Genetic variability of panicle architecture in indigenous rice (Oryza sativa) landraces of Southern region of Bangladesh

Indigenous rice landraces are crucial genetic resources with unique traits that enhance crop productivity. In this study, 50 indigenous rice landraces were grown in the Agronomy field at Patuakhali Science and Technology University following Randomized Complete Block Design. Based on panicle architecture, their genetic diversity and adaptability were examined considering the genotypic and phenotypic variability, heritability, genetic advance, and distinctive correlations. Evaluated characters were exhibited different levels of variability, heritability and genetic advance among the studied genotypes. Higher phenotypic coefficient of variation (PCV) than genotypic coefficient of variation (GCV) for all traits reveals significant environmental effect. The highest heritability estimates for 100-seed weight (98.3%) and lowest for panicle length (51.7%), reveal effective genetic control. Additionally, the highest genetic advance (GA) was noted for the number of grains/panicle (117.24), which also revealed the greatest genetic advance as a percentage of mean (GAM) (63.79%). Importantly, significant variations were found for key traits, including panicle length, flag leaf area, and grains per panicle. Moreover, genotypic correlations revealed positive relationships between dry grain weight and leaf area (r = 0.539), panicle length (r = 0.161), and grains per panicle (r = 0.711). Principal component analysis identified grain, dry weight, and panicle numbers as major contributors to overall variability. Hierarchical clustering grouped genotypes by similarity, with Fatema excelling across multiple traits. BRRI-34, Dishari, Khir mota, Loha gura, Shukno mota, Motha mota, Balam chikon, and Shada mota, among others, are crucial for breeding to introduce new traits. Therefore, these findings may add the value of indigenous rice landraces as a crucial genetic resource for developing improved rice varieties with enhanced yield and stress resilience.