A common QTL for resistance to races 3 and 9 of soybean cyst nematode.

Resumen

The aim of this work was to study the association between the rhg1 gene and the soybean response to races 3 and 9 of Heterodera glycines (Soybean Cyst Nematode - SCN). The resistant cv. Hartwig was crossed with the susceptible line Y23 and the response to races 3 and 9 was evaluated in 135 and 128 Recombinant Inbred Lines (RIL), respectively. Nematode assays were performed in the greenhouse using a completely randomized design. Eight SSR markers covered a genomic region of 57 cM. Estimated heritabilities of resistance to race 3 and 9 were 80.97 and 80.39%, respectively, showing that a few major genes are segregating in the population. Applying the Composite Interval Mapping (CIM) method, the rhg1 resistance gene was mapped between the SSR markers Satt275 and Satt038 at 2.0 and 3.0 cM from marker Satt038, explaining 29.11 and 20.01% of phenotypic variance in resistance to races 3 and 9, respectively. These SSR markers would be useful tools for assisting in the selection of SCN-resistant genotypes and for expediting the introgression of SCN resistance loci from cv. Hartwig to soybean elite cultivars.