Response of different peanut varieties to drought stress

A total of 29 peanut varieties (lines) were planted in North China under artificially controlled moderate soil water stress conditions. Peanut growth rate and content of photosynthetic pigments were investigated to analyze drought resistance mechanisms and screen drought resistant genotypes. The results showed that different peanut varieties (lines) responded differently to the degree and time of soil water stress. Both the degree and time of water stress significantly influenced the morphological, physiological and biomass characteristics of peanut. Under moderate soil water stress, shoot growth in peanut was obviously inhibited. Main stem height and shoot biomass dropped significantly under moderate soil water stress. With prolonged stress period, main stem height decreased significantly. At maturity, stress index of main stem height and biomass of some peanut varieties (lines) dropped by 65%~70%. Root-to-shoot ratio, photosynthetic pigment content and specific leaf area increased under soil water stress at pod-producing and plump-pod stages. This trend also significantly increased with prolonged stress period. With the exception of branch number and carotenoid content, all other indices were usable in the identification of drought resistance of peanut varieties (lines) at pod producing stage. High drought tolerant varieties (lines) of peanut included “Jihua 4”, “Huayu 22”, “Huayu 24”, “Huayu 20”, “Huayu 21”, “Huayu 25”, “Tangke 8”, “Huayu 17” and “Huayu 27”.