Sampling Survey and Identification of Races of Soybean Cyst Nematode (Heterodera glycines Ichinohe) in Huang-Huai Valleys

Soybean cyst nematode (SCN Heterodera glycines Ichinohe) is one of the most important nationwide soybean diseases in China. A total of 38 soil specimens or locations in the area was sampled and tested for SCN races during 2001–2003 for the inspection of race distribution in Huang-Huai Valleys. A map of race distribution was constructed according to the data from both the present study and the published reports cited. Three areas, namely, the area of southeast to Jinan in Shangdong Province; the area of northern Henan Province and its border region to south of Hebei Province; and the area of Luohe, Zhoukou of Henan Province and Fuyang of Anhui Province mainly infested with Race 1 were identified. Race 4 was predominant in Shanxi Province, Beijing and the adjacent area of Henan, Shandong, and Anhui provinces, and the delta of Huanghe River in Shandong Province. Race 2 was mainly found in Liaocheng, Dezhou of Shangdong Province and Shijiazhuang of Hebei Province, and Jiaozuo and Huojia of Henan Province. Race 7 was distributed in the west part of Jiaodong Peninsula of Shandong Province and Kaifeng, Huaxian, Wenxian of Henan Province. Race 5 was found and scattered in Hebei and Henan Province. Race 9 was found in Shangqiu of Henan Province, which was reported for the first time in China. It can be seen that Race 1 and Race 4 were the two predominant races in Huang-Huai Valleys, and that research should focus on developing resistant cultivars of these races. There might exist other races in an area with some predominant races. The race substitution in the past decade was not obviously found, therefore, the results should be meaningful to future breeding for resistance to SCN in Huang-Huai Valleys.