Reaction of wheat varieties to composites of races of bunt occurring in the Pacific Northwest

A total of 250 wheat varieties, including common, club, durum, emmer, poulard, Polish, and wheat X rye, were tested in 1934 at Pendleton, Ore., for resistance to a local and a Northwest composite of bunt collections differing distinctly in pathogenicity. Hussar X Hohenheimer selection (C. I. 10069-1) was the most resistant variety in these trials. Oro, Yogo, Ashkof, and Ridit were the most resistant varieties among the hard red winter wheats grown commercially in the United States. Several other varieties were highly resistant to the local composite. The infection in Minturki was 2.1% with the local composite and 61.3% with the Northwest composite. Ruby and Gamet proved most resistant of the commercial varieties of hard red spring and Berkeley Rock and Odessa of the soft red winter varieties. None of the commercial varieties of white wheat was highly resistant but Quality, White Odessa, and Axminster were the least susceptible. Albit and Hymar were the only commercial clubwheats not highly susceptible to all bunt collections. Golden Ball and Marouani showed more resistance than the other durum varieties. Vernal (emmer) appeared slightly resistant, but Alaska (poulard) and White Polish (Polish) were highly susceptible. The hard red winter and durum wheats were more resistant to bunt than the other classes of wheat, although resistant varieties created exceptions within each class. The greatest number of highly resistant varieties was found in the hard red winter and soft red winter groups. Unseasonably warm spring temperatures stimulated a second growth of tillers in the durum wheats. Most of the late tillers produced bunted heads, although the heads on early tillers were free from disease. The tendency for late tillers to be bunted also was observed in other moderately resistant wheats.