Genetic diversity of inner quality and SSR association analysis of wild kiwifruit (Actinidia eriantha)

In order to establish the link between fruit quality traits and genotypes with specific allelic variations, one hundred and forty five wild kiwifruit (A. eriantha) germplasm resources were used to evaluate the fruit quality, and their SSR markers were used to analyze the genetic diversity and also the correlation between the natural variation of their main inner qualities and SSR markers in this study. The results showed that there were abundant variations in the main inner quality of the tested materials, among which the variation coefficient of soluble sugar content (SS) was the largest, followed by carotenoid content (Car) and chlorophyll content (Chl). Sixteen excellent wild A. eriantha germplasms were selected by principal component analysis. Genetic diversity analysis of SSR markers showed that the number of alleles detected per pair of primers was 3˜13, with an average of 5.6 alleles and 2.83 effective alleles, the Shannon 's information index was 1.12, and the Ne’s gene diversity index was 0.566. The population structure and linkage disequilibrium (LD) of the tested materials were analyzed by 40 pairs of SSR markers, after conditional filtration with gene frequency of 0.05, there was significant linkage disequilibrium in some of the SSR polymorphism markers. When P < 0.05, eight markers were found to be associated with five quality traits such as SS, titratable acid content (TA), Chl, dry matter (DM) and soluble solids content (SSC). While when P < 0.01, only a significant correlation was found between the marker A193 and SS. In this study, the relative stable markers associated with the inner quality of wild A. eriantha fruit were excavated, and specific allelic variations were established between phenotypes and genotypes. The results could lay a theoretical foundation for the breeding and genetic improvement of novel varieties of A. eriantha in the future.