Identification of wheat germplasm resistant to major Russian wheat aphid biotypes in the United States

Abstract

Russian wheat aphid (Diuraphis noxia Kurdjumov [RWA]) is one of the most invasive and detrimental pests, and host plant resistance is the most efficient approach to manage RWA. Wheat (Triticum aestivum L.) accessions resistant to RWA biotype 1 (RWA1) and biotype 2 (RWA2) were previously identified by screening wheat accessions available at the USDA-ARS National Small Grains Collection. However, RWA biotypic variation necessitates a continuous search for sources of resistance to new RWA biotypes. The objective of this study was to identify wheat accessions resistant to all major RWA biotypes in the United States. A set of 172 RWA-resistant wheat accessions, mainly Iranian landraces, were evaluated for responses to five predominant U.S. biotypes-RWA1, RWA2, RWA3, RWA6, and RWA8-in controlled environments. Of these, 137 accessions showed homogeneous or heterogeneous resistance to at least one biotype, and 14 of them were resistant or highly resistant to all five biotypes. Another set of 19 accessions were resistant or highly resistant to two to four biotypes. These RWA-resistant accessions are valuable sources for RWA resistance improvement, and further purification of some accessions and characterization of the underlying RWA resistance genes are imperative for their utilization in wheat breeding. 1428wileyonlinelibrary.com/journal/csc2

Evaluation of Russian wheat resistance sources with the spectrum of South African Diuraphis noxia biotypes

“…The check genotypes reacted as expected with R check CItr 2401 displaying uniform resistance to all four biotypes. This R check has shown durability in international evaluations with high levels of resistance to U.S. RWA biotypes RWA1, RWA2, RWA3, RWA6, and RWA8 (Xu et al., 2020). PAN 3144 was uniformly R to RWASA1 to RWASA3 and uniformly S to RWASA4, while Hugenoot was uniformly S to RWASA1, RWASA2, and RWASA4.…”

“…A predominantly moderate reaction was observed in four accessions for RWASA1 (‘PI 135064’, ‘PI 243679’, PI 623848, and PI 634770), two for RWASA2 (PI 245432 and PI 634770), RWASA3 (PI 478172 and PI 564250), and RWASA4 (PI 243679 and PI 564250). In the United States, 79.7% of the germplasm used displayed uniform to heterogeneous resistance to at least one biotype, 8.14% to at least two to four biotypes, and 11.05% to all five biotypes (Xu et al., 2020). Wheat germplasm collected from regions where RWA is widespread provides important genetic sources that can be used in crop improvement and breeding programs.…”

“…Xu et al. (2015; 2020) provided the first and only insight to this gap. This is because wheat landraces are collected as mixed populations with untapped wealth of resistance waiting to be explored.…”