Abstract
In the context of the reduction of insecticide availability, varietal innovations associated with resistance or tolerance to vector-borne viral diseases represent major ecological, agronomical and economical challenges for future management strategies. Yellow dwarf disease (YDD) is one of the most important viral diseases on small grain cereals worldwide. In France, yield losses are mainly due to isolates of barley yellow dwarf virus PAV (BYDV-PAV; species Luteovirus pavhordei). BYDV-PAV isolates are efficiently transmitted by Rhopalosiphum padi. Several experiments of aphid-mediated inoculation of an isolate of BYDV-PAV were carried out under controlled conditions to evaluate a set of 14 barley genotypes carrying Ryd2 (n = 7), Ryd3 (n = 4) or Ryd2/Ryd3 (n = 3) genes. Results show that Ryd genes limit the success of infection (low infection rates) and increase the latency period in infected hosts. These characteristics allow the Ryd2- and Ryd3-genotypes to be described as partially resistant to YDD. Furthermore, this work highlights i) the role of barley’s genetic background on the partial resistance phenotype provided by Ryd genes and ii) the increased BYDV-PAV-resistance phenotype of Ryd2/Ryd3 pyramided genotypes. This characterization of virus/Ryd gene interactions should be considered for future breeding programs against this viral disease.