Phytopathology (1996) 86, p. S57 (Watkins et al.)

J.E. Watkins and S.S. Rutledge (1996)
Virulence of the natural leaf rust population in Nebraska during 1994 and 1995
Phytopathology 86 (11 suppl.), S57-S57
Abstract: In 1994 and 1995, 139 and 120 single uredinium isolates of Puccinia recondita, respectively, were characterized for virulence to 16 near-isogenic, single-gene differentials in a Thatcher genetic background. Field samples in both years were collected from four wheat-growing regions in Nebraska. Thirty virulence combination were identified from the 1994 isolates and 28 were identified from the 1995 isolates. Virulence phenotypes MBR-10,18; MDR-10,18; and TDR-10,18 were the most prevalent and comprised 50% of virulence phenotypes classified in 1994 and 43% of those classified in 1995. Seventeen new virulence phenotypes were identified in 1995 that were not identified in 1994. This in part was due to a greater number of isolates showing virulence to Lr21 in 1995 as compared to 1994. During both years, in all regions, virulence was high to leaf rust resistance genes Lr1, Lr3, 3ka, Lr10, Lr11, Lr18, Lr24, and Lr30. The virulence frequency was moderate to Lr2a and Lr2c and low to Lr9, Lr16, Lr17, Lr19, Lr21, and Lr26. Seventeen percent of the 1994 isolates and 28% of the 1995 isolates were virulent on 10 or more of the differentials.

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Puccinia triticina	Wheat (Triticum)	U.S.A. (mid N)