Categories and Inheritance of Resistance to Russian Wheat Aphid (Homoptera: Aphididae) Biotype 2 in a Selection from Wheat Cereal Introduction 2401

Abstract

The Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Homoptera: Aphididae), is one of the most devastating insect pests of wheat (Triticum spp.) and barley (Hordeum spp.) in the world. Yield losses and control costs are valued at several hundred million dollars each year. The use of D. noxia-resistant cultivars is an ecologically, economically, and biologically sound method of managing this pest. Several D. noxia resistance (Dn) genes from wheat have been used to develop cultivars resistant to D. noxia. However, a new U.S. D. noxia biotype (biotype 2) in Colorado is virulent to all known Dn genes except the Dn7 gene from rye (Secale spp.). Hence, there is an immediate need to identify and characterize unique sources of D. noxia resistance to biotypes. In this article, we report resistance to D. noxia biotype 2, identified in a selection from wheat cereal introduction (CItr) 2401, that is controlled by two dominant genes. CItr2401 has a strong antibiosis effect that is exhibited as a reduced intrinsic rate of increase of D. noxia biotype 2. CItr2401 plants also exhibit tolerance to leaf rolling and chlorosis. No antixenosis was detected in CItr2401.

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

“…This suggests the presence of a second gene with minor effect contributing to resistance in CI2401. This result is supported by the previous study of Voothuluru et al (2006) suggesting the likely presence of two genes conferring resistance in CI2401 based on segregation of F 2 and F 4 progenies from a cross between CI2401 and the susceptible parent 'Karl'. This minor gene effect was possibly not detected in our inheritance studies using F 2 and F 3 populations because chlorosis and leaf rolling scores were combined to categorize the responses as resistant or susceptible.…”

“…Voothuluru et al (2006) also reported the likely presence of two dominant genes conferring resistance to RWA2 in CI2401. As pointed out by Voothuluru et al (2006), one of the genes could not be Dn4 since RWA2 is virulent to Dn4. The resistance gene(s) in CI2401 have not been genetically mapped.…”

“…With regard to the number of resistance genes in CI2401, Dong et al (1997) reported that there are two genes in CI2401 for resistance to biotype RWA1, one of which is Dn4 located on chromosome 1D. Voothuluru et al (2006) also reported the likely presence of two dominant genes conferring resistance to RWA2 in CI2401. As pointed out by Voothuluru et al (2006), one of the genes could not be Dn4 since RWA2 is virulent to Dn4.…”

Comparison of categories of resistance in wheat and barley genotypes against biotype 2 of the Russian wheat aphid, Diuraphis noxia (Kurdjumov)

“…The results of our antixenosis assays are in agreement with those of Voothuluru et al (2006) and detected no (Lage et al 2004;Miller et al 2003). However, Randolph et al (2005) noted no antixenosis among several D. noxia-resistant wheat cultivars.…”

Mapping quantitative trait loci for growth responses to exogenously applied stress induced hormones in wheat

“…It was previously reported that S6A maintained a normal accumulation of dry matter in aerial and root parts when subjected to greenbug infestation with values similar to those in uninfested controls (Castro et al 2007). Voothuluru et al (2006) also reported that tolerance to RWA biotype 2 in line Cltr2401 was based on the maintenance of root dry weight under infestation. The DHR mean values for ADWC and RDWC were between the parental lines, indicating additive eVects on trait expression.…”