Investigation of resistance to Heterodera glycines (scn) in soybean plant introductions (pi) 467312 and 507354

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Soybean cyst nematode (SCN) Heterodera glycines Ichinohe is the most serious pest of soybean [Glycine max (L.) Merr.] in the world. The effectiveness of breeding soybean SCN resistant cultivars is reduced by the variation of SCN population and narrow genetic basis of resistant soybean cultivars. Hence, it is important to investigate new soybean SCN resistant sources for new genes that confer resistance to SCN field populations such as HG type 1.2.7 to provide durable resistance. Soybean plant introductions PI 467312 and PI 507354, are unique, with resistance to SCN multiple HG types respectively. However, the genetic basis of SCN resistance in these PIs is not known. The objectives of this study are to investigate the inheritance of resistance to SCN HG types 0, 1.2.7, and 1.3.6.7 in PI 467312 and the SCN resistance to SCN HG types 2.5.7 and 1.2.7 in PI 507354, to identify and map quantitative trait loci (QTL) associated with resistance to SCN HG types 0, 1.2.7, 1.3.6.7 in PI 467312 and resistance to SCN HG types 2.5.7, and 1.2.7 in PI 507354. The study showed that resistance to HG types 1.2.7, and 1.3.6.7 in Pop 467 were conditioned by one dominant and two recessive genes (Rhg rhg rhg) and resistance to HG type 0 was controlled by three recessive genes (rhg rhg rhg). Resistance to both HG types 2.5.7 and 1.2.7 in Pop 507 fit a one dominant and 3 recessive gene model (Rhg rhg rhg rhg). Two to three QTLs were associated with resistance to each HG type (race) in both populaitons.