CYTOGENETICAL STUDIES OF 3 VITIS SPECIES

The aim of this study was to determine the genomic relationship betwee n Vitis vinifera, V. rotundifolia and V. rupestris. The hybrid between V. vinifera and V. rotundifolia (RT88-2) was almost sterile, whereas the hybrid between V. vinifera and V. rupestris (RP88-14) was fertile. A low percentage (0.52%) of the F1 hybrid (RT88-2) seed germinated, p rovided that V. vinifera was the seed parent. The result of this one w ay ability to cross could possibly be attributed to the incompatibilit y between the cytoplasm of V. rotundifolia and the chromosomes of V. v inifera. The F1 hybrid RT88-2 had 39 chromosomes of which 19 were deri ved from V. vinifera and 20 from V. rotundifolia. The homology differs between the genomes of V. vinifera and V. rotundifolia. The sterility of the F1 hybrid was chromosomal and was reflected in the abnormal me iosis and lower chiasma frequency. The F1 hybrid RP88-14 had normal me iosis and a chiasma, frequency similar to that of the parents. This co uld be attributed to the fact that the parents (V. vinifera and V. rup estris) have the same chromosome number and are closely related.