Madan, ShashiMahla, Reena2017-06-032017-06-032013http://krishikosh.egranth.ac.in/handle/1/5810014743The present investigation was conducted to investigate the effect of drought stress on starch metabolism in late sown wheat (Triticum aestivum L.) during grain development. The four genotypes i.e. two tolerant (WH 1021 and WH 1080) and two susceptible (WH 711 and HD 2687) were raised in late sown conditions under irrigated and drought stress conditions. Drought stress was created by withholding the irrigation at anthesis stage. Analysis of data reavealed that during grain development, starch metabolising enzymes i.e. sucrose synthase, ADP-glucose pyrophosphorylase, soluble starch synthase, starch branching and starch debranching enzyme increased in all genotypes and reached their peaks but their maximum peak values and time at which they reached were different in different genotypes. Increase in sugar content was found under drought stress conditions in comparison to irrigated conditions at different days after anthesis. Water stress caused a marked reduction in starch content of grains. In all genotypes level of ADP-glucose and UDP-glucose increased up to 21st DAA and then declined. Physiological parameters like relative water content, osmotic potential, chlorophyll content, chlorophyll fluorescence, cell membrane thermostability and canopy temperature depression declined under drought stress conditions over irrigated conditions. Quality parameters like moisture content and crude fibre decreased whereas, sedimentation value, gluten, protein content and grain hardness increased under drought stress condition over irrigated conditions. Yield parameters like grain number per spike, grain weight, number of productive tillers, biomass per plot and grain yield decreased under drought stress. The reduction in physiological, biochemical, yield and grain quality traits was found to more pronounced in the susceptible genotypes in comparison to the tolerant ones. WH 1021 was adjudged to be most tolerant genotype.enLate sown wheat, Developing grains, Starch, Proteins, Enzymes, Quality, Yield, Physiological parameters, Drought stressThesis