The investigation of pellicle peelability on Japanese chestnut cultivar of 'Yakko' (Castanea crenata Sieb. et Zucc.)

摘要

Japanese chestnuts (Castanea crenata Sieb. et Zucc.) generally have difficult-peeling pellicles even after heating, making easy-peeling pellicle (EPP) an important breeding target. Recently, EPP cultivars 'Porotan' and `Porosuke' were released by a government-funded breeding program. However, very few genotypes carry the major recessive gene responsible for the EPP trait, resulting in inbreeding within a narrow gene pool. To discover other genetic materials having the potential for EPP breeding, we evaluated the pellicle peelability of 59 accessions (51 Japanese local cultivars and 8 wild individuals) by using the high-temperature oil peeling method. We discovered that 'Yakko' had an exceptionally high pellicle peelability score (87%), close to that of 'Porotan' (94%). The results of segregation ratio analysis of pellicle peelability and genotype prediction by simple sequence repeat (SSR) markers among F-1 seedlings suggested that the EPP alleles of 'Porotan' and 'Yakko' are at the same locus. However, a haplotype structure analysis of the EPP genome region with SSR markers revealed that both haplotypes of 'Yakko' differed from those of 'Porotan', suggesting that the EPP gene of 'Yakko' had a different origin from that of 'Porotan' or was inherited from a common ancestor many generations ago.