Low light (LL) stress is an important abiotic stress of wet season which adversely affects starch biosynthesis and results in drastic reduction in rice grain yield. In general, the grain yield decreases together with reduction in the amylose (AC) and resistant starch (RS) contents while the glycemic index (GI) values increased in plants exposed to LL stress. This is the first report of the effect of LL stress on RS and GI values. In the present investigation, 14 rice genotypes are studied for the effect of LL stress on AC, RS, and GI of the grains. Rice genotypes, Purnendu and Shashi differ in exhibiting relatively much lower reduction in AC and RS and hence little change in their GI values under LL stress, while wide variation is observed for the rest of the genotypes. The grain yields of Purnendu and Shashi are also not much affected by the LL stress. There is a dramatic increase in the expression levels of the gbssI in the middle stage of grain development in the two genotypes (Purnendu and Mahisugandha with contrasting RS, AC, and GI). Maximum expression of the gene was observed in Purnendu at middle stage showing a positive correlation between RS and gbssI expression. As rice is grown mainly in wet season, the identification of rice genotypes which do not permit much change in RS value when grown under LL and hence no significant increase in the GI value, would help to develop better rice varieties for consumption by diabetics.

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Seven species of oat (Avena) were evaluated for their relative drought tolerance under soil moisture stress. The plant height, leaf area production and biomass yield reduced under soil moisture stress. Among the species tested, minimum reduction in height was recorded in Avena vaviloviana, Avena abyssinica and Avena sterilis at vegetative and flowering stages. Significant decrease in leaf area production was recorded at vegetative stage, whereas at flowering stage, the decrease in leaf area production was marginal in A. sterilis followed by A. abyssinica predicting their more adaption to stress environment. The increase in specific leaf weight (SLW) of all the species of Avena showed increase in leaf thickness, exhibiting high water retention capacity under soil moisture stress condition which is a requisite trait for drought tolerance. Soil moisture stress imposed at vegetative and flowering stages reduced fresh biomass yield in all the species. Minimum reduction in dry biomass accumulation under stress environment at vegetative stage was recorded in A. sterilis followed by A. strigosa and A. sativa, exhibiting their tolerance to drought at early stages of growth. However, at flowering stage, minimum decrease in dry biomass production was recorded in A. sterilis (3.47%) followed by A. marocana (12.56%) indicating their relative drought tolerance at flowering stage of crop growth. A significant positive correlation between total leaf area and dry biomass (r 2 =0.738) under stress environment indicates that dry biomass accumulation was governed by total leaf area production. A. sterilis accumulated maximum fresh and dry biomass under soil moisture stress with minimum reduction over the non stress environment, indicating its drought tolerance potential as compared to other genotypes tested.