S19 - Session P6 - Rabbiteye blueberry breeding lines with self-compatibility and parthenocarpy characters

Authors: Hao-Cheng Wang, Masafumi Omori, Kuo-Tan Li *

Rabbiteye blueberry ( Vaccinium virgatum Aiton) cultivars are generally considered self-incompatible and require cross pollination for acceptable berry set. However, some breeding lines in the National Taiwan University blueberry breeding program produced satisfactory berry set and berry size under the absence of pollen donors. To validate the possibility of self-compatibility or parthenocarpy in rabbiteye blueberries, pollen morphology, pollen germination and embryonic development of 'NTU025', a candidate breeding line, and 'Climax', a commercial cultivar, were investigated after self- or cross- pollinated with 'Powderbule'. Both cultivar/line produced viable tetrad pollen grains and normal embryo sacs. Pollen tubes reaching ovules were observed in 'NTU025' after 48 h of self-pollination, but fusion of egg cells and sperm cells was not observed in either self- or cross- pollinated 'NTU025' or 'Climax'. Zygotes were formed in cross-pollinated 'Climax' and self-pollinated 'NTU025' after 72 h of pollination but not in self-pollinated 'Climax' or cross-pollinated 'NTU025'. The results confirmed self-compatibility in 'NTU025'. With previous report on the normal berry set with very few seeds in mature 'NTU025' berries, this results also suggested that NTU025 might be capable of producing seedless berry through stenospermocarpy.