Genetic mapping of Dn7, a rye gene conferring resistance to the Russian wheat aphid in wheat

Abstract

The Russian wheat aphid is a significant pest problem in wheat and barley in North America. Genetic resistance in wheat is the most effective and economical means to control the damage caused by the aphid. Dn7 is a rye gene located on chromosome 1RS that confers resistance to the Russian wheat aphid. The gene was previously transferred from rye into a wheat background via a 1RS/1BL translocation. This study was conducted to genetically map Dn7 and to characterize the type of resistance the gene confers. The resistant line '94M370' was crossed with a susceptible wheat cultivar that also contains a pair of 1RS/1BL translocation chromosomes. The F(2) progeny from this cross segregated for resistance in a ratio of 3 resistant: 1 susceptible, indicating a single dominant gene. One-hundred and eleven RFLP markers previously mapped on wheat chromosomes 1A, 1B and 1D, barley chromosome 1H and rye chromosome 1R, were used to screen the parents for polymorphism. A genetic map containing six markers linked to Dn7, encompassing 28.2 cM, was constructed. The markers flanking Dn7 were Xbcd1434 and XksuD14, which mapped 1.4 cM and 7.4 cM from Dn7, respectively. Dn7 confers antixenosis, and provides a higher level of resistance than that provided by Dn4. The applications of Dn7 and the linked markers in wheat breeding are discussed.

Genetic mapping of resistance to Diuraphis noxia (Kurdjumov) biotype 2 in wheat (Triticum aestivum L.) accession CI2401

“…Synthetic hexaploids from CIMMYT with resistance to RWA2 have also been reported (Sotelo et al 2009). However, only two other genes with resistance to RWA2, Dn7 and Dn626580, were genetically characterized and mapped prior to this study (Anderson et al 2003;Lapitan et al 2007;Valdez et al 2012). The markers developed in our study will be useful for MAS of Dn2401 in wheat breeding programs.…”

Barley tolerance of Russian wheat aphid (Hemiptera: Aphididae) biotype 2 herbivory involves expression of defense response and developmental genes

“…7 Soon after discovery of D. noxia in the US in 1986, an expedited effort to develop aphidresistant wheat and barley cultivars began 8 and continues today. Ten Dn (Diuraphis noxia resistance) genes from wheat [9][10][11][12][13] and one gene from rye 14 governing resistance to D. noxia have been characterized. The wheat cultivar 'Halt' 15 with resistance based on the single dominant gene Dn4 was introduced for cultivation, followed by 'Prairie Red,' 'Yumar,' 'Prowers,' 'Prowers 99' 16 and 'Ankor' 17 all of which express Dn4.…”

Physiological and Biochemical Responses of Resistant and Susceptible Wheat to Injury by Russian Wheat Aphid

“…The Russian wheat aphid, Diuraphis noxia (Mordvilko), has been a signiÞcant pest of wheat, Triticum aestivum L., and barley, Hordeum vulgare L., in the United States since its Þrst detection in North America in 1986 (Anderson et al 2003). Between 1987 and1992, losses attributed to D. noxia feeding were estimated at $850 million, with Ͼ100 million bushels of grain lost in the western United States alone (Quisenberry and Peairs 1998).…”