Preserving genetic diversity in Pinus tabuliformis breeding population through core collection development

The conservation of genetic diversity is a crucial aspect of forest tree breeding programs, necessitating strategies for its safeguard. Here, the extent of genetic diversity was assessed in 260 Chinese pine (Pinus tabuliformis Carr.) germplasm samples from five provenances using 24 SSR markers. We systematically compared various methods for constructing a core collection aimed at conserving genetic diversity and the results revealed substantial genetic diversity within this germplasm collection. Extensive gene exchange was observed among four of the sampled five provenances which resulted in forming two genetically distinctive groups. To construct the core collection, six different sampling strategies (PowerCore, Power marker_allele number, Power marker_gene entropy, Power marker_gene diversity, Corehunter, and genetic distance-based) and five different sampling sizes (ranging from 10 to 30%) were employed. Comparative analysis of genetic diversity parameters was conducted across the identified 26 subsets, utilizing the PowerCore strategy as the primary approach for capturing all allelic variation present in the core collection, which consisted of only 61 individuals. A supplementary collection of 20 individuals with high genetic variation was identified to provide a final core collection of 81 individuals, representing 31.2% of the initial collection. The constructed core collection effectively captured the genetic diversity present in the initial collection and serves as a valuable resource for preserving genetic richness within the breeding population.