Assessment of agronomic performance and heterosis for agronomic traits in hybrid high erucic acid rapeseed (HEAR)

Twelve genetically diverse and geographically distinct high erucic acid rapeseed (HEAR) Brassica napus L. cultivars/lines were selected and crossed by hand emasculation in a topcross design to produce 45 F1 hybrid combinations. Seven of the twelve parents were HEAR cultivars/lines developed by the University of Manitoba (UM) and the remaining five parents were proprietary European (EU) HEAR cultivars/lines. Adequate seed was produced to evaluate the hybrids and parents in replicated yield trials in six environments in Manitoba during 2004 and 2005. Vigor, days to first flower, days to maturity, lodging, plant height, and seed yield were assessed. The hybrids were generally more vigorous, taller and more lodging resistant than their parents with similar days to first flower and days to maturity as their earlier parents. The best hybrids in this study displayed high parent heterosis for seed yield of up to 143% and commercial heterosis for seed yield of up to 99%. These hybrids were from the most genetically diverse UM × EU crosses. HEAR hybrids appear very promising approach to increase seed yields in this crop. Key words: Brassica napus L., HEAR, heterosis, hybrids, genetic diversity