Horticulture and Quality Traits with Local Germplasm Resources of Capsicum annuum in Xizang

Purpose To reveal the horticultural and quality traits of local capsicum germplasm resources in Xizang, thereby laying the germplasm foundation for capsicum breeding.

Methods A total of 34 purified and rejuvenated local capsicum germplasm resources from Xizang were used as materials, six horticultural traits and seven quality traits of chili fruits were compared and analyzed. Correlations among the quality traits was examined, and the relationships among different chili germplasm resources were explored through principal component analysis (PCA) and cluster analysis.

Results The coefficients of variation for horticultural and quality traits of pepper fruits were the highest for single fruit weight and capsaicin content (0.41 and 0.43, respectively). Among the quality traits, soluble sugar showed an extremely significant positive correlation with cellulose, while soluble protein exhibited a significant negative correlation with capsaicin. PCA showed that the seven quality traits could be extracted into three principal components, with a cumulative contribution rate of 67.96%, which could represent most of the information of the capsicum fruit quality traits. Cluster analysis classed the 34 capsicum germplasm resources into three groups: high-carotenoid group (YG3, LZ, LY, JL, DX2, HD2, BX, JX, DM, YG1, GX, LX), comprehensive high-quality group (PL, MZK, SDX, RJ, HD3, DR2, HD1, GL, DR1, DX1, TM, MT4), and high capsaicin and ascorbic acid group (MB, LB, ML, MT1, MT2, MT3, MT5, XCY, XYD, YG2).

Conclusion The local capsicum germplasm resources in Xizang have distinctive characteristics. JL and HD3 are high-yield and mildly spicy types, while MZK, GL, SDX, RJ, HD2, and MT1 are medium-to-high-yield and extremely spicy categories. These provide an important germplasm foundation for capsicum breeding with different objectives.