|KAZI, SAMREEN - Southern Illinois University|
|SCHULTZ, JEFF - Louisiana Technical University|
|BOND, JASON - Southern Illinois University|
|HASHMI, RIZWAN - Southern Illinois University|
|LIGHTFOOT, DAVID - Southern Illinois University|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/6/2009
Publication Date: 10/25/2009
Citation: Kazi, S., Schultz, J., Bond, J., Arelli, P.R., Hashmi, R., Lightfoot, D.A. 2009. Iso-lines and Inbred-lines Confirmed Loci that Underlie Resistance from Cultivar ‘Hartwig” to Three Soybean Cyst Nematode Populations. Theoretical and Applied Genetics. 120:633-644.
Interpretive Summary: Soybean yields worldwide are limited by the soybean cyst nematode , a microscopic size round worm attaching the roots of the plant. Resistant cultivars have been the most effective means of controlling the pest. Nematode populations are variable and have adapted to reproduce on resistant cultivars. Soybean cultivar Hartwig was released due to its comprehensive resistance genes to most populations of the nematode. Since Hartwig has a combination of resistance genes from Peking and PI 437654 soybeans, its genetics of resistance is not well understood. Cultivars Hartwig and Flyer were crossed to develop progenies called recombinant inbred lines (RILs). DNA markers were used to confirm a new resistance gene or QTL (Quantitative trait locus) in RILs that can be used to broaden resistance to the nematode. This information will help soybean breeders to develop new cultivars with better resistance to the nematode, especially using marker assisted breeding method.
Technical Abstract: Soybean [Glycine max (L.) Merr.] cultivars vary in their resistance to different populations of the soybean cyst nematode (SCN), Heterodera glycines. Populations are classified into groups called HG Types. The rhg1 locus on linkage group G underlying resistance to HG Type 0 was necessary for resistance to all other HG types. However the loci for resistance to H. glycines HG Type 1.3- (race 14) and HG Type 1.2.5 (race 2) of the soybean cyst nematode may vary in their locations. The objectives were to compare the inheritance of resistance to three nematode HG Types in a population segregating for resistance to SCN and to identify the underlying quantitative trait loci (QTL). Hartwig, a soybean cultivar resistant to most SCN HG Types was crossed with the susceptible cultivar Flyer. A total of 92 F5-derived recombinant inbred lines (RILs) and 144 molecular markers were used for map development. The rhg1 associated QTL found in earlier studies was confirmed and shown to underlie resistance to all three HG Types in RILs (Satt309; HG Type 0, P=0.0001 R2 = 22%; HG Type 1.3.., Satt275, P = 0.001, R2 = 14%) and NILs (Satt309; HG Type 1.2.5, P-0.001 R2 = 24%). A new QTL underlying resistance to HG Type 1.2.5-was detected on LG D2 (Satt574; P=0.001, R2 = 11%) among 14 RILs resistant to the other HG types and was confirmed in a small NIL population consisting of 60 plants of ten genotypes (P=0.04). This QTL is located in an interval previously associated with resistance to both SDS (Sudden Death Syndrome) leaf scorch and SCN HG Type 220.127.116.11. The QTL detected will allow marker assisted selection for multigeneic resistance to complex nematode populations in combination with other agronomic traits.