Long-term storage does not affect the genetic diversity of pedunculate oak acorns; instead, the collection process is crucial

Abstract

Pedunculate oak (Quercus robur L.) has high economic and ecological value. Unfortunately, irregular intervals of fruiting of this tree species make it sometimes necessary to store seeds as a safeguard against years of poor yields despite the related difficulties. In this study, we addressed the problem of potential changes in the gene pool richness of long-term stored acorns. Our study was conducted for two pedunculate oak seed stands in the south of Poland. Acorns from Niepołomice were stored for 53 months, whereas acorns from Kobiór were stored for 28 months. We analyzed the genetic variation of seedlings grown from acorns before and after storage. Additionally, we compared these results with the gene pools of the source forest stands and of natural regenerations from both locations. As far as we know, this is the first report about changes in the gene pools of long-term stored acorns in relation to the gene pools of their corresponding source stands and natural regenerations. We found that genetic variation was high and comparable across all study groups. We noted only slight changes in the gene pools after long-term storage, which were more pronounced in Kobiór. Our results indicated that the gene pools of acorns were not representative of their corresponding source stands. We conclude that the seeds collection has a significantly greater impact on the gene pool of future planting material than the storage itself. Therefore, there is no evidence to discourage the use of long-term stored acorns for planting purposes.