Abstract

Rice production is being threatened by increase in temperature around the globe. This is affecting the production and productivity of the crop. Changing climate scenario demands the need to identify thermotolerant genotypes to be used as donor in future breeding programmes. The effect of high temperature from panicle initiation to maturity was imposed in twenty-six rice genotypes. The difference in mean monthly maximum and minimum temperature was 3.5 oC and 1.4 oC, respectively between the polyhouse and ambient control. Results revealed a reduction in important physiological traits viz., membrane thermostability as well as chlorophyll content. Of the genotypes tested, MTU 1290, MTU 1153, MTU 1156, JB 683-1, N22 and IL 19211 maintained a higher stability of membranes and lesser reduction in chlorophyll content when exposed to high temperature stress. High temperature resulted in reduction of grain yield as well as yield attributes in rice genotypes. The above genotypes also had a higher spikelet fertility and lesser yield penalty when exposed to high temperature. The results indicated that these genotypes could be selected as thermotolerant and could serve as potential donors for future breeding programmes.