Locations of Quantitative Trait Loci Conferring Russian Wheat Aphid Resistance in Barley Germplasm STARS‐9301B

Abstract

Russian wheat aphid (RWA, Diuraphis noxia Kurdjumov) infestations reduce grain yield and quality and have caused more than $1 billion in losses for barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) in the western United States since 1986. Our objective was to map quantitative trait loci (QTLs) conferring resistance to RWA feeding damage in the germplasm line STARS‐9301B via polymerase chain reaction–based marker assays of 191 F2–derived F3 families from the cross ‘Morex’/STARS‐9301B. Morex is a susceptible six‐rowed malting barley. STARS‐9301B is a selection from RWA‐resistant Afghanistan introduction PI366450. Replicated seedling reactions to RWA infestations were used to phenotype each family based on a 1 to 9 visual rating of chlorosis. A total of 107 molecular markers was used to construct a linkage map. Quantitative trait loci analysis identified two major QTLs for resistance. The QTL on the short arm of chromosome 1H was associated with B‐hordein and explained 26% of the variation for RWA reaction. A QTL on chromosome 3H associated with EBmac0541 explained 38% of the variation. A minor QTL on chromosome 2H was associated with marker GBM1523 and explained 6% of the variation. A combined analysis indicated that the marker–QTL associations explained 59% of the phenotypic variation for RWA resistance. These markers linked with QTLs will be valuable in breeding for RWA resistance. Pyramiding the genes from STARS‐9301B with genes from other sources will be helpful for long‐term protection against RWA in barley.

Genetic Diversity for Russian Wheat Aphid Resistance as Determined by Genome‐Wide Association Mapping and Inheritance in Progeny

“…The 1H and 3H haplotypes confirmed QTL identified in previous AM and biparental studies (Mittal et al, 2008(Mittal et al, , 2009Dahleen et al, 2012Dahleen et al, , 2014. The 1H and 3H haplotypes confirmed QTL identified in previous AM and biparental studies (Mittal et al, 2008(Mittal et al, , 2009Dahleen et al, 2012Dahleen et al, , 2014.…”

“…But the biparental studies indicated that STARS9301B had a QTL associated with resistance on the short arm of 2H (Rdn3) lacking in STARS9577B, while the comparable region in this study indicates the allele associated with resistance at 2H marker SCRI_RS_195810 was present in both STARS lines (Mittal et al, 2008(Mittal et al, , 2009). For example, SSR analyses of progeny from biparental crosses of STARS9301B  Morex and STARS9577B  Morex showed QTL associated with resistance in the short arm of chromosome 1H (Rdn2) and the long arm of 3H (Rdn1) in the same positions as the 1H and 3H haplotypes from this study.…”

Biotype Differences for Resistance to Russian Wheat Aphid in Barley

“…This group included STARS9577B, which has been used as a resistance source in two of the four USA1 resistant cultivars (Mornhinweg, 2011). Rdn3, on chromosome 2HS, which was present in STARS9301B but not in STARS9755B (Mittal et al, 2008(Mittal et al, , 2009), appears to also influence resistance to Hun-gary1. The locus Rdn1, for resistance to USA1 found in these two lines, was located on the long arm of chromosome 3H (128-138 cM) and also appears to affect the reaction to Hungary1.…”

“…Further study indicated that the two CIMMYT lines, derived from the crosses Gloria/Come and ASE/2CM//B76BB, contained the same dominant gene . An additional QTL on 2H (Rdn3) was present in STARS9301B and in its resistant parent accession, and chlorosis ratings on STARS9301B are consistently one point lower than those of STARS9577B (Mittal et al, 2008(Mittal et al, , 2009Nieto-Lopez and Blake, 1994;Raman and Read, 2000). The RWA biotype USA1 has been used to examine the genetics of resistance in the first two lines extensively used to develop RWA resistant germplasm, STARS9301B and STARS9577B.…”

Genetic inheritance analysis of melon aphid (Aphis gossypii Glover) resistance in cucumber (Cucumis sativus L.)

“…The average number of aphids per plant was used as a basis for identifying aphid resistance in bean (Han et al 1991). There is evidence for genetic control of aphid resistance in many crops, including tomato (Solanum lycopersicum) (Rossi et al 1998), wheat (Triticum aestivum) (Liu et al 2005), barley (Hordeum vulgare) (Mittal et al 2008), melon (C. melo) (Sarria et al 2008;Brotman et al 2002), barrel clover (Medicago truncatula) (Klingler et al 2005), maize (Zea mays) (So et al 2010) and soybean (Glycine max) (Kim et al 2010a, b;Ohnishi et al 2012). However, little is known about the inheritance of aphid resistance in cucumber.…”