Characterization of rice (Oryza sativa L.) landraces from Majuli and surrounding riverine ecologies in Assam: Assessment of morphogenetic variability and submergence tolerance

AbstractRice landraces from the fragile riverine ecosystems surrounding Majuli islands in Assam are pivotal for local livelihoods, as well as for their potential in developing flood tolerant varieties. We characterized 87 landraces from Majuli, Dhemaji, and North Lakhimpur districts in Assam by assessing 36 agro‐morphological traits, submergence tolerance, and microsatellite diversity. Multivariate analyses revealed that grain and leaf characteristics, plant height, and tillering are important traits differentiating the cultivar types. Sixty‐six SSR markers generated 271 alleles with an average of 4.1 alleles per marker with population structuring in two clusters having an allele frequency divergence of 0.124. The Bao or deep‐water landraces displayed the highest phenotypic and genetic diversity, with potential genetic links to the aus and wild species. Sali (winter rice) and bora (sticky rice) landraces were predominantly indica type. Nearly 47% of the germplasm exhibited tolerance to two‐week submergence at seedling stage. Surveying SUB1A and SNORKEL genes revealed the presence of SUB1A‐1 and SNORKEL genes in 64% and 57% of the tolerant accessions, respectively. This study highlights the untapped potential of rice landraces in a fragile ecological region, providing insights into their agronomical traits, submergence tolerance, and genetic diversity. The findings lay the foundation for improved germplasm management and developing flood‐resilient rice varieties, crucial for sustainable agriculture in riverine ecosystems.