Near Isogenic Lines Confirm a Soybean Cyst Nematode Resistance Gene from PI 88788 on Linkage Group J

Abstract

that Race 3 SCN resistance in PI 88788 is inherited by three genes, with one recessive and two dominant. The Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is genetic evidence indicates that one of the dominant genes one of the most destructive soybean [Glycine max (L.) Merr.] pests is at a previously unreported locus which was designated worldwide. The most common source of SCN resistance used in soybean breeding in the northern USA is PI 88788. Previous research Rhg5 (Rao Arelli, 1994) the second gene is Rhg4, which has shown that PI 88788 carries a major quantitative trait locus (QTL) maps close to the i gene (Matson and Williams, 1965), conferring SCN resistance on linkage group (LG) G, which is believed and the recessive gene is rhg2. Genetic mapping efforts to be rhg1. The objective of our research was to map and confirm have since shown that PI 88788 has a major QTL on additional SCN resistance QTL in Bell, a cultivar with resistance LG G (Concibido et al., 1997), and a second minor QTL from PI 88788. One hundred four F 4 -derived lines (F 4 population) on LG C2 (Diers et al., 1997a). The QTL on LG G maps developed from crossing the cultivars Bell and Colfax were tested for to the same region where a major resistance locus was associations between 54 molecular markers and resistance to SCN mapped in PI 437654 (Webb et al., 1995), Peking, PI populations PA3 (HG type 7, race 3) and PA14 (HG type 1.3.5.6.7, 90763, PI 89772, and PI 209332 (Concibido et al., 1997; race 14). Three populations of near isogenic lines (NILs) were devel-Concibido et al., 1996; Yue et al., 2001). The resistance oped from F 4 plants heterozygous for a region on LG J where a significant QTL was identified in the F 4 population. The NIL popula-gene in this region has been designated rhg1 in the tions were tested with genetic markers and also for resistance to both literature and Cregan et al. (1999b) reported a linkage SCN populations. In the F 4 population, SCN resistance QTL were of 0.4 centimorgans (cM) between the simple sequence identified at both rhg1 and on LG J. The LG J QTL was confirmed repeat (SSR) marker Satt309 and rhg1 in crosses with in NIL populations and was given the confirmed QTL designation Peking and PI 209332 as sources of SCN resistance. cqSCN-003. The effect of cqSCN-003 was diminished in the NIL Although many QTL have been mapped in soybean, populations compared to the F 4 population. This was at least partially few have been confirmed in additional populations in the result of segregation distortion in the F 4 population between the the same or different genetic backgrounds. The confirregion containing rhg1 and the region containing cqSCN-003. These mation of QTL after initial mapping is a critical step results show the importance of verifying QTL in confirmation populabefore the selection of the QTL with markers in breedtions to estimate accurately their effects.ing programs. Near isogenic line populations are particularly useful for QTL confirmation because they are developed to segregate for QTL ...

Quantitative Trait Loci underlying Resistance to Three Soybean Cyst Nematode Populations in Soybean PI 404198A

“…, but its resistance to SCN races is inconsistent. A QTL was detected on LG J (Concibido et al, 1994(Concibido et al, , 1996(Concibido et al, , 1997 and was recently confirmed by means of near isogenic lines (Glover et al, 2004). LG B1 has been found to be associated with resistance to SCN but the locations of the QTLs declared are significantly inconsistent (Yue et al, 2001a(Yue et al, , 2001bVierling et al, 1996).…”

Arabidopsis genes, AtNPR1, AtTGA2 and AtPR-5, confer partial resistance to soybean cyst nematode (Heterodera glycines) when overexpressed in transgenic soybean roots

“…Resistance to SCN is a multigenic trait and several genetic loci have been mapped [15,27-29,90-93]. Recently, the identity of genes residing at the rhg1 and Rhg4 loci have been reported [6-9] which confer some resistance to SCN.…”

QTLs Associated with Resistance to Soybean Cyst Nematode in Soybean: Meta‐Analysis of QTL Locations

“…Lander and Kruglyak (1995) indicated that there would be many regions with point-wise p value of 0.05 in one genome scan by chance and some will appear again in a second study just by chance. To reduce false positives, only QTLs at LOD $ 3.0 (point-wise p value # 0.001) were used in this study (Table 1), including QTLs detected by Glover et al (2004), and our studies (Guo et al, unpublished; Lu et al, unpublished). It is noted that most studies used SCN populations maintained at the University of Missouri-Columbia.…”

“…In previous soybean SCN-resistant QTL mapping studies, the following threshold levels were used for declaring QTL: (i) LOD 5 2.5 (equivalently p 5 0.003) (Yue et al, 2001a(Yue et al, , 2001b, (kii) p 5 0.002 (Concibido et al, 1994(Concibido et al, , 1996(Concibido et al, , 1997, and (iii) LOD 5 3 (equivalently p 5 0.001) (Webb et al, 1995;Heer et al, 1998;Qiu et al, 1999;Wang et al, 2001, Meksem et al, 2001. Few permutation tests were used to determine threshold levels (Glover et al, 2004). We used three methods to determine threshold value for declaring a QTL at the suggestive level (genome-wide type I error 5 0.63) and at the significant level (genome-wide type I error 5 0.05) for soybean F 2 mapping populations (used in the majority of studies).…”

“…A total of 62 marker-quantitative trait locus (QTL) associations have been reported by 17 papers for resistance to SCN races 1, 2, 3, 5, 6, and/or 14 in a total of 13 soybean accessions (nine resistance sources) Glover et al, 2004). Conflicting results often occurred .…”