Estimating and screening of drought resistance indexes of peanut

Abstract

Aims Our objective was to define an index of peanut (Arachis hypogaea) drought resistance and comprehen- sively evaluate drought resistance of peanut varieties under controlled water conditions. Methods The experiment was conducted on the farm of Qingdao Academy of Agricultural Science with 29 pea- nut varieties. Two levels of water content (80%-85% and 45%-50% of field moisture capacity) were used in a randomized complete block design with four replications. We measured 13 morphological and physiological characters such as plant height, branch numbers, biomass, leaf water content and photosynthetic pigment content in seedling and pod-pin stages. Important findings The 29 peanut cultivars can divided into four classes: high-, mid- and low-tolerant cultivars and intolerant cultivars. The high-tolerant cultivars included 'Tangke 8', 'Jihua 2', 'Datangyou', 'Huayu 25', 'Huayu 17', 'Luhua 14' and 'Fenghua 1'. Subordinate function values of the morphological indexes including main stem height, branch number and biomass, and photosynthetic pigments contents of the same cultivars at seedling stage were different. In addition, the subordinate function value of the seedling stage was unrelated to drought resistance, so a single physiological index cannot be used to identify the drought resistance of peanut. But the values drought resistance comprehensive evaluation (D) of physiological indexes were significantly related to drought resistance and can be used to identify the drought resistance of peanut. At the pod-pin stage, the D values of morphological indexes and physiological indexes were both significantly related to drought resistance, so the