Asymmetric Reciprocal Crossing Behavior of an Andean Blueberry ( V. meridionale ) × Lingonberry ( V. vitis-idaea ) Hybrid.

The fertility and crossing behavior of a tetraploid hybrid of 4x Andean blueberry ( V. meridionale ) and lingonberry ( V. vitis-idaea ) was evaluated through a series of crosses. Crosses of the hybrid with highbush blueberry produced divergent results. When used as a female with V. corymbosum males, virtually all offspring were hexaploid, most likely arising from 2 n = 4 x = 48 female gametes, and 1 n = 2 x = 24 male gametes. However, when used as a male, tetraploid hybrids were produced, resulting from 1 n = 2 x = 24 gametes from each parent. To further examine this crossing behavior, the 4 x V. meridionale - V. vitis-idaea interspecific hybrid was pollinated with 6 x V. virgatum (rabbiteye blueberry). Analogous to the previous crosses, 7 x hybrids were produced from the joining of 2 n = 4 x = 48 female gametes with 1 n = 3 x = 36 male gametes. Such reciprocal crossing asymmetry is unprecedented. The ability to produce both 6x and 4x offspring from the same V. corymbosum parents allows the potential of bridging a V. meridionale hybrid genotype to both the tetraploid ( V. corymbosum ) and hexaploid ( V. virgatum ) commercial crop levels.