Association Mapping Analysis of Morphological Characteristics in F₂ Population of Perilla (Perilla frutescens L.) Using SSR Markers

To identify SSR markers associated with both quantitative and qualitative traits in Perilla, we analyzed a total of 68 individuals from an F₂ population derived from a cross between WPC06-339 (weedy var. crispa) and WPF17-049 (weedy var. frutescens) using 40 SSR primer sets. The genetic diversity of these markers ranged from 0.464 to 0.676, with a mean value of 0.607. Correlation analysis of 13 morphological traits (4 qualitative, 9 quantitative) revealed significant positive correlations among three leaf-related traits and two inflorescence-related traits. Association analysis involving 40 SSR markers and the 13 morphological traits identified 39 significant marker–trait associations, comprising 18 SSR markers associated with 11 morphological traits. Among these SSR markers, 12 were associated with two to five quantitative or qualitative traits. Additionally, 10 SSR markers were significantly associated with three qualitative traits, while 15 SSR markers were associated with eight quantitative traits. Notably, GBPFM179, KNUPF59, and KNUPF167 were significantly associated with multiple quantitative or qualitative traits. GBPFM179 and KNUPF182 exhibited the highest R² values, of 0.38, for stem color and days to maturity, respectively. These SSR markers demonstrate the potential for use in marker-assisted selection in Perilla breeding programs aimed at enhancing leaf or seed productivity through the selection of both quantitative and qualitative traits.