COMPARISON OF VARIOUS SOURCES OF RESISTANCE TO BARLEY YELLOW DWARF VIRUS IN WHEAT-THINOPYRUM AMPHIPLOID LINES

Barley yellow dwarf virus (BYDV) is one of the most important plant vi ruses in the world. Genes for resistance to BYDV do not exist in wheat (Triticum aestivum). Using the tissue-blot immunoassay, the partial a mphiploid Oklahoma 7211542, which was derived from hybrids of wheat wi th Thinopyrum ponticum was determined to be immune to BYDV. The resist ance in OK7211542 was stronger than that in two other amphiploids deri ved from wheat X Th. intermedium, Zhong 4 and TAF 46, which have been widely used as sources of BYDV resistance. The absence of virus in inf ected OK7211542 plants was not due to inability of the aphids to feed on the plants and transmit the virus, but was due to mechanisms that r educe virus multiplication and inhibit transport of virus. The new sou rce of immunity to BYDV in OK7211542 offers great potential for transf erring BYDV resistance into wheat.