Characterization of Bangladeshi Aus rice landraces under drought stress

Abstract

Genetic diversity is a prerequisite for crop improvement. This study, which was carried out at Patuakhali Science and Technology University, Bangladesh, explored the genetic diversity of 38 Bangladeshi aus rice (Oryza sativa L.) landraces under drought stress by using phenotypic and simple sequence repeat (SSR) markers. Nonhierarchal clustering analysis with Mahalanobis‟ D2 statistic based on the data of morphological traits divided the studied landraces into four groups. High variability was found among the groups. Group 3 had the highest number of tillers per plant, spikelets per panicle, and panicle length. Group 2 had high 100-seed weight, and group 4 showed the highest yield per plant. Spikelets per panicle showed the maximum variation among all of the traits in the four groups. Principal component analysis showed that PC1 contributed 32.24% of the total variation, whereas PC2 accounted for 26.20%. Compared with the other traits, plant height, spikelet per panicle, and yield per plant exhibited a greater influence on the phenotypic variation observed in PC1. Compared with other traits, 100-grain weight, days to harvesting, and days to 50% flowering contributed highly to the variation found in PC2. In SSR analysis, the highest polymorphism information content (PIC) of 0.87 was observed for markers RM207 and RM256 and the lowest PIC of 0.64 was observed for markers RM212 and RM274. „Madab jata‟ showed the highest similarity value (0.7) with „BRRI dhan 42.‟ „Lonka gora binni‟ exhibited a similarity value of 0.588, and „Koba binni,‟ „Parija‟, „Gota irri,‟ „Chitri‟, and „Putiraj‟ presented a similarity value of 0.556 with „BRRI dhan 42‟. Among these genotypes, „Madab jata,‟ „Lonka gora binni,‟ and „Koba binni‟ formed a cluster with „BRRI dhan 42‟ with the coefficient of 0.53. Therefore, „Madab jata,‟ „Lonka gora binni,‟ and „Koba binni‟ might contain drought-tolerant alleles and can be used for future research programs. The high genetic variability obtained in this work indicates that the studied rice genotypes contain drought-tolerant alleles and could be used for breeding drought-tolerant rice cultivars.