Identification of Adzuki Bean Quantitative Trait Loci Associated With Resistance to Soybean Cyst Nematode

Soybean cyst nematode (SCN; Heterodera glycines Ichinohe) infection has recently been shown to cause yield loss in adzuki bean (Vigna angularis [Willd.] Ohwi & Ohashi). Development of SCN-resistant cultivars is used extensively to manage SCN in soybean (Glycine max [L.] Merr.). It is considered the most effective way to manage SCN in adzuki bean. Adzuki bean germplasm “Acc2766” shows high resistance to SCN Races 1 and 3, but it is poorly adapted to the environment of Hokkaido because of late maturity. To enable cultivation in this region, genetic improvement is necessary, and development of DNA markers is expected to accelerate breeding for SCN resistance in adzuki bean. Using GRAS-Di technology, 491 single nucleotide polymorphism markers were identified between “Acc2766” and the susceptible cultivar “Shumari.” QTL analysis was performed using individual F₂ plants derived from a cross between “Shumari” and “Acc2766.” Three QTLs associated with SCN resistance were detected: Qrhgaz-1 on Chromosome 1, Qrhgaz-8 on Chromosome 8, and Qrhgaz-9 on Chromosome 9. The results of tests using BC₃F₃ lines indicated that the introduction of all three QTLs was necessary to confer high resistance. DNA markers closely linked to these QTL regions may be useful for the selection of SCN-resistant lines in future adzuki bean breeding programs.