Evaluation of rice (Oryza sativa L.) genotypes for cold tolerance at seedling stage

Abstract

Cold tolerance during germination is important for ensuring fast and uniform crop establishment. Rice plants are injured at the seedling stage when they are grown in early spring in temperate or subtropical environments. The productivity of rice is particularly low during spring due to cold, which is an important abiotic constraint, where low temperature prevails below 18 ºC. The present study was taken up to evaluate cold tolerance in 86 rice genotypes based on seed and seedling parameters as per Cruz and Milach (2004). Seeds were germinated under two conditions i.e.,160C for 28 days (cold) and 280C for 7 days (control).The genotypes showed highly significant differences forparameters such as germination (%), germination index (%), percentage of seeds with coleoptile superior to 5 mm (PERCOL), percentage of reduction in coleoptile length (REDCOL) and coleoptile regrowth (COLREG, cm).Both REDCOL and COLREG seem to be the most adequate characteristics to be used to evaluate cold tolerance during the germination period in rice. Among those genotypes, AC 35548, JBT 37/164, PS 353, KMP-175 andThanu were adjudged as promising when screened for cold tolerance under laboratory conditions based on the aforementioned parameters.

Germin Like Protein Genes Exhibit Modular Expression During Salt and Drought Stress in Elite Rice Cultivars

“…Both of these stress factors affect the developmental process of plants by osmotic shock and subsequent oxidative stress, however, salt stress has an added deleterious impact of ionic toxicity and nutrient imbalance [16]. Moreover, the effect of salt and drought stress in rice is greatly dependent on the growth period: early seedling stage of rice is potentially among the most sensitive stages for the imposition of both stress conditions [17][18][19]. Considering this aspect, the analysis of expression dynamics of stress responsive GLP genes in rice (OsGLP) at early seedling stage can be useful for screening the stress tolerance of different rice varieties.…”