Heterosis in Spring Canola Hybrids Grown in Northern Idaho

Abstract

Spring canola acreage has increased in the Pacific Northwest over the past 5 yr. Traditional cultivars are inbred lines, although a high proportion of newer cultivars are hybrids. This study examined the magnitude of heterosis in spring canola to determine the potential advantage of hybrid cultivars. Four inbred cultivars, with diverse geographic origins of development, were hand-pollinated in a diallel design. Performance of F1 hybrids and their respective inbred parents was evaluated under greenhouse conditions. Field trials were conducted at two locations to compare F1 hybrids and F2 progeny with inbred parents. Positive heterosis was found for yield, oil content, and oil quality, with the highest degree of heterosis observed for yield. Hybrids and F2 progeny produced higher yield than inbred parents because of increased pod number (primarily on the main raceme), larger seeds, and later maturity. However, the magnitude of heterosis observed varied between hybrids. Inbred and hybrid cultivars also were compared in the Pacific Northwest Regional Canola Variety Trials. In these trials, the most adapted hybrids had a yield advantage compared with the most productive inbred cultivars. However, average yield and oil content of hybrids were not significantly different from inbred cultivars. Inbred cultivars tended to have higher oil content and matured earlier. Introduction of hybrid canola cultivars in the Pacific Northwest region has potential to increase canola acreage and grower profit. However, choice of hybrid parents and economics of high quality hybrid seed production will be important factors in hybrid canola cultivar development and acceptance.