Evaluation of Drought Resistance and Quality of Different Rice Hybrid Combinations

Abstract

Rice is an integral component of the daily food consumptions in China. Drought stress diminishes rice productivity and deteriorates its quality. To further improve the identification and selection system of drought-tolerant rice variet - ies, this experiment used 130 new rice hybrid combinations as research materials and water stress was carried out during the whole life span, with normal water management as the control, so as to construct a synergistic evaluation standard of drought-tolerance of rice in terms of yield and quality by examining the characteristics of plant height, fruiting rate, yield per plant, and quality. The study showed that (1) the coefficients of variation of the drought toler - ance coefficients of the 11 indexes ranged from 3.50% to 44.35%, with the largest coefficient of variation being the yield per plant at 44.35% and the smallest being the grain length at 3.50%. According to the principal component analysis, the cumulative contribution of the first four principal components was 73.022%, which were the total num - ber of grains, the number of solid grains, the effective panicles and plant height. The correlation analysis showed that the drought tolerance composite evaluation value was extremely significantly correlated with plant height, effective panicles, total grain number, number of solid grains, fruiting rate, thousand grain weight and grain width. Based on the results of stepwise regression analysis, the number of grains, plant height and thousand grain weight can be used as drought-resistant identification indexes. (2) Based on the variation characteristics of protein, brown rice rate, re - fined rice rate, whole refined rice rate and straight-chain starch content, 50 high-quality combinations were selected. The results of cluster analysis showed that the 50 rice combinations were divided into three groups, Group I strong drought-resistant with materials HD009, HD024, HD171, HD207, HD432, HD447, HD0451, a total of 7 materials up to the first level of rice indicators; Group II medium drought-resistant with 21 materials up to the first level of rice indicators; Group III drought-sensitive material HD522 up to the first level of rice indicators.