Genetic Mapping of Wheat Curl Mite Resistance Genes Cmc3 and Cmc4 in Common Wheat

Triticum tauschii) (Thomas and Conner, 1986; Whelan and Thomas, 1989) and the Cmc2 gene transferred to To diversify the genetic base of resistance in wheat (Triticum aesti6D from Agropyron elongatum (Host). Beauv. (Martin vum L.) to the wheat curl mite (WCM), Aceria tosichella Keifer, resiset al., 1976; Whelan and Hart, 1988). An unnamed gene tance to this pest was transferred from the dipolid goatgrass Aegilops was transferred to chromosome 6A of wheat from Haytaushcii (Coss.). Schmal. to the hard red winter wheat germplasm KS96WGRC40 by backcrossing to the cultivar TAM 107. KS96WGRC40 naldia villosa (L.) Schur as a T6AL•6VS translocation has WCM resistance derived from both Ae. tauschii and rye (Secale (Chen et al., 1996). In addition, WCM resistance was cereale L.). The objectives of this study were to determine if a unique transferred to the hard red winter wheat cultivar TAM WCM resistance gene was transferred from Ae. tauschii to KS96107 from ‘Amigo’ wheat (Cox 1991), which contains the WGRC40 and to determine the chromosome and linkage map locawheat–rye translocated chromosome T1AL•1RS (Lapitions of the WCM resistance genes in the germplasm. The rye-derived tan et al., 1986; Schlegel and Kynast, 1987). The rye WCM resistance gene in TAM 107 and KS96WGRC40, designated segment in the translocation chromosome was derived Cmc3, is present on wheat–rye translocation T1AL•1RS. Marker analfrom ‘Insave F. A.’ rye through the triticale ‘Gaucho’ ysis of a segregating F2 population revealed that the rye-specific micro(CI15323) (Sebesta et al., 1994a,b). Although Wood et satellite marker SCM09 can be used to select wheat lines carrying the al. (1995) demonstrated that Insave F. A. rye and Gau1RS segment and Cmc3. Allelism tests indicated that the Ae. tauschiicho triticale both are resistant to WCM, cosegregation derived WCM resistance gene in KS96WGRC40, designated Cmc4, of the T1AL•1RS chromosome with WCM resistance segregated independently of the Cmc1 gene previously transferred has not been demonstrated and the WCM resistance from this species. Molecular and cytogenetic analyses located Cmc4 gene(s) has not been named. The cultivar TAM 107 has distally on chromosome 6DS flanked by markers Xgdm141 (4.1 centimorgans, cM) and XksuG8 (6.4 cM). The linked markers may be used been widely grown in the western part of the southern in wheat breeding programs for the selection of lines resistant to Great Plains and WCM collections from western Kansas WCM and for gene pyramiding. have been identified that are able to colonize TAM 107 (Harvey et al., 1999). To diversify resistance to the WCM in hard winter T wheat curl mite is an arthropod pest of wheat wheat germplasm, resistance was transferred from acwhich vectors the Wheat streak mosaic virus (WSMV) cession TA 2397 of the diploid relative Ae. tauschii to the (Slykhuis, 1955; Nault and Styer, 1970). The WSMV causes wheat germplasm KS96WGRC40 (Cox et al., 1999) by significant yield losses in wheat growing areas of the backcrossing into a TAM 107 background. The germU.S. and the Canadian Great Plains (Sim and Willis, plasm line has WCM resistance derived from both TAM 1988; Bockus et al., 2001). In addition, nonviruliferous 107 and Ae. tauschii accession TA 2397. To characterize WCM infestations may reduce wheat grain yields by as and name the gene(s) transferred to KS96WGRC40 from much as 17% (Harvey et al., 2000). Mite resistant cultiTA 2397, it is necessary to also characterize the ryevars show lower rates of WSMV infection than mite derived resistance in the recurrent wheat parent. The susceptible cultivars (Conner et al., 1991; Harvey et al., objectives of this study were to determine if a unique 1994), demonstrating the importance of host resistance WCM resistance gene was transferred from Ae. tauschii to an arthropod vector in controlling a plant virus. to KS96WGRC40 and to determine the chromosome Two genes conferring resistance to WCM have been and linkage map locations of the WCM resistance genes named, Cmc1 transferred to wheat chromosome 6D from in KS96WGRC40. Aegilops tauschii (Coss.). Schmal. (syn. Ae. squarrosa L.; MATERIALS AND METHODS R. Malik, C.M. Smith, and T.L. Harvey, Dep. of Entomology; G.L. Brown-Guedira, USDA-ARS-NPA, Plant Science and Entomology Plant Material Research Unit, Dep. of Agronomy; and B. S. Gill, Dep. of Plant PaKS96WGRC40 is a hard red winter wheat germplasm with thology, Kansas State Univ., Manhattan, KS 66506, USA. Joint contribution of USDA-ARS and the Kansas Agric. Exp. Stn.. Contribution the pedigree KS93U69*3/TA 2397 (Cox et al., 1999). KS93U69 no. 02-301-J. This work was financially supported by the Kansas State is a leaf rust-resistant germplasm with the pedigree TAM 107*3/ University Plant Biotechnology Center, CSREES Grant KAN493, TA 2460. TA 2460 is a leaf rust-resistant accession of Ae. and the USDA-ARS, Plant Science and Entomology Unit, USDAtauschii. The WCM resistance of KS96WGRC40 is derived ARS State University, Manhattan, KS. Mention of a proprietary name from TAM 107 and from Ae. tauschii accession TA 2397 origiin this article does not imply approval to the exclusion of other suitnally collected from Afghanistan. Other lines included in the able products. Received 8 April 2002. *Corresponding author (gbg@ ksu.edu). Abbreviations: cM, centimorgans; WCM, Wheat Curl Mite; WSMV, Wheat streak mosaic virus. Published in Crop Sci. 43:644–650 (2003).