Comparison of tolerance to barley yellow dwarf virus in barley and oats

Abstract

SUMMARYIn a field trial, three varieties each of oats and barley were infected with barley yellow dwarf virus (BYDV) either at growth stage I or at growth stage 8 (Feekes scale), using a virulent isolate of BYDV transmitted by the ‘plum‐grain’ aphid (Rhopalosiphum padi L.). Early infection decreased yields of the susceptible varieties, Blenda oats and Proctor barley, by 97% and 93% those of the more tolerant oat varieties, Albion and CI 7488, b31% and 12%, but had no effect on the yield of the two tolerant Ethiopian barleys, CI 2325 and CI 7224. Late infection decreased grain yield only in Blenda. Mature straw height was decreased by early infection in all three oat varieties and by late infection in Blenda oats and in the barley variety CI 7224. The number of fertile tillers, number of grains per ear and Iooo‐grain weights were decreased in parallel with the decreases in yield, except that early infection increased the number of ear‐bearing tillers in CI 7488 and increased rooo‐grain weight in Albion. The lower yield resulting from late infection in Blenda was not accompanied by a decrease in number of grains per ear.