Investigation of the possibilities of creating fertile Solanum melongena × Solanum torvum hybrid populations in eggplant and dihaploidization through androgenesis in eggplant rootstocks

In this study, hybrid individuals were obtained from 33 of 35 S. melongena × S. torvum hybrid combinations and 18.8% pollen viability and 9.2% germination rates were observed in biennial plants of one combination. No success was achieved in selfing and backcrosses experiments performed using these individuals. In order to obtain tetraploid S. melongena × S. torvum hybrids, colchicine was applied in seven combinations in in vitro and in vivo and only five tetraploid individuals were obtained from in vitro applications. In the tetraploid individuals, percentages of the pollen viability and germination ranged from 9.60% to 31.60%, and 3.4% to 15.60%, respectively. While embryos and plants could not be observed from anther and microspore culture studies using tetraploid individuals, pro-embryos including 3 and 5 nuclei were observed in microspore culture nutrient medium named number 2 on the 8th day in Sm18 × 23 tetraploid hybrid combination. While no hybrid individual can be obtained in bridge hybrid studies using S. americanum; in S. torvum × S aethiopicum hybrids, in which S. torvum was used as female parent, no fruit set was observed. In six combinations of S. aethiopicum, in which S. torvum was used as a male parent, seeds degenerated. In just one combination, seeds and healthy plants assessed completely similar to the female parent were obtained. Hybrid individuals were obtained from diallel S. melongena × S. aethiopicum combinations. In crossing studies in which these hybrids and S. torvum were used as the female and male parent respectively, triple hybrids carrying the genome of S. torvum were found as well as dual hybrids non-carrying. The viability and germination performance of all triple hybrids obtained were not enough. In the anther culture study carried out with eggplant rootstocks, while somatic cell-derived callus development was observed in almost all of the anthers cultured, embryo formation was not detected. While no seed was obtained from AGR 703.1 F1 rootstock, seeds were observed in Köksal F1 rootstock. A total of 22 morphological features were evaluated in the morphological characterization study of F2 and F3 individuals carried out using these seeds. Key words: eggplant, interspecific crossing, bridge hybrid, chromosome doubling, androgenesis