Identification and genetic diversity analysis of specific walnut F1 progeny based on SSR molecular markers: taking heart-shaped walnuts and Jinghong 1 as examples

To gain a deeper understanding of the genetic diversity and authenticity of natural pollinated F1 progeny populations of specific walnuts (heart-shaped walnuts and Jinghong 1), as well as the genetic relationship between F1 offspring and their maternal parent. 32 heart-shaped walnut F1 offspring, 45 Jinghong 1 F1 offspring, and their maternal parent were selected as materials, and 14 pairs of SSR markers were used for genetic diversity and parent-child relationship analysis. The results showed that Jr05, Jr11, Jr29, Jr44, Jr45, Jr52, Jr53, Jr55, and Jr56 could be used as SSR markers for the identification of hybrid offspring in heart-shaped walnuts. Jr35, Jr40, Jr45, Jr50, Jr52, and Jr53 could be used as SSR markers for the identification of hybrid offspring of Jinghong 1. XX21 had the closer genetic relationship with heart-shaped walnuts, and HR20 had the closer genetic relationship with Jinghong 1. Besides, the classification results of F1 offspring based on UPGMA clustering and STRUCTURE were different. This study not only laid the foundation for parental identification of specific walnut F1 progeny, but also provided theoretical reference for fixing hybrid advantages, germplasm innovation, and new variety breeding.