Molecular mapping of soybean aphid resistance genes in PI 567541B

Abstract

The soybean aphid (Aphis glycines Matsumura) is an important pest of soybean [Glycine max (L.) Merr.] in North America since it was first reported in 2000. PI 567541B is a newly discovered aphid resistance germplasm with early maturity characteristics. The objectives of this study were to map and validate the aphid resistance genes in PI 567541B using molecular markers. A mapping population of 228 F3 derived lines was investigated for the aphid resistance in both field and greenhouse trials. Two quantitative trait loci (QTLs) controlling the aphid resistance were found using the composite interval mapping method. These two QTLs were localized on linkage groups (LGs) F and M. PI 567541B conferred resistant alleles at both loci. An additive x additive interaction between these two QTLs was identified using the multiple interval mapping method. These two QTLs combined with their interaction explained most of the phenotypic variation in both field and greenhouse trials. In general, the QTL on LG F had less effect than the one on LG M, especially in the greenhouse trial. These two QTLs were further validated using an independent population. The effects of these two QTLs were also confirmed using 50 advanced breeding lines, which were all derived from PI 567541B and had various genetic backgrounds. Hence, these two QTLs identified and validated in this study could be useful in improving soybean aphid resistance by marker-assisted selection.

Mapping soybean aphid resistance genes in PI 567598B

“…Our QTL analysis revealed that only rag3 was detected in the field trial. Zhang et al (2009) also found that the two resistance genes from PI 567541B were expressed differently in the field and greenhouse trials, which was explained by the different aphid biotypes. In fact, Mensah et al (2007) found that the Rag1 in Dowling was first overcome by the Michigan aphids in 2006.…”

Evaluation of the genetic diversity of an Afghan wheat collection based on morphological variation, HMW glutenin subunit polymorphisms, and AFLP

“…The severe climate in Western Afghanistan and Eastern Iran may account for the decreasing population size in the region. According to the meteorological data, the precipitation in this region is very little, suggesting that this region is not suitable for wheat cultivation (Agromet Network 2008, 2009). …”

“…Practical breeding research using landraces has been carried out in several crops, e.g. rice (Hargrove and Cabanilla 1979), maize (Malvar et al 2004), legumes (Isemura et al 2001, Zhang et al 2009) as well as wheat. For bread wheat (Triticum aestivum L.) the importance of landraces is more critical than for other crops because it does not have a direct wild ancestor with the same genomic constitution due to its hybrid origin (Kihara 1944, McFadden andSears 1946).…”

Genetic mapping of three quantitative trait loci for soybean aphid resistance in PI 567324

“…Identification of soybean varieties and plant introductions (PIs) that show resistance to soybean aphids and characterization of the genes from the resistant sources are important early steps in the development of cultivars with resistance to soybean aphid. At least four soybean aphid resistance genes (Rag1, Rag2, Rag3 and rag4) have been reported in different genomic regions on soybean chromosomes 7, 13 and 16 (Li et al, 2007;Mian et al, 2008a;Zhang et al, 2009;Kim et al, 2010;Zhang et al, 2010). Soybean cultivars with a single-aphid resistance gene (for example, Rag1 and Rag2) have been developed, and both genetically modified organism (GMO) and non-GMO cultivars with the Rag1 gene are commercially available (Wiarda et al, 2012).…”

“…Zhang et al (2009) reported that the aphid resistance in PI 567541B was controlled by two QTL located on chromosomes 7 and 13. In a previous study, PI 567324 showed resistance to both biotypes 1 and 2 of the soybean aphid (Mian et al, 2008b).…”