Tolerance Profiling of Selected BRRI Rice Varieties Against Pre-Harvest Sprouting

Abstract

Pre-harvest sprouting (PHS) of grains while attached to the mother plant before harvest is a major threat to lowland rice production in Bangladesh, especially in the high rainfall period at the harvesting stage. The study aimed to assess varietal differences in PHS tolerance of 35 BRRI rice varieties. A modified water-soaking technique was used to enhance PHS at 25 and 30 days after flowering (DAF). Significant variations were observed among the varieties underlying the inherent properties of PHS tolerance. At 25 DAF, most of the varieties exhibited less than 5% germination, which increased at 30 DAF. BR16, BR19, BRRI dhan36, BRRI dhan45, BRRI dhan48, BRRI dhan55, BRRI dhan84, and BRRI dhan88 showed high tolerance to PHS in both the growth stages. BRRI dhan50, BRRI dhan86, and BRRI dhan89 exhibited high susceptibility (>50% PHS). There was a strong positive correlation between PHS percentage and reduction in 1000-grain weight after 30 DAF. Clustering and principal component analysis (PCA) analysis showed that PHS tolerance is strongly dependent on genotype and seed maturity stage. PHS-tolerant BRRI rice varieties could be used as parent materials for breeding sprouting-resistant variety development. It is better to adjust the planting window for BRRI dhan50, BRRI dhan86, and BRRI dhan89 varieties so that they can avoid high rainfall during the harvesting stage.