Stem carbohydrate dynamics during post anthesis period in diverse wheat genotypes under different environments

Abstract

The contribution of stem water soluble carbohydrates (SWSCs) to grain biomass of wheat ranges from 10 to 20% under irrigated condition and 40 to 60% under stresses such as terminal heat and drought. Genetic variation in SWSC and its mobilization can be useful to increase the grain yield of wheat under harsh environments. Hence, a set of 16 genotypes varying in spike morphology and grain yield was grown in field under timely sown, late sown and terminal drought stress conditions. The anthrone method was used to measure the SWSC concentration in the dried peduncle and penultimate internodes in three replicates at 3 growth stages starting from anthesis. The effect of delay in sowing and terminal drought on the SWSC concentration was significant from anthesis to 14 days after anthesis. Significant genetic variation was observed in the rate of post anthesis change in SWSC during the early grain filling period under the three conditions which partially contributed to the variation in grain yield per spike among the genotypes. Due to sterile florets and/or shorter grain filling duration, all the genotypes did not have a correlation between grain weight per spike and rate of decrease of SWSCs. Thus, our experiments reconfirm the significance of SWSC in present cultivars of wheat and also the scope for exploiting the genetic variation in this trait.