Sterility and variation resulting from the transfer of polima cytoplasmic male sterility from Brassica napus into Brassica chinensis

Abstract

Male sterile combinations made from interspecific crosses between the polima CMS line of Brassica napus and varieties of B. chinensis were backcrossed to BC₃. Twenty-six selfing lines from B. chinensis were tested for their ability to either maintain complete sterility or to restore fertility in crosses with the polima male sterile line. Results show that four of these hybrids were completely male sterile and two were fertile. The sterility of the B. chinensis with polima cytoplasm was much more stable than male sterile lines with B. campestris and B. chinensis cytoplasm, which were sterile before full flowering but progressively became fertile as flowering proceeded. The results suggest that polima cytoplasm could be a suitable male sterile-inducing allocytoplasm for B. chinensis, as both maintainers and restorers are available, and could supply a reliable pollination control system for hybrid seed production in this species.