|CARVER, BRETT - Oklahoma State University|
|ZHAN, KEHUI - Henan Agricultural University|
|Mornhinweg, Dolores - Do|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2014
Publication Date: 2/24/2015
Citation: Xu, X., Bai, G., Carver, B.F., Zhan, K., Huang, Y., Mornhinweg, D.W. 2015. Evaluation and reselection of wheat resistance to Russian wheat aphid biotype 2. Crop Science. 55(2):695-701.
Interpretive Summary: Russian wheat aphid (RWA) is a serious wheat pest that causes heavy losses in many countries. Host plant resistance is an environmentally friendly alternative to chemical control and plays a vital role in helping ensure food security for the world's rapidly rising population. RWA resistance genes have been identified and deployed in wheat cultivars. However, the emergence of a new RWA biotypes, RWA2, promotes the need for identifying novel resistance genes to withstand it. When RWA2 was discovered in 2003, it was virulent to all known resistance genes except Dn7, the rye-derived RWA resistance gene associated with undesirable quality traits. Currently, Dn7 is widely used in wheat breeding programs. In this study, we evaluated RWA2 resistance of an international collection of landraces, cultivars, and genetic stocks to find new resistance sources. We identified nine pure landraces resistant to RWA2. In addition, highly resistant plants were also found in 28 landraces that are not pure. Reselection was conducted to purify some potential resistance sources, and resistant lines were obtained. Reselection line PI 626759-20-32 offered a high level of resistance to RWA2, and has the potential to supplement or replace Dn7 in wheat breeding.
Technical Abstract: Russian wheat aphid (RWA, Diuraphis noxia, Mordvilko) biotype 2 (RWA2) is virulent to most known RWA resistance genes and severely threatens wheat production in the hard winter wheat area of the US western Great Plains. We determined RWA2 reactions of 386 cultivars from China, 227 advanced breeding lines and recently released cultivars from the USA, 505 landraces from countries where RWA is endemic, and 31 genetic stocks developed in the USA, Australia, Canada, and Russia. The majority of wheat accessions from China and the USA were highly susceptible to RWA2. Only nine landrace accessions produced a homogeneous resistant reaction. In addition, highly resistant plants were identified in 28 heterogeneous landraces. Thus reselection was conducted to purify some potential resistance sources, and the single-plant progeny of 220 selected plants were evaluated. Homogeneous resistant or highly resistant lines were identified from seven previously heterogeneous landraces. Reselection line PI 626759-20-32 offered a high level of resistance similar to lines carrying Dn7, the rye-derived resistance gene associated with undesirable bread-making quality. PI 626759-20-32 has the potential to supplement or replace Dn7 as a new RWA2 resistance source in wheat breeding.