Effect of endogenous gibberellic acid content on physiological and yield related traits in late sown wheat

Terminal heat stress is becoming major factors in limiting wheat production with increasing evidence of heat stress in present scenario of climate change. Plant hormones are key player in determining plant response to these stresses from perception of stress to final adoptive response. Gibberellic acid is one of the major plant hormone playing crucial role in plant development from germination to seed development, but there is huge gap in knowledge about its role under heat stress. Present study was conducted in late sown wheat (i.e. on 5th January)to examine the inter-relationship between leaf gibberellic acid (GA3) level at reproductive stage with physiological and yield related traits under heat stress in 40 wheat genotypes. Genotypes were categorized into three classes namely tolerant, intermediate and sensitive based on heat stress tolerance ability for further analysis. The diversity in endogenous GA3 concentration was found among the cultivars. The unique inverse relationship between GA3 level in flag leaf and tolerance level of genotypes was found in this study through regression analysis (p<0.05). The path analysis showed that GA3 had direct negative influence on test weight under heat stress conditions. Thus, investigations of mechanism of GA3 influence on sink capacity have the potential to develop heat tolerant genotype and increase wheat production under heat stress.