1a. Objectives (from AD-416)
Evaluate the reaction of advanced barley breeding lines from various public and private breeding programs to established races of barley stripe rust (Puccinia striiformis f.sp. hordei) endemic in the Central Valley of California.
1b. Approach (from AD-416)
Barley breeders will submit their advanced lines to UCDavis researchers, who will plant the accessions in the Davis, California area or other Central Valley locations where a natural epidemic of barley stripe rust can be expected. Data collected will be returned to the participating breeders and ARS distribution to interested parties. Documents SCA with UC Davis.
3. Progress Report
The 2009-2010 wheat stripe rust nursery included 962 entries were included from 6 different cooperators. This nursery includes stripe rust differentials, released winter and spring cultivars. The nursery was planted January 1, 2010 (late, due to rain). The highly susceptible wheat cultivar, D6301 was planted around the nursery two weeks before January 1, 2010 to provide stripe rust inoculums for the experiment. The barley stripe rust nursery had 86 entries from two cooperators. The number of entries and cooperators decreased significantly compared to the previous years. The susceptible barley cultivar, Max was used as spreader row. The weather for stripe rust development was conducive but different from last year. The temperate during the month of May was unusually cooler allowing continuous development of stripe rust. The first stripe rust observation was made in early April before heading on April 18. The second evaluation was performed on May 7 when most of the accessions had headed. The third evaluation was performed on May 28. During the first scoring time, the susceptible check wheat variety, D6301 was susceptible with severity ranging from 10 to 100%, infection type ranging from 6 to 9 indicating the non-uniform infection and disease development at the time. However, during the second scoring, almost all rows of D6301 had reached severity of 100% with the highest infection types (8/9). In contrast to D6301, the susceptible barley check variety, Max was not infected at the time of first scoring May 20, 2010. Stripe rust started to infect barley after May 20 reaching severities of 20% to 80% on the variety Max. Generally, the disease pressure was sufficient to discriminate resistant from susceptible entries. To further understand the type of race we had in the past season, we have collected multiple yellow rust infected barley and wheat samples from Davis and other part of California and sent them to ARS at Pullman, WA for race analysis. Monitoring of activities in this agreement were accomplished by telephone and e-mail.