Inbreeding and founder cultivars contributions in low chill requirement peaches and nectarines

Abstract

The pedigree analysis from genealogical data can estimate the inbreeding from identity-by-descent, being a powerful tool for germplasm characterization. The aim of this study was to evaluate the genetic diversity of peach and nectarine cultivars from the Agronomic Institute Prunus germplasm. This assessment was based on inbreeding and coancestry coefficients, considering two cases according to the origin of pollen donor in open pollinations: case I as self-pollinated, and case II as outcrossing. This study provided information regarding the founder cultivars. The historical investigation of the genealogy of 84 cultivars returned up to eight generations. Thirty-one founder cultivars were identified. The inbreeding coefficient of 40 (case I) and 14 (case II) for the cultivars were higher than expected, evidencing some degree of inbreeding. However, the averages for the coancestry coefficients were low (case I: 0.144; case II: 0.087), indicating genetic variability among the cultivars, which may be used in breeding programs.