Interspecific hybridisation of cytoplasmic male-sterile rapeseed with Ogura cytoplasm and Brassica rapa var. pekinensis as a method to obtain male-sterile Chinese cabbage inbred lines

Abstract

During 2011–2014, three self-compatible Chinese cabbage inbred lines (Brassica rapa, genome AA 2n = 20) were sexually hybridised with cytoplasmic male-sterile (CMS Ogu-INRA) and fertile lines of rapeseed (Brassica napus var. oleifera, genome AACC 2n = 38). Interspecific F1 hybrids and their consecutive back-crosses (BCs) toward B. rapa were obtained, and their morphological and commercial characteristics, as well as their ability for generative propagation, were analysed. Cytometric and morphological analyses confirmed the interspecific character of the F1 hybrids in comparison with B. napus and B. rapa parental lines. All interspecific F1 hybrids had intermediate morphological characteristics typical of both parental components in the generative and vegetative stages. The F1 hybrids of CMS B. napus × B. rapa were sterile, as were those of fertile B. napus × B. rapa. Good seed productivity from CMS B. napus × B. rapa and consecutive back-cross 1 (BC1)–BC3 generations with Chinese cabbage as the recurrent parent was obtained. Plants of the BC1 generation of CMS B. napus × B. rapa were sterile and had highly diversified morphological characteristics, both in the vegetative and generative phases. The BC3 generation of CMS B. rapa was also sterile and more uniform than BC1, with good vigour and most of the typical Chinese cabbage agronomic traits. As a result, a collection of Chinese cabbage genotypes having the CMS trait, which is valuable for the breeding of commercial F1 hybrids, was obtained for the first time in Poland.