Forty-six years of genetic improvement in Canadian durum wheat cultivars

Abstract

The first durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] cultivar developed in Canada was Stewart 63, registered in 1963. The objective of this paper is to document genetic progress in Canadian durum cultivars since that time. The genetic potential for grain yield in the main durum production area increased by about 0.7% per year and shows no sign of tapering off. This genetic potential has been captured in commercial farm yields, which increased by 1.5% per year during the same period. Grain protein concentration tended to increase slightly over the same time period because of the requirement for minimum protein concentration for cultivar release in Canada. Based on a study of two unselected doubled haploid populations, it was estimated that genetic gain for grain yield was reduced by 8 to 15% because of the negative correlation of protein concentration with yield. Yellow pigment concentration of semolina increased during the study period, especially after the mid 1990s, when higher pigment became an important breeding target. Gluten strength has also been increased since the mid 1990s. Grain cadmium concentration was reduced by about 50% to satisfy the requirements of certain export markets. Resistance to leaf and stem rust was maintained in all cultivars released since Stewart 63. In the past 10 yr, breeding has exploited genetic variation in resistance to Fusarium head blight to produce cultivars such as Brigade and CDC Verona with intermediate levels of resistance. There appears to be remaining genetic variability for all major traits in lines currently in registration trials.