Heterosis in interparietal hybrids of summer turnip rape in western Canada

Abstract

Handcrossed hybrids were made between Brassica rapa L. var. oleifera cv. Tobin and 19 European and Canadian strains in order to evaluate potential for future heterosis breeding. Hybrids and parents were evaluated at one location in 1987 and two in 1988 using a six-replicate randomized complete block design with accompanying analysis of covariance utilising check rows between each of the treatments. Mid-parent heterosis of the F1 strains averaged + 18% for seed yield, −1.0% for oil content (0.4% lower actual oil), + 17% for oil yield, −0.7% for days to mature (~ 0.6 d later maturing), and + 7.0% for height. No heterosis was observed for days to flower or mean single seed weight. The best canola-quality F1 hybrid (cv. Tobin × Strain SC) yielded 21% more seed than cv. Tobin, was 0.6% lower in actual oil content and 3.1 d later maturing. The level of heterosis observed may justify the development of commercial F1 hybrids.Key words: Heterosis, hybrid, B. campestris, turnip rape