Hybrid HEAR cultivars

MSL GMS and ogu INRA CMS pollination control systems which can be used to produce commercial quantities of hybrid HEAR seed are being used to produce hybrid HEAR cultivars (Eriedt and Snowdon, 2009 McVetty et al., 2009). The winter HEAR cultivars currently available are MSL hybrid HEAR types, which exploit the natural heterosis known to occur in B. napus (Brandle and McVetty, 1990). Spring hybrid HEAR cultivars will also exploit the heterosis for seed yield available in HEAR cultivars/lines (Cuthbert et al., 2009). Seed yield increases have been accompanied by simultaneous improvements in adaptation, disease resistance and seed quality for both spring and winter habit HEAR cultivars, and herbicide tolerance for spring habit HEAR cultivars (McVetty et al., 2009). Breeding for local adaptation in spring habit HEAR has focused on early maturity in Canada, while that in winter habit HEAR has focused on winter hardiness (McVetty et al., 2(X)9 Eriedt and Snowdon, 2009). 

Breeding for improved seed yield is the main breeding objective for HEAR cultivar development programs. Eor B. napus HEAR cultivars, this has involved, successively, selection within OPP landraces, crosses of OPPs and pedigree selection of derived families and hybrids (McVetty et al., 2009). 

Semyk and Stefansson, 1982 Grant and Beversdorf, 1985 Brandle and McVetty, 1990) created significant interest in the development of hybrid canola cultivars. The report of significant heterosis for seed yield in HEAR hybrids (Cuthbert et al 2009) created similar interest. 

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