Possibilities of using haloidy technique in carrot ( Daucus carota L.) breeding

The carrot (Daucus carota L.), one of the most valuable members of the Apiaceace family and they are an important food source and economically important vegetable species. Carrot cultivation is carried out entirely from hybrid varieties. Development of F1 hybrid varieties by using pure lines is difficult because it is time-consuming by using classical selfing methods. Present study aims to use androgenesis methods in five different carrot genotypes to increase haploid plant production by using two different regeneration media. To ensure the healthy development of obtained embryos putrescine, one of the polyamines known to have a positive effect on embryogenesis, was added to one of these mediums. Studies clearly showed that there was no embryo formation in microspore culture of 5 carrot genotypes. It has been observed that the addition of putrescine to the regeneration medium in another medium combination used in the present study had a positive effect on the androgenesis response and promoted androgenesis. In this study, the highest embryo response was obtained from the donor plants of the TTS-2 genotypes with 24.13% in the HAR-2 medium, and the highest plant response was obtained from the TTS-1 genotype with 17.49% in the HAR-2 medium. Leaf samples taken from 5 genotypes used as donors in the study were analyzed with 48 SSR markers and compared with flow cytometry analysis. It was seen that the plants that belong to the TTS-1 genotype were haploid (n) in structure. In addition, the band profiles examined in the results of the SSR marker analysis were homozygous, while the plants belonging to the TTS-2, TTS-3, TTS-4, and TTS-5 genotypes were diploid (2n) and, the band profiles showed homozygous expansion in SSR marker analysis. As a result, it was understood that it was spontaneous double haploid formation. The results of this thesis study will make it possible to increase the haploid plant production in carrots by using androgenesis methods and the use of the obtained double haploid plants as pure lines in breeding studies will contribute to the breeders.