Objective To characterize the response of different peanut cultivars to nitrogen.
Method A total of 81 peanut cultivars from all over China were used as materials, and two field treatments of normal nitrogen application and low nitrogen application were set up. Nineteen indexes, including chlorophyll content at the seedling stage as well as yield, dry matter accumulation and agronomic traits at the harvest stage, were measured in 81 peanut cultivars. The nitrogen response coefficients of the measured 19 indicators were used as the basis for principal component analysis, six new independent composite indicators were screened out, and the D values for comprehensive evaluation of peanut nitrogen sensitivity were obtained by calculating their affiliation function values and the weights of each composite indicator. The peanut cultivars were classified by cluster analysis. The correlations between nitrogen response coefficients and indicators of different types of peanut cultivars were further analyzed.
Result The 81 peanut cultivars were divided into nitrogen-sensitive (13), intermediate (33) and nitrogen-insensitive (35) cultivars. Under normal nitrogen application treatments, the response of nitrogen-insensitive peanut cultivars did not differ significantly in agronomic traits, but the increase in yield and dry matter accumulation of nitrogen-sensitive and intermediate peanut cultivars were significantly higher than those of nitrogen-insensitive cultivars. Correlation analysis of different traits showed that nitrogen application mainly affected peanut yield formation by influencing peanut dry matter accumulation and distribution and plant structure.
Conclusion Chlorophyll content at seedling stage, single plant productivity and dry matter accumulation at harvest stage can be used as screening indicators for peanut nitrogen-sensitive cultivars, and the results of the study can provide a basis for screening and breeding of nitrogen-efficient cultivars of peanut.
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