Interspecific hybridization as an inducing factor of ogura-type cms in Brassica plants

Abstract

In our recent study the one male sterile plant BKBu3 has been found in BC1-progeny from interspecific crossing of tetraploid fertile B. oleracea and allotetraploid fertile B. carinata lines. The flowers of male sterile plant had reduced, necrotic anthers, and no fertile pollen was observed. However, other organs of flowers were phenotypically and functionally normal. No segregation in sterility/fertility morphology of the BC2 progeny plants indicated a cytoplasmic mode of male sterility inheritance. To determine the type of the found cytoplasmic male sterility (CMS), the authors conducted a molecular-genetic analysis using orf138-specific primers. The PCR analysis indicated that the found cytoplasmic male sterility is of an Ogura-type. Screening the fertile lines of B. carinata, diploid B. oleracea, and fertile plants of BC2 progeny of interspecific cross and a partially fertile B. oleracea-carinata hybrid revealed ~600 bp amplicons that are not matched to the orf138-marker fragment. It was suggested that the presence of ~600 bp amplicons could be an outcome of chimeric cytoplasm of male fertile plants, and it could also be a reason why CMS plants are formed in a progeny of interspecific hybrids.