Diversity Analysis and Comprehensive Evaluation of Agronomic Traits in Perennial Chinese Rice Germplasm for breeding

Perennial Chinese rice is a novel type of rice germplasm native to China. This study comprehensively evaluated the variation in the agronomic traits of 20 perennial Chinese rice germplasm across four different planting seasons to explore the genetic diversity of perennial Chinese rice and effectively utilize them. A total of 16 agronomic traits, including heading date, plant height, and thousand-grain weight, were investigated based on the field phenotypic values. The findings revealed significant variations among these traits with a broad range of Shannon–Wiener indices, which ranged from 1.46 to 3.33 in 2021MC, 1.49 to 1.96 in 2021RC, 1.50 to 2.10 in 2022MC, and 1.31 to 2.10 in 2022RC. The coefficients of variation among 16 traits ranged from 4.40–64.34% in 2021 MC, 5.53–74.24% in 2021RC, 3.91–56.90% in 2022MC, and 3.55–92.57% in 2022RC. The 20 germplasm were divided into five distinctive clusters in 2021MC, 2021RC, and 2022MC and six distinctive clusters in 2022RC based on the analysis of hierarchical clustering, but divided into six categories by 13 pairs of SSR primers with good polymorphism. The M-TOPSIS exhaustive evaluation method based on correlation and the principal component analysis (PCA) of 16 traits was applied for the 20 germplasm, and the top one germplasm LN1 that displayed stable field performance on agronomic traits was screened repeatedly across four different planting seasons and adapted to the ecological areas of Chongqing in Southwest China. This study will provide a reference for the screening of potential perennial rice germplasm and the further research on perennial rice genetics and breeding.