Abstract
GA-induced seedless berries containing immature abnormal tissues in the internal parts of matured berries, were found in Muscat Bailey A grapes. The development of the abnormal tissues was studied and a couple of factors affecting their formation are discussed.
1. The abnormal tissues developed inside the flesh were of three types; globular, spindle and cylindrical in shape. While the flesh was mature, the abnormal tissue was immature and covered with green pericarp-like tissue. Of these three types, globular and spindle ones were mainly produced in GA-treated berries, and cylindrical one mostly appeared in non-treated berries.
2. The abnormal berries were produced more frequently by GA-treatment, and vigorous shoots and perfect hermaphrodites were predominant for their formation. The formation of abnormal berries was significantly correlated with the formation of GA-induced seedless ones at a 1% level. The abnormal berries were formed to a greater extent, when GA was applied 12 days before anthesis, than the applications at 22, 17, 7 and 0 days. The abnormal tissues were also well found in berries with three locules.
3. The symptoms that precede abnormal berry development, were observed early in flowerets at anthesis. The abnormal tissues were originated from a basal portion of core as a protuberant tissue and frequently in a larger ovary. Some abnormal tissues formed corolla, anther and female organ on the basal core at anthesis and developed into flowers during green stage, and finally matured to fruits that obtained seeds at ripening stage.
