8th INTERNATIONAL WHEAT CONFERENCE

mAPPINg quANTITATIVe TRAIT LoCI IN WheAT INVoLVed
IN ReSISTANCe AgAINST RuSSIAN WheAT APhId
(dIuRAPhIS NoxIA)
Ricciardi M1 , Tocho E2 , Tacaliti MS1 , Vasicek A1 ,
Giménez DO1 , Simmonds J3 , Snape JW3 1, 2
and Castro AM
1 Department of Plant Sciences, Faculty of Agricultural
Sciences, University of La Plata, CC31, 1900-La
Plata, Argentina.
2 National Council of Scientific Research, CONICET, Argentina.
3 John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom
E-mail Address of presenting author: amcastro@isis.unlp.edu.ar
Diuraphis noxia (Russian Wheat Aphid, RWA), the most aggressive pest of wheat, has
evolved several biotypes, virulent to most of the resistance genes. The fast deployment of
resistance requires the assessment of new sources. This paper was aimed at determining
the location of plant-defence genes triggered by RWA in a set of recombinant doubled
haploid (RDH) lines obtained from the cross between UK winter wheat varieties Spark
and Rialto. Both parental lines and 110 RDH were screened for antixenosis, tolerance
and antibiotic mechanisms of resistance with a population of RWA collected in Argentina.
Antixenosis was significantly linked to marker locus Xgwm33 located on 1AS and
to Xgwm193 on 6BS. Tolerance traits showed significant associations with several chromosomes.
The foliar area developed during infestation was significantly associated with
marker loci Xpsp3103 (4DS), and Xgdm3 (5DS). The chlorophyll content in the infested
plants was significantly linked to marker loci Xgwm533 on 3BS, and to Xpsp3094 on 7AL
and the number of expanded leaves was associated with marker loci Xwmc264 (3AS) and
to XwPt-8836 (4DS). Most of the tolerance traits were significantly associated with the
same chromosome interval on chromosomes 4DS and 5DS. The 4DS QTLs are linked to,
or are a pleiotropic effect of, Rht-D1. Most of the antibiosis traits were significantly associated
to the same marker loci on chromosomes 4A (XwPt-7405), 1B (XwPt-9032) and
5B (Xbarc109 and Xbarc74). Several novel genes conferring antixenosis, tolerance and
antibiosis to RWA have been identified and these could be included in wheat cultivars to
enlarge the genetic base of defence against this aphid pest. These new genes can be designated
as new QDn.unlp genes, following the rules for gene nomenclature in wheat.
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