Wheat Stripe Rust Epidemics and Races of Puccinia striiformis f. sp. tritici in the United States in 2000

Abstract

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is most destructive in the western United States and has become increasingly important in the south-central states. The disease has been monitored by collaborators through field surveys and in disease nurseries throughout the United States. In the year 2000, stripe rust occurred in more than 20 states throughout the country, which was the most widespread occurrence in recorded history. Although fungicide applications in many states reduced yield losses, the disease caused multimillion dollar losses in the United States, especially in Arkansas and California. One of the prevalent cultivars, RSI 5, had a yield loss of about 50% in the Sacramento-San Joaquin Delta region of California. In the Pacific Northwest, wheat losses due to stripe rust were minimal because cultivars with durable resistance were widely grown and the weather in May 2000 was not favorable for the disease. To identify races of the pathogen, stripe rust collections from 20 states across the United States were analyzed on 20 wheat differential cultivars, including Clement (Yr9, YrCle), Compair (Yr8, Yr19), and the Yr8 and Yr9 near-isogenic lines. In 2000, 21 previously identified races and 21 new races were identified. Of the 21 new races, 8 were pathotypes with combinations of virulences previously known to exist in the United States, and 13 had virulences to one or more of the lines Yr8, Yr9, Clement, or Compair. This is the first report of virulence to Yr8 and Yr9 in the United States. Most of the new races were also virulent on Express. Races that are virulent on Express have been identified in California since 1998. The races virulent on Yr8, Yr9, and Express were widely distributed in California and states east of the Rocky Mountains in 2000. The epidemic in 2000 demonstrates that increased efforts to breed for stripe rust resistance are needed in California, the south-central states, and some other states in the Great Plains. Diversification of resistance genes and use of durable resistance should prevent large-scale and severe epidemics.

Evaluation of Different Wheat Genotypes Reaction to Stripe Rust (Puccinia striiformis f.sp. tritici) under Field Conditions in Ardabil Province

“…Results of our study and the differences in the reaction of genotypes to yellow rust disease are in agreement with those of previous studies (McIntosh, [20] [22]; Herrera-Fossel et al [23]; Bux et al [13]; Shahin and Abu El-Naga, [19]). Different researchers studied the reaction of different wheat varieties to stripe rust disease in different countries [11,12,18,24]. Like in our study, the results of their study also showed that different varieties showed variable reactions to the disease and they ranked from immune to highly susceptible.…”

“…Resistance to fungicides is also another main disadvantage in using the fungicides for controlling this disease [9]. Using the resistant cultivars is the most important controlling approach in increasing the wheat yield [6,[11][12][13]. However, growing resistant cultivars is the most efficient, economical, and environmentally friendly approach to control the disease [6,12].…”

“…Using the resistant cultivars is the most important controlling approach in increasing the wheat yield [6,[11][12][13]. However, growing resistant cultivars is the most efficient, economical, and environmentally friendly approach to control the disease [6,12]. Two types of resistance have been identified in several cereal-rust pathosystems: hypersensitive or qualitative (race-specific) and quantitative (race nonspecific) resistance.…”

Review Article: High-Temperature Adult-Plant Resistance, Key for Sustainable Control of Stripe Rust

“…tritici that has been identified so far in the US [2,12,24,25]. Plus its good plant type, we have, therefore, been using it in the greenhouse to increase urediniospores of stripe rust samples collected from various regions [25,26]. early data may indicate HTAP resistance.…”

Resistance of Tangmai 4 wheat to powdery mildew, stem rust, leaf rust, and stripe rust and its chromosome composition

“…These races were selected for their virulence on most of the resistance genes that are used in wheat cultivar development. The method described by Chen et al (2002) was followed to test the cultivars with individual stripe rust races. About 20 seeds of Tangmai 4 or the susceptible check Nugaines were planted in 7.5 × 7.5 cm square pots filled with a mixture of peat, perlite, sand, commercial soil mix, and vermiculite at a ratio of 6:2:3:3:4, plus 14-14-14 Osmocote (Sierra Chemical Co., Sparks, NV) at a rate of 3.3 g L -1 .…”