Effects of growth stage of resistant and susceptible barley on the Russian wheat aphid, Diuraphis noxia (Homoptera: Aphididae)

摘要

abstract_textpThe Russian wheat aphid, Diuraphis noxia (Mordvilko), is a serious pest of barley in western North America. To help manage this pest, a Russian wheat aphid-resistant germplasm line STARS-9301B was recently released to barley breeders for incorporation into their cultivars. Information about the antixenosis and antibiosis mechanisms of resistance in the 1st-leaf stage was previously reported, but information about these mechanisms of resistance in later plant growth stages has not been available. This study reports on antixenosis and antibiosis tests conducted under controlled conditions on three growth stages of STARS-9301B and 'Morex', a Russian wheat aphid-susceptible malting barley cultivar. In general, aphid reactions in the later growth stages were similar to those on 1st-leaf stage plants except that antixenosis was demonstrated in STARS-9301B when data from all growth stages were combined. Antibiosis continues to contribute to resistance in more mature plants of STARS-9301B. Previous work showed that tolerance is the most important resistance mechanism of STARS-9301B seedlings. Tolerance data for comparing barley entries beyond the seedling stage are not available because a practical, uniform test to determine tolerance levels at these older plant growth stages has not been developed. The results of this study show that spring barley entries can be reliably tested in early growth stages for antixenosis and antibiosis to the Russian wheat aphid./p/abstract_text