Screening of boro rice varieties of Assam, India to estimate their potential resistance to cold and heat stresses

Temperature stress is a major concern in the agricultural practices due to the changing global climatic condition. The present investigation was conducted to evaluate cold and heat tolerant ability of few boro rice cultivars of Assam, India. Based on the different morpho-physiological responses under heat and cold stresses, 27 boro rice cultivars showed varying degrees of susceptibility. The total stress response index (TSRI) calculated on the basis of morpho-physiological parameters identified Buro as the most tolerant variety under both cold and heat stress. In contrast, Disang and Swarnabh were found to be the most susceptible cultivars under both the stresses. Our findings suggest that morpho-physiological traits are useful in screening rice varieties under environmental stress and TSRI can prove to be a suitable marker for developing promising heat and cold tolerant rice varieties in further rice breeding programs.