Author : Richard Gary Beaver
Publisher :
ISBN 13 :
Total Pages : 124 pages
Book Rating : 4.:/5 (162 download)
Book Synopsis Physiologic Specialization of Stripe Rust (Puccinia Striiformis West.) in the Pacific Northwest by : Richard Gary Beaver
Download or read book Physiologic Specialization of Stripe Rust (Puccinia Striiformis West.) in the Pacific Northwest written by Richard Gary Beaver and published by . This book was released on 1969 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The physiologic specialization of nine isolates of stripe rust (Puccinia striiformis West.) collected in the Pacific Northwest was determined. The separation of races was based on the differential susceptibility of the following wheat varieties: Cappelle Desprez, Chinese 166, Dippes Triumph, Druchamp, Etoile de Choisy, Flamingo, Gaines, Golden, Ibis, Leda, Michigan Amber, Moro, Omar, Rubis and Suwon x Omar4. Four race groups were identified on the differential wheat varieties when grown at a constant 18 C temperature; however, eight races could be identified when the temperature was lowered to 2C during the 10 hour dark period (2/18 C cycle). Race groups could be identified in the 18 C growth chamber using only five commercially grown Pacific Northwest wheat varieties (Gaines, Omar, Golden, Moro and Druchamp). Seven of the eight isolates tested under the 2/18 C temperature cycle could be identified using these same five commercial varieties. The reaction type of certain wheat variety-race combinations is changed with a change in incubation temperature from 18 C to 2/18 C. Thus, by growing differential varieties at these two temperatures and using changes in reaction type as a distinguishing factor all eight isolates could be separated into distinct races. Pre- or postinoculation growth temperatures influenced the reaction types of three of the differential wheat varieties. The reaction on Dippes Triumph became more resistant when the postinoculation incubation temperature was lowered (RT, 3 to 2). Suwon x Omar4 gave a more susceptible reaction when the temperature was lowered (RT, 1 to 2). The reaction type on Flamingo varied depending on the pre- and postinoculation incubation temperature combination. Reaction types produced on the first and second seedling leaves did not differ at either temperature. Rust prevalence on the first seedling leaves was reduced from usually 100 percent at 18 C to as low as 12.5 percent with certain race-variety combinations when incubated at the 2/18 C cycle. There was no change in prevalence on the second seedling leaves with a change in incubation temperature. The latent period was extended 6.4 days when the incubation temperature was changed from a constant 18 C to 2/18 C. There was no correlation between races of stripe rust and a change in the latent period. The more resistant varieties exhibited latent periods of 10.3 t o 14.3 days whereas the latent periods were 9.0 to 10.2 days for the more susceptible varieties. A determination of the apparent infection rate (r) of three races of stripe rust under field conditions gave significant differences on Baart and Federation spring wheats. The differences on Baart wheat were: r = 0.0953, r = 0.0552, and r = 0.0541 for races SW-2-1, SB-40 -1 and SW-7-1, respectively.
