Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2004
Publication Date: 4/1/2005
Citation: Hesler, L.S. 2005. Resistance to rhopalosiphum padi (homoptera: aphididae) in three triticale accessions. Journal of Economic Entomology. 98:603-611.
Interpretive Summary: The bird cherry-oat aphid (BCOA) is a nearly worldwide aphid pest of small grains that causes direct yield loss by reducing particular components such as the numbers of spikelets and seeds. Limiting infestations of BCOA can prevent direct damage and sustain yield of small grains. Host-plant resistance is a desirable strategy for limiting aphid infestations because it is economical and environmentally sound. Relatively little research has been conducted in regard to testing for resistance to BCOA in rye and wheat-rye hybrids, known as triticale, but several rye and triticale lines are resistant to other small-grain aphids. Resistance to BCOA was identified and characterized in three triticale lines (H7089-52, Stniism 3, and 8TA5L) as a delay in the time for aphids to reproduce, a decreased number of progeny, or both. The results suggest that these three triticale lines may be important sources for use in breeding small-grain cultivars with resistance to BCOA.
Technical Abstract: I tested for resistance to Rhopalosiphum padi L., the bird cherry-oat aphid, among twelve grass accessions (8 wheat [Triticum aestivum L.], 3 triticale [XTriticosecale Wittmack], and 1 XElytricum [Elytrigia elongata [Host] Nevski ×Triticum aestivum hybrid]). To test for antibiosis to R. padi among the accessions, I evaluated population growth of R. padi over 13 d, the number of days to reproduction of individual R. padi, and number of progeny produced in 7 d per individual R. padi. I also tested for antixenosis in no-choice nymphiposition tests and in choice tests to measure host selection by winged R. padi. The triticale accessions '8TA5L' (PI 611760) and 'Stniism3' (PI 386156) each reduced population growth of R. padi compared to various other accessions. Stniism 3 and the triticale, 'H7089-52' (PI 611811), prolonged the time to reproduction by R. padi compared to that on the wheat accessions 'Arapahoe' (PI 518591), 'KS92WGRC24' (PI 574479) and 'MV4' (PI 435095). Rhopalosiphum padi produced the fewest progeny on Stniism 3, and fewer progeny on 8TA5L than on Arapahoe, H7089-52, KS92WGRC24 and MV4. Accessions were not antixenotic to R. padi. In no-choice tests, the number of nymphs deposited by R. padi did not differ among accessions. In choice tests, the number of winged R. padi settling upon plants did not differ among accessions. My study has identified three triticale accessions, 8TA5L, H7089-52 and Stniism3, as sources of antibiosis resistance to R. padi. Additional studies should determine the genetics of R. padi resistance in these triticale accessions and clarify their potential for use in small-grain breeding programs.