Cabbage breeding is a very complicated and long-term procedure. In Brassicas the production of hybrid seeds generally relies on self-incompatibility system that does not provide fully hybrid progeny. CMS is an easier and faster method to achieve hybrid seeds. It ensures completely hybrid progeny, because self-pollination is not possible. CMS is inherited maternally through cytoplasm. There are few sources of CMS, but the most commonly used in Brassicca breeding is the Ogura type. It was introduced from radish CMS cytoplasm. In our research we wanted to confirm the presence of the gene orf138 in our genotypes with molecular and phenotypic markers. Isolated DNAs from 20 varieties of white cabbage were checked with published PCR based markers. The amplification and sequence analysis did not reveal any significant differences among the varieties. New primer pairs aimed at amplifying regions of the orf138 gene were therefore designed and tested. We successfully amplified the region including the orf138 gene. Sequence analysis showed homology with already known sequences for CMS in radish and cabbage. The orf138 gene, responsible for CMS, was confirmed in two studied hybrid varieties: 'Liberator F1' and 'Tolerator F1'. We also isolated microspores of our genotypes to check their responsiveness to microspore embryogenesis. With observation of flower morphology we confirmed molecular results, because there was no pollen formed at the stamens.
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