Evaluation of Self-fertility among Chestnut Varieties on Shading Treatment of the Flower and Genetic Analysis of the SSR Loci in Self-pollinated Seedlings

It has been reported that the self-sterility of the chestnut is incomplete because it exhibits weak self-fertility. However, the self-fertility rate has not been clarified among genotypes in the chestnut. In this report, we evaluated the self-fertility among chestnut varieties by means of shading treatment of the flower, and inspected self-fertility of the self-pollinated seedlings by genetic analysis of SSR loci. In 24 out of 51 genotypes, approximately 47%, various types of self-fertility were observed. Thirteen self-pollinated seedlings and their maternal parents were inspected by SSR analysis, and eight individuals derived from ‘Ibuki’, ‘Oomine’, and ‘Toyotamawase’ were confirmed to have the self-pollinated genotype. Surprisingly, ‘Toyotamawase’, one of the varieties, showed the highest rate of bur set (62.5%) and seed set (33.3%), and all their individuals were confirmed to have the self-pollinated genotype. The other five individuals derived from three varieties were also confirmed to have the cross-pollinated genotype. These results suggested that the chestnut has complete self-sterility, but some genotypes have weak self-fertility. Then, ‘Toyotamawase’ has the strongest self-fertility among the genotypes in this experiment.