Pollination and mating dynamics unveiled by orchard-wide pedigree reconstruction in Acacia crassicarpa

Abstract

Successfully executing breeding or conservation strategies for forest species relies on a comprehensive understanding of their reproductive systems. In this study, we investigated the mating dynamics of an Acacia crassicarpa seed orchard during a mating season. Our analysis involved genotyping 84,315 seedlings using forty-two single nucleotide polymorphism markers (SNP) to reveal parentage in open-pollinated progeny arrays. Our findings indicate that 67.8% of the seedlings originated from within orchard pollinations, 12.8% from a known male parent in a neighboring orchard, and 19.4% exhibited unknown pollen contamination. Each open-pollinated progeny array displayed a high level of male diversity, with an average of 50 out of 58 known male parents. Interestingly, on average, the dominant male contributed 23% of the progeny. Furthermore, we observed significant variation in reproductive success among genotypes, with 50% of parents responsible for 84% of the seed production. Spatial analysis revealed that pollination declined rapidly with distance, highlighting the importance of understanding pollen dispersion patterns. By informing enhanced breeding strategies and contributing to more effective conservation tactics, our study contributes to the sustainable management of Acacia crassicarpa populations and holds significant value for forest researchers working with insect-pollinated tree species.