Identification of New Germplasm Resistant to Soybean Cyst Nematode in Improved Soybean Lines.

Soybean cyst nematode (SCN) is a devastating pathogen in soybean production worldwide. Development of resistant varieties is an effective way to control SCN. But the undesirable agronomic traits of most resistant germplasm make it difficult to the breeding of resistant lines. Therefore, most of the resistant genes come from elite germplasm, i.e. PI88788 and Peking, which resulted in the narrow genetic base of released resistant varieties. Identification of new resistant sources with better agronomic traits will accelerate resistant breeding greatly. From 2003 to 2012, a total of 1043 improved soybean lines were evaluated with Race 1 in greenhouse. Among these improved lines, five hundred and twenty-nine were from National Uniform Test, two hundreds and fifty-five were from the Regional Test of Improved Soybean Lines, which is organized by breeders in Huanghuai Valleys, two hundreds and fifty-seven were from uniform test of Anhui Province. Three new resistant lines were screened out with repeated evaluation among 3 years. The resistant genes in Zhongpin 03-5368 were derived from widely used SCN gremplasm, Peking, PI437654 and Huipizhi Hedou (ZDD2315). While another two resistant lines might include new genes because no known resistant line had been fund in their pedigree. The agronomic traits of the two lines were so ideal that it had been authorized to release in Hebei Province as high yield varieties. Discovery of resistant genes in the two varieties will be of great importance to the development of new resistant varieties in China.

Key word: Soybean cyst nematode, resistance, improved lines.