Phenotypic diversity analysis and comprehensive evaluation of 397 sorghum germplasm resources in Guizhou, China

To address the challenges of limited varietal diversity and germplasm degradation in Guizhou sorghum production, this study systematically evaluated the phenotypic diversity of 397 sorghum accessions under local ecological conditions, aiming to identify well-adapted germplasm resources and provide a theoretical foundation for genetic improvement and breeding. From 2023 to 2024, 15 phenotypic traits were assessed in Guiyang, Guizhou, using genetic diversity indices, correlation analysis, principal component analysis (PCA), cluster analysis, and broad-sense heritability estimation. Elite accessions were selected based on comprehensive F values and target traits. The accessions exhibited rich phenotypic variation, with Shannon-Wiener indices ranging from 0.919 to 2.052. Panicle shape showed the lowest diversity, while plant height displayed the highest. Plant height and growth period had the highest broad-sense heritability, indicating strong genetic control. Domestic accessions outperformed foreign ones in stem diameter, panicle length, and grain length, whereas foreign accessions were superior in dwarfism and 1000-grain weight. Correlation analysis revealed that panicle type and panicle shape were extremely significantly and positively correlated, and both were highly positively correlated with panicle length and plant height, but were extremely significantly and negatively correlated with the number of cob nodes, 1000-grain weight, and grain width. Plant height was extremely significantly and positively correlated with growth period, stem diameter, internode number, and panicle length. In addition, 1000-grain weight was extremely significantly and positively correlated with grain width, and glume color with grain color. PCA extracted four principal components (eigenvalues > 1), accounting for 66.43% of the total variance, corresponding to panicle morphology and plant height, grain yield, growth characteristics, and grain appearance quality. Cluster analysis grouped the accessions into five categories. Group IV, characterized by dwarf stature, high 1000-grain weight, and compact architecture, was suitable for dense planting and high yield; Group V, with tall plants and broom-shaped panicles, was suitable for industrial applications. Twenty elite accessions—including Erluhuangke, Hongmaonuo 2, Tiangaoliang (Xuanwei), B martin, and GL002—were selected based on comprehensive evaluation. In conclusion, the 397 sorghum accessions exhibited substantial phenotypic diversity under Guizhou conditions. Plant height and growth period, showing high genetic stability, represent key target traits for genetic improvement. The selected elite germplasms possess complementary trait profiles and offer valuable parental resources for diverse breeding objectives.