li\u003e\n \u003cli\u003eIndian Horticulture Database (2020). Area and Production of Horticulture Crops - All India: 2019-20. \u003cem\u003eIndian Horticulture Database 2019-20\u003c/em\u003e, NHB, MoA, GoI, Gurgaon, Haryana, pp. 1.\u003c/li\u003e\n \u003cli\u003eGomez, K. A. and Gomez, A. A. (1984). Statistical Procedures for Agricultural Research, John Wiley \u0026amp; Sons. Inc. New York.\u003c/li\u003e\n \u003cli\u003eHan, W. and Yu, K. N. (2010). Ionizing radiation, DNA double strand break and mutation. \u003cem\u003eAdvances in Genetics Research\u003c/em\u003e, \u003cstrong\u003e4\u003c/strong\u003e:197-210.\u003c/li\u003e\n \u003cli\u003eKarmarkar, V. M., Kulkarni, V. M., Suprasanna, P., Bapat, V. A. and Rao, P. S. (2001). Radiosensitivity of in vivo and in vitro cultures of banana cv. Basrai (AAA). \u003cem\u003eFruits\u003c/em\u003e, \u003cstrong\u003e56\u003c/strong\u003e(2):67-74.\u003c/li\u003e\n \u003cli\u003eKodym, A. and Afza, R. (2003). Physical and chemical mutagenesis. In: \u003cem\u003ePlant functional genomics: methods and protocols, Methods in molecular biology\u003c/em\u003e, (Ed. Grotewold E; Human Press Inc., Totowa, NJ), pp. 189-203.\u003c/li\u003e\n \u003cli\u003eKumar, N. (2006). Problems and prospects of banana breeding in India. \u003cem\u003eJournal of Horticultural Sciences\u003c/em\u003e, \u003cstrong\u003e1\u003c/strong\u003e(2):77-94.\u003c/li\u003e\n \u003cli\u003eMishra, P. J., Ganapathi, T. R., Suprasanna, P. and Bapat, V. A. (2007). Effect of single and recurrent gamma irradiation on in vitro shoot cultures of banana. \u003cem\u003eInternational Journal of Fruit Science\u003c/em\u003e, \u003cstrong\u003e7\u003c/strong\u003e(1):47-57.\u003c/li\u003e\n \u003cli\u003eOladosu, Y., Rafii, M.Y., Abdullah, N., Hussin, G., Ramli, A., Rahim, H.A., Miah, G. and Usman, M. (2016). Principle and application of plant mutagenesis in crop improvement: a review. \u003cem\u003eBiotechnology and Biotechnological Equipment\u003c/em\u003e, \u003cstrong\u003e30\u003c/strong\u003e(1):1-16.\u003c/li\u003e\n \u003cli\u003ePreussa, S. B. and Britta, A. B. (2003). A DNA-damage-induced cell cycle checkpoint in Arabidopsis. \u003cem\u003eGenetics\u003c/em\u003e, \u003cstrong\u003e164\u003c/strong\u003e:323-334.\u003c/li\u003e\n \u003cli\u003eSales, E., Lopez, J., Espino, R., Butardo, N. and Gonzalez, L. (2013). Improvement of bananas through gamma ray irradiation. \u003cem\u003ePhilippine Journal of Crop Science\u003c/em\u003e, \u003cstrong\u003e38\u003c/strong\u003e(2):47-53.\u003c/li\u003e\n \u003cli\u003eSannigrahi, S. and Debnath, S. (2017). Studies on shoot and root induction of eight commercial banana varieties of West Bengal by macropropagation technique. \u003cem\u003eInternational Journal of Current Research\u003c/em\u003e, \u003cstrong\u003e9\u003c/strong\u003e(6):52426-52429.\u003c/li\u003e\n \u003cli\u003eUma, S., Saraswathi, M. S., Durai, P. and Mahalakshmi, B. (2008). Propagating banana a farmer friendly technology. \u003cem\u003eIndian Horticulture\u003c/em\u003e, \u003cstrong\u003e53\u003c/strong\u003e(5):11-12.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"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":"Banana, mutation, gamma irradiation, LD50, morphological effects, effective dose","lastPublishedDoi":"10.21203/rs.3.rs-7207984/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7207984/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe improvement of commercial triploids of banana through conventional breeding or sexual hybridization has been very difficult due to female sterility, parthenocarpy and polyploidy. Mutation breeding appears to be a promising alternative that may induce the desired variability by altering one or more traits of a usually acceptable cultivar without retaining its original genotype unaltered. Given this background, the present study was designed to determine the radiosensitivity of corm buds and macropropagation of irradiated corms of banana cv. ‘Martaman’ (Musa AAB) with the objective of determining the lethal dose (LD50) for macropropagated buds and optimizing the radiation dose for the induction of putative mutants with one or more desired traits, such as biotic and abiotic stress tolerance or resistance, dwarfness, increased yield or improved fruit quality. Healthy decorticated corms (12–13 cm in diameter) were exposed to various doses of gamma rays (\u003csup\u003e60\u003c/sup\u003eCo) at strengths of 10, 20, 30, 40, 50 and 60 Gy, with an effective dose rate of 04.348 KGy/hr. The control plants received no radiation exposure. The results revealed that the survival rate of corm buds was the lowest (19.50%) due to the irradiation dose of 60 Gy, while it was the highest (96.25%) under the control (without irradiation). The lethal dose (LD50) for the irradiated corms of banana cv. ‘Martaman’ on the basis of the 50% survival rate and number of induced primary buds per corm were 37.71 Gy and 38.95 Gy, respectively, followed by a significant decrease in growth. The growth characteristics decreased in proportion to an increase in the gamma-ray dose. The results suggest that gamma irradiation between 20-30 Gy (below the LD50) could be used to induce morphological variation among populations via the macropropagation technique and the selection of putative mutant plants, which can be used in future breeding programs for the banana cv. ‘Martaman’.\u003c/p\u003e","manuscriptTitle":"Studies on the radiosensitivity of macropropagated corm buds of banana for the improvement of commercial triploid banana cultivars","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-30 08:27:44","doi":"10.21203/rs.3.rs-7207984/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":"705523bc-4159-4809-a327-e4d5206111d9","owner":[],"postedDate":"July 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-16T09:45:44+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-30 08:27:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7207984","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7207984","identity":"rs-7207984","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}