|DRUMMOND, FRANCIS - University Of Maine|
Submitted to: International Journal of Fruit Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/6/2010
Publication Date: 1/1/2012
Citation: Bell, D.J., Rowland, L.J., Drummond, F.A. 2012. Does pollen "neighborhood" affect yield in lowbush blueberry (Vaccinium angustifolium Ait.)? International Journal of Fruit Science. 12:65-74.
Interpretive Summary: About 1/3 of commercial blueberry production is from managed, wild stands of lowbush blueberry. Lowbush blueberry grows in a patchwork of individual plants referred to as clones. Variation among clones is very high with adjacent clones showing as much as 12-15 fold differences in berry yield. The focus of this research is to identify genetic factors responsible for these yield differences. We tested whether pollination occurring between individual blueberry plants that are too closely related may result in low yields due to inbreeding. In this study, molecular markers were used to evaluate how closely related individual plants were to one another. Then we carried out controlled pollinations of plants to determine if the closeness of this relationship affects yield. Surprisingly, it was found that genetic relationship does not have a significant effect on yield. However, it was found that yield could be improved in some low yielding clones by pollinating them with clones that were located distant in the field. This information will be used by scientists to make recommendations to growers on ways to improve yields in lowbush blueberry.
Technical Abstract: Proximally growing individuals of wild, lowbush blueberry (Vaccinium angustifolium Ait.) vary widely in yield despite being grown under conditions in which environmental heterogeneity is minimized by cultivation practices. We recently established that the relative self-fertility of the bearing plant is a significant predictor of its outcross yield. Further, although the species has historically been characterized as largely self-infertile, we, and others, have documented large variation in this trait among individuals within fields, and thus relative self-fertility stands as a partial explanation of yield variation, in addition to other genetic factors such as significant general and specific combining abilities. Here we extend our scope by experimentally addressing whether pollen neighborhood affects yield. Lowbush blueberry is not sown, rather individuals have colonized fields by natural processes. Commercial fields of lowbush are generally pollinated by rented honey bees, which tend to pollinate nearby flowers. Our hypothesis is that clones may have become situated in differentially suitable pollen environments, at least partly explaining yield differences. We identified two high and two low natural yielders from each of two managed fields and collected pollen mixes from five donors surrounding each (n=8). Under field conditions, each recipient received four pollination treatments including its own neighborhood and the other three donor neighborhoods within the same field. Results showed that one of the low producers in each field had significantly higher yields when pollinated by any but their own neighborhood, thus substantiating our hypothesis that pollen neighborhood has an effect on yield.