Comparison of TAF46 and Zhong 5 resistances to barley yellow dwarf virus from Thinopyrum intermedium in wheat

Barley yellow dwarf virus (BYDV) is one of the most important plant viruses in the world. Two sources of resistance to BYDV derived from Thinopyrum intermediumwere compared in wheat backgrounds. A source of resistance was confirmed in the partial amphiploid TAF46, the group 7 addition line L1, and translocation TC14. The other source of resistance derives from the partial amphiploid Zhong 5 and is present in the group 2 addition line Z6. Six ditelosomic addition lines have been derived from Z6. The resistance of genotypes derived from Zhong 5 is more effective at reducing virus multiplication throughout plant growth than that of genotypes derived from TAF46. The translocation line TC14, derived from TAF46 showed 30% plants escaping virus infection whereas all plants derived from Zhong 5 were infected. This suggests that the two sources of resistance are associated with differing mechanisms of resistance. Methods to better understand the genetic control and the mechanisms of these two resistances are suggested. The pyramiding of different sources of resistance to construct durable resistance is discussed.