Performance of inter-cultivar summer turnip rape hybrids in Saskatchewan

The agronomic performance of inter-cultivar hybrids of Brassica rapa L. was studied in crosses between four B. rapa cultivars. Six reciprocal hybrid combinations were produced by hand pollination in the greenhouse. Hybrids and their parents were tested in replicated yield tests for 3 yr. An average, over all hybrid combinations, of 13% heterosis for seed yield was observed. Heterosis for seed yield was greatest in crosses between genetically diverse cultivars, which agrees with classical theories on heterosis. There were also significant differences in yield of reciprocal F1 combinations. Seed oil content was not heterotic. The results of this study indicated that the level of heterosis of seed yield in crosses between B. rapa cultivars adapted for production in western Canada is sufficient to warrant the development of a suitable pollination control system for hybrid B. rapa production. Key words:Brassica rapa, Brassica campestris, inter-cultivar hybrids, seed yield, heterosis