| Title: | Near Isogenic Lines Confirm a Soybean Cyst Nematode Resistance Gene from PI 88788 on Linkage Group J |
| Authors: | Glover, K.D., Wang, D, Arelli, P.R., Calson, S.R., Cianzio, S.R., Diers, B.W. |
| Source: | Crop Sci. 2004, 44(3):936-941 |
| Abstract: | Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is one of the most destructive soybean [Glycine max (L.) Merr.] pests worldwide. The most common source of SCN resistance used in soybean breeding in the northern USA is PI 88788. Previous research has shown that PI 88788 carries a major quantitative trait locus (QTL) conferring SCN resistance on linkage group (LG) G, which is believed to be rhg1. The objective of our research was to map and confirm additional SCN resistance QTL in Bell, a cultivar with resistance from PI 88788. One hundred four F4–derived lines (F4 population) developed from crossing the cultivars Bell and Colfax were tested for associations between 54 molecular markers and resistance to SCN populations PA3 (HG type 7, race 3) and PA14 (HG type 1.3.5.6.7, race 14). Three populations of near isogenic lines (NILs) were developed from F4 plants heterozygous for a region on LG J where a significant QTL was identified in the F4 population. The NIL populations were tested with genetic markers and also for resistance to both SCN populations. In the F4 population, SCN resistance QTL were identified at both rhg1 and on LG J. The LG J QTL was confirmed in NIL populations and was given the confirmed QTL designation cqSCN-003. The effect of cqSCN-003 was diminished in the NIL populations compared to the F4 population. This was at least partially the result of segregation distortion in the F4 population between the region containing rhg1 and the region containing cqSCN-003. These results show the importance of verifying QTL in confirmation populations to estimate accurately their effects. |