Variation and Genetic Control of Seed Germination in Pinus oocarpa Trees with Different Levels of Resin Production: Implications for Conservation

Pinus oocarpa is ecologically and economically important because of its resin production; however, the effects of variation in resin production on its reproductive performance remain poorly understood. This study aimed to evaluate the variation and genetic control of seed germination in high-resin-producing, low-resin-producing, and non-resin-tapped trees. Seeds from the three tree groups were collected, germinated, and counted daily to evaluate eight germination indices. The variation, heritability, and genetic correlations of the germination traits were estimated separately for each tree group. Four of the eight germination indices were significantly lower in trees with high resin production, demonstrating the negative effect of resin production on seed germination. The distribution of variation, genetic coefficients of variation (7.68 to 68.21%), heritability estimates (0.63 to 0.75), and phenotypic correlations (−0.09 to −0.76; 0.13 to 0.94) were similar among the tree groups; however, genetic correlations (−0.12 to −0.99; 0.20 to 0.99) were stronger in high-resin-producing trees. The lower germination capacity and germination rate observed in high resin-producing trees may compromise natural regeneration. Therefore, conservation strategies should prioritize reforestation using seeds from high resin-producing trees that also exhibit high germination capacity, thereby helping maintain forest persistence and productivity.