Synthetic allohexaploid Brassica are able to express best-parent traits in response to drought

Synthetic allohexaploid Brassica are able to express best-parent traits in response to drought | 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 Synthetic allohexaploid Brassica are able to express best-parent traits in response to drought Tiegist D. Abebe, Angela Adjei, Helen Behn, Agim Ballvora, Annaliese S. Mason This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8977270/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 Many species are allopolyploid, containing sets of chromosomes from multiple different species. Ploidy increase may also confer resistances to specific stresses, but few studies have specifically tested allopolyploid hybrids in comparison to their exact parent species genotypes for abiotic stress response. However, the impact of drought-induced stress on the productivity, germination, and chlorophyll levels of Brassica crops have been extensively studied. Here, we aimed to test whether novel allohexaploid hybrids between Brassica species show better drought tolerance than their parent allotetraploids. We tested two allohexaploid lines and each of their three parent genotypes of Brassica species ( B. carinata , B. juncea , and B napus ) for photosynthetic response and phenotypic traits under drought stress (approximately 20% water field capacity) and well-watered control conditions. Physiological parameters including chlorophyll fluorescence, normalized vegetative index, chlorophyll content, Stress Tolerance Index (STI) and leaf wilting were assessed at four time-points during stress endurance. Chlorophyll fluorescence was the physiological trait that showed the most significant variation between drought and control treatments. Out of the two synthetic allohexaploids N6C2J2 performed better than the best parent J2 for most of the physiological traits and for leaf wilting, although not for number of seeds per plant. By contrast, N1C1J1 showed poor performance but was still better than the worst parents J1 and C1 for most traits. Our study suggests that allohexaploid Brassica shows promising potential to contribute in drought stress tolerance breeding, but that genotype-specific effects likely play a major role in any observed phenotypic advantages of novel allopolyploids. Plant Molecular Biology and Genetics Plant Physiology and Morphology Photosynthesis abiotic stress polyploid advantage allopolyploid Full Text Additional Declarations The authors declare no competing interests. Supplementary Files SupplementaryFigures.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8977270","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":597516816,"identity":"8d1d4aed-02b5-465f-a0ab-531465697c61","order_by":0,"name":"Tiegist D. 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Ploidy increase may also confer resistances to specific stresses, but few studies have specifically tested allopolyploid hybrids in comparison to their exact parent species genotypes for abiotic stress response. However, the impact of drought-induced stress on the productivity, germination, and chlorophyll levels of \u003cem\u003eBrassica\u003c/em\u003e crops have been extensively studied. Here, we aimed to test whether novel allohexaploid hybrids between \u003cem\u003eBrassica\u003c/em\u003e species show better drought tolerance than their parent allotetraploids. We tested two allohexaploid lines and each of their three parent genotypes of \u003cem\u003eBrassica\u003c/em\u003e species (\u003cem\u003eB. carinata\u003c/em\u003e, \u003cem\u003eB. juncea\u003c/em\u003e, and \u003cem\u003eB napus\u003c/em\u003e) for photosynthetic response and phenotypic traits under drought stress (approximately 20% water field capacity) and well-watered control conditions. Physiological parameters including chlorophyll fluorescence, normalized vegetative index, chlorophyll content, Stress Tolerance Index (STI) and leaf wilting were assessed at four time-points during stress endurance. Chlorophyll fluorescence was the physiological trait that showed the most significant variation between drought and control treatments. Out of the two synthetic allohexaploids N6C2J2 performed better than the best parent J2 for most of the physiological traits and for leaf wilting, although not for number of seeds per plant. By contrast, N1C1J1 showed poor performance but was still better than the worst parents J1 and C1 for most traits. Our study suggests that allohexaploid \u003cem\u003eBrassica\u003c/em\u003e shows promising potential to contribute in drought stress tolerance breeding, but that genotype-specific effects likely play a major role in any observed phenotypic advantages of novel allopolyploids.\u003c/p\u003e","manuscriptTitle":"Synthetic allohexaploid Brassica are able to express best-parent traits in response to drought","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-27 15:14:47","doi":"10.21203/rs.3.rs-8977270/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":"a3459c9d-fca6-4c16-b2b2-69b3d95418fc","owner":[],"postedDate":"February 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":63582969,"name":"Plant Molecular Biology and Genetics"},{"id":63582970,"name":"Plant Physiology and Morphology"}],"tags":[],"updatedAt":"2026-02-27T15:14:47+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-27 15:14:47","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8977270","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8977270","identity":"rs-8977270","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}