Cold tolerance in rice at seedling and reproductive stage

Abstract

Rice (Oryza sativa L.) are normally grown in tropical and temperate climatic zones thought out the country but it has been susceptible by cold stress and it can be affect specially in seedling and reproductive stages during growing periods. Cold stress shows different effects on germination, seedling, vegetative, reproductive and grain maturity and weakens photosynthetic ability by inducing leaf discoloration, reduces plant height, produces degenerated spikes, delays days to heading, reduces spikelet fertility and finally led to reduces poor grain yield. One important strategy for increasing crop productivity is to minimize losses due to abiotic and biotic stresses by developing more stress tolerance varieties. Identification of new genetic sources for cold tolerance is very important for which effective, low cost screening techniques are essential. In this zone quite often the temperature drops below 100C during December and January resulting in poor growth of seedlings of rice crop. The sown Kharif crop will be exposed to low temperature at reproductive stage. This study aims to identify a suitable technique to estimate rice cold tolerance at the germination stage and identify the variability among 39 genotypes and these genotypes were evaluated to assess cold tolerance based on seedling and reproductive character in the field, under cold during late Kharif, 2015-2016 and this experiment was conducted in Randomized Block Design at Rice Research Scheme, Agricultural Research Institute, Rajendranagar.