Abstract:To explore the composition characteristics of protein and 17 kinds of amino acids (excluding Trp) in wolfberry leaves from different producing areas, varieties and harvesting seasons in Ningxia, a total of 143 samples of 6 wolfberry varieties were collected from four producing areas (Guyuan, Zhongning, Huinong and Yinchuan) in summer and Zhongning in autumn. The contents of protein and amino acids were determined, and their composition proportions were calculated. Correlation analysis and principal component analysis (PCA) were used for comprehensive evaluation. The results showed that producing area and harvesting season significantly affected the total protein and amino acid contents of wolfberry leaves, and differences still existed among varieties under the same producing area and harvesting condition. The protein mass fractions of five area?harvest combinations ranged from 15.82 to 24.22 g/100 g, and the total contents of 17 amino acids ranged from 14.42 to 23.18 g/100 g, with the highest values in autumn Zhongning samples and the lowest in summer Yinchuan samples. Glutamic acid (Glu) and aspartic acid (Asp) were the dominant amino acids, reaching approximately 2.89 g/100 g and 2.47 g/100 g in autumn Zhongning samples, respectively. The EAA/TAA of each group was 39.63%–41.78%, with small intergroup variation. PCA revealed that PC1 of absolute?content?based PCA accounted for 84.4% of total variance, while PC1 of proportion?based PCA only accounted for 22.7%. Producing area and harvesting season mainly regulated the absolute contents of amino acids, whereas amino acid composition ratio remained relatively stable. Most amino acids showed significant positive correlations, and sulfur?containing amino acids (Met, Cys) had weak correlations with other amino acids. This study can provide basic data for the evaluation, development and utilization of wolfberry leaf resources.