Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 1999
Publication Date: N/A
Interpretive Summary: The soybean cyst nematode is the most important pathogen of soybean in the United States. In southeastern Missouri, North Carolina, and Tennessee, races 2 and 5 of the nematode are becoming increasingly common. The Hartwig cultivar is the best source of resistance to these races when developing new cultivars. Screening offspring of crosses involving Hartwig gwith race 2 alone identifies plants with resistance to both races 2 and 5. Thus, screening with race 2 alone is more efficient than screening with both races of the nematode in development of new cultivars with resistance to this important pest. This information will enable plant breeders to develop new cultivars more efficiently.
Technical Abstract: Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is a major pest of soybean [Glycine max (L.)] in the USA and has many races. The use of SCN resistant cultivars effects changes in the ability of H. glycines field populations to parasitize these cultivars. Progenies of crosses involving Hartwig soybean were tested for resistance to either SCN race 2 or 5 in the eF2 generation and for resistance to both races in the F2:3 generation. Al F2:3 progenies resistant to race 2 were also resistant to race 5. Only 64% of F2:3 progenies resistant to race 5 were also resistant to race 2. These results indicate that it is more efficient to screen for race 2 resistance alone than to screen for resistance to either race 5 or both races when resistance to both races is sought from crosses involving Hartwig. .