| Abstract: |
In cotton production, excessive application of nitrogen fertilizers leads to the increasing cost of agricultural production and a large amount of nitrogen loss, causing damage to the environment. Screening cotton cultivars with low nitrogen tolerance is one of the most effective approaches to solve this problem. In this study, 21 cotton cultivars mainly planted in cotton regions were used as the experimental materials, and 23 agronomic traits were measured. The low nitrogen tolerance was evaluated by means of principal component analysis, the fuzzy membership function, cluster analysis, and correlation analysis under normal nitrogen treatment (N 138 mg kg-1) and low nitrogen treatment (N 0 g kg-1) using soil culture experiment at seeding stage. The results showed that the coefficient variation of most indexes were greater than 10%, which indicated that the selected varieties had good representativeness. Based on principal component analysis and correlation analysis, seven traits including root length, root surface area, root volume, shoot dry weight, total dry weight, actual photochemical efficiency, and maximum photochemical efficiency were used as evaluating indices for low nitrogen tolerance of cotton cultivars. Based on the low nitrogen tolerance comprehensive index, four low nitrogen tolerance cultivars (Luwu 403, Xinhai 12, Zhongmiansuo 64, and Xinluzao 23) and five low nitrogen sensitive cultivars (Fengkangmian 1, TM-1, Nongda 601, Zhongmiansuo 35, and Xinluzao 53) were screened out. The low nitrogen tolerance comprehensive index of the four low nitrogen tolerance cultivars ranged from 0.5723 to 0.6817, while the low nitrogen tolerance comprehensive index of five low nitrogen sensitive cultivars ranged from 0.2914 to 0.3962. In summary, the screening method based on the low nitrogen tolerance comprehensive index provided a new reference for the selection of crop cultivars with low nitrogen tolerance. [ABSTRACT FROM AUTHOR] |
