Comprehensive evaluation of drought resistance in the Vicia sativa germplasm at the seedling stage

The selection and evaluation of drought-resistant germplasm resources are the basic steps in the breeding of drought-resistant varieties. The identification of drought resistance, determination of evaluation methods and indexes, and screening of high drought resistance germplasms can provide the basic materials for the breeding of drought-resistant Vicia sativa varieties. The drought-resistant of 52 V. sativa germplasms at the seedling stage were comprehensively evaluated using a recurrent drought method under greenhouse conditions. The results showed that drought stress significantly reduced the plant height, shoot fresh and dry weight, root fresh and dry weight, shoot/root ratio, and nodule number. The correlation analysis showed that the shoot fresh and dry weight had was significantly positively correlated with plant height but significantly negatively correlated with root fresh and dry weight and shoot/root ratio. Five principal components were extracted, and they accounted for 86.33% of the cumulative contribution rate. Basic on the D value, all the tested germplasms were divided into 5 drought resistance grades: High drought resistance, drought resistance, moderate resistance, sensitive resistance, and high sensitivity. VS35, VS34, VS30, and VS21 had the highest drought resistance among all germplasms and could be used as parental materials for the breeding of drought-resistant varieties. Although VS16, VS28, VS27, and VS46 had the lowest drought resistance, these germplasms could be used in the study of drought resistance mechanisms and regulatory mechanisms. The shoot biomass and plant height were strongly correlated with drought resistance and represent important identification indices for drought resistance evaluations of V. sativa at the seedling stage.