Genetic variation of phenotypic plasticity in Bangladesh rice germplasm

Abstract

Abstract Active selection of phenotypic plasticity has the potential to increase agricultural crop productivity. We screened 208 Bangladeshi rice genotypes in Bangladesh in 2015 for their phenotypic plasticity with respect to panicle dry weight per hill (PDW) relative to planting geometry, which alters solar radiation captured by leaves due to differences in mutual shading. The plasticity of PDW relative to planting geometry (ratio of panicle dry weight at half density/normal density) varied by genotypes ranging from 0.82 to 2.56 times with an average of 1.59 times. Most of the variation in PDW was explained by the plasticity of total dry weight and panicle number, rather than individual panicle weight and harvest index. We selected 10\u202fgenotypes with the best and worst phenotypic plasticity for PDW. These candidate genotypes were tested for their plasticity in six different environments in 2016. The Finlay-Wilkinson regression coefficient for PDW was 1.09 for the best group compared to 0.87 for the worst group although large variation existed within each group. The mean PDW averaged for all environments was 8% greater for the best group compared to the worst one. Two genotypes “Chini sagar” and “Koha binni” with highest plasticity and productivity could be candidate donor varieties for future breeding programs. These results indicated that phenotypic plasticity is a heritable trait, and therefore a useful indicator for improving crop productivity for any expected climate change.