Fertility and Other Characteristics of F1 and Backcross1 Progeny from an Intersectional Blueberry Cross [(highbush cultivar x Vaccinium arboreum) x highbush cultivar]

Fertility and morphological traits were studied in the F-1 and BC1 generations of intersectional crosses between tetraploid highbush blueberry cultivars (Vaccinium section Cyanococcus) and colchicine-induced tetraploid V. arboreum (Vaccinium section Batodendron). The goal of the introgression project was to combine desirable plant characteristics from V. arboreum with the large fruit and high fruit quality of highbush cultivars. Highbush x V. arboreum crosses were hard to make, but large numbers of BC1 seedlings were easily obtained using the most fertile F-1 plants as parents in backcrosses to highbush. Anther awns, a character from V. arboreum, were present in all F-1 seedlings, but fruit sclerids, another V. arboreum trait, were absent in most seedlings. Berry size in the BC1 generation was twice as large as in the F-1 generation and was twice as large in the F-1 as in V. arboreum. The BC1 generation was extremely variable in vigor and berry quality. Although berries of most BC1 plants were smaller, darker, and less desirable in texture and flavor than highbush berries, the high fertility of BC1 plants and the high variability among plants indicate that useful clones could be selected or developed by further breeding.