Abstract:

【Objective】 Stripe rust of wheat (Triticum aestivum L.), caused by Puccinia striiformis f. sp. tritici, has been considered one of the most damaging for wheat production in Northwest China, North China, and the Middle and Lower Reaches of Changjiang River wheat region in China. The objective of this study was to evaluate the resistance levels of current wheat and advanced lines to this disease in the target epidemic region. 【Method】 A total of 501 entries of wheat cultivars and advanced lines, collected from thirteen provinces of China, were evaluated for stripe rust resistance of seedlings in greenhouse with selected races (CYR32 and CYR33), and of adult plants in the field with eight mixed races at Yangling, and in fields under natural infections at Tianshui, during 2008-2009 wheat growth seasons. 【Result】 Among the 501 cultivars or advanced lines, there were only 34 (6.8%), and 110 (22.0%) entries that were resistant at seedling and adult plant stages respectively. A high frequency of cultivars and advanced lines (71.0%) showed a susceptible reaction (infection type ≥ 3 ) in the field at Tianshui in Gansu. There were significant differences in the resistance level of wheat entries among the different epidemic regions. According to the analysis of pedigree, the application of resistant sources of current wheat cultivars to stripe rust among different epidemic regions were focused on a little major effective Yr genes, such as Yr26/24, Guinong resistance lines, and some CIMMYT resistance lines. 【Conclusion】 The resistance levels of current cultivars to stripe rust were very low, and the forecast for epidemic situation of stripe rust must be enhanced in order to avoid stripe rust epidemic in large area. The available sources of rust resistance were too less in wheat breeding programs, and simultaneous utilization in different epidemic regions.

Key words: stripe rust, wheat cultivars, seedling resistance, adult plant resistance