Abstract:

This study systematically evaluated the fruit quality characteristics of mulberry germplasm resources, aiming to screen germplasm with superior comprehensive traits and provide a scientific basis for mulberry variety improvement and industrial development. A total of 38 mulberry germplasm accessions were used as research materials, and 18 fruit quality traits covering appearance, texture, flavor, nutritional quality, and functional quality were measured and analyzed. A comprehensive evaluation was then conducted by integrating variation analysis, correlation analysis, cluster analysis, factor analysis, and membership function analysis. The results showed abundant variation in fruit quality traits among the tested mulberry germplasm resources. The coefficient of variation ranged from 11.95% to 52.16%, and the functional indexes such as vitamin C and total proanthocyanidins had the most significant variation, and the degree of variation in nutritional and functional quality traits was significantly higher than that in appearance, texture, and flavor quality traits. Correlation analysis revealed varying degrees of correlation among the traits, with fruit size showing a negative correlation with total soluble sugar content, while polyphenol compounds exhibited a significant positive correlation with antioxidant activity. Through cluster analysis, the tested germplasm resources were divided into seven groups. Among these, Group I (including ‘98-12’, etc.) was the largest in proportion and exhibited the highest juice yield; Group II (‘Guoxuan04-122’) was characterized by high organic acid and high vitamin C content; Group III (‘97-139’) showed high fruit firmness; Group IV (including ‘Jiedong1’, etc.) demonstrated outstanding functional quality; while Group VII (‘Yueyou152’) was distinguished by its large fruit size and high sugar content. Factor analysis extracted five principal factors with a cumulative variance contribution rate of 85.636%, revealing the intrinsic structural characteristics of the fruit quality traits. Based on this, a comprehensive evaluation integrating the membership function method and factor analysis was conducted, leading to the identification of five germplasm resources with superior comprehensive traits: ‘Yuyou03-351’, ‘44-5’, ‘Jiedong1’, ‘Yueyou35’, and‘Yueyou152’. This study systematically elucidated the patterns of fruit quality variation in mulberry germplasm resources and established a multi-indicator comprehensive evaluation system. The selected elite germplasm can serve as parental material for mulberry breeding, and the research findings hold significant theoretical and practical importance for promoting the high-quality development of the mulberry industry.

Key words: mulberry, germplasm resources, fruit quality evaluation, correlation analysis, cluster analysis, factor analysis, membership function analysis, elite germplasm screening