Ovule and seed culture from early ripening seedless and seeded grape cultivars

The development of seedless Vitis vinifera cultivars is a major goal of the grape breeding program at the Volcani Center, A.R.O. Considerable interest is also shown in the development of both seeded and seedless early ripening cultivars. In pursuing these aims, certain difficulties arise. Only a relatively small percentage of progeny from crosses between seeded and seedless cultivars yields stenospermocarpic fruit without noticeable seed traces (between 6.5 to 9.5070 in our breeding program). There is scarce genetic knowledge concerning the inheritance of the character for seedlessness. It seems that seedlessness is controlled by recessive genes (5, 13) although the claim of dominant control has also been raised (8, 12), this does not seem to be bome out by the data obtained so far by uso Raising selfed progeny or progeny from crosses. between stenospermocarpic cultivars might therefore yield a higher proportion of seedless progeny. Nitsch et al. (7) and later Barritt (2) reported that embryo and/or endosperm breakdown occur about 3 weeks after bloom, in stemospermocarpic fruito Embryos and plants have been cultured from a grape hybrid with a large abortive ovule by Cain (3) and in-ovulo embryo culture of Thompson Seedless has been recently described by Emershad and Ramming (4). Our work with 3 leading cultivars of stenospermocarpic Vitis vinifera in 1982 and 1983 has been reported recently (II). Main findings and work performed during 1984 will also be reported here, as well as recent results obtained with the culturing of inmature embryos from seeds of early ripening seeded Vitis vinifera cultivars.