Archesporogenesis, Megasporogenesis and Female Gametophyte Development of Seedless Grapevine Cultivars Nedelchev VI-4 and Russalka 1
Agricultural University, Viticulture Department, BG-4000 Plovdiv, Bulgaria
ROICHEV, V., 2000. Archesporogenesis, megasporogenesis and female gametophyte development of seedless grapevine cultivars Nedelchev VI-4 and Russalka 1. Bulg. J. Agric. Sci., 6: 545-552
Cytoembryological studies of the female sphere of the flowers of two seedless hybrid cultivars have been performed. It has been established that their ovule are bitegmic, crassinucelate and anatropous. Nucellus is formed normally but degenerates but degenerates after the formation of the embryo sac. The primary archespore is of the unicellar type and does not transform directly into a megasporocyte. Megasporogenesis is normal and successive and linear megaspore tetrads are formed. Female gametophyte develops by the polygonum type. Degeneration processes in the embryo sac start after the end of megasporogenesis and are non-synchronized. Double fertilization takes place in some of the ovules. Embryogenesis does not reach its final stage, therefore, no viable seeds are formed.
Key words: archesporogenesis, megasporogenesis, gametophyte, seedless grapevine cultivars, cultivar Nedelchev VI-4, cultivar Russalka 1