IN-VITRO GERMINATION OF STENOSPERMIC SEEDS FROM RECIPROCAL CROSSES (VITIS-VINIFERA L.) APPLYING DIFFERENT TECHNIQUES

The frequency of germination of stenospermic seeds cultured in vitro i s analysed for two crosses of seedless varieties (Vitis vinifera I,.) and their reciprocals. In the case of Superior x Dawn (SxD) the freque ncy of germination was not different to that of Superior x Ruby (SxR). Results of the reciprocal cross (SxD, DxS) show significantly better results with SxD. In the reciprocal cross SxR and RxS direct germinati on (DG) is compared with embryo excision (EE) and seed coat rupture (S CR). The majority of embryos of varieties with very soft seed coats, e .g. Superior, germinate directly: 18.8 % in DG, 18.4 % in EE and 23.2 % in SCR. Germination of varieties with harder seed coats (Ruby) could be mechanically affected: 17.6 % in DG, 62.4 % in EE and 58.8 % in SC R. There is no significant difference between EE and SCR. The results of SCR confirm that there is no inhibition of in vitro germination by chemical inhibitors in the seed tissues. The results of CR and EE for SxR and RxS show a greater capacity of Ruby to generate viable embryos .