Genetics of resistance to Ustilago tritici in ‘Glenlea’ wheat (Triticum aestivum)

Abstract ‘Glenlea’ wheat (Triticum aestivum) is resistant to prevalent races of loose smut (Ustilago tritici) found on the Canadian prairies. Little is known about the genetics of this resistance. This study was undertaken to determine if ‘Glenlea’ possesses a single gene with broad resistance to multiple loose smut races representing virulence found on the Canadian prairies. ‘Glenlea’ was crossed with the susceptible cultivar ‘AC Taber’, and doubled haploid lines were produced from the resulting F, plants. Each of the 62 lines was inoculated with U. tritici races T2, T9, TIO, T15, T19, and T39. The differential segregation of lines to these races could be explained by no fewer than three major and possibly two minor genes within ‘Glenlea’. No one major gene provided complete or moderate resistance to all races representing the prominent virulence of U. tritici on the prairies (T2, T9, T10, and T39). The implications for marker development are that at least two markers would be required, one to each of th...