| Wheat aphids were the serious pests in wheat production, In the recent years, Oat bird-cherry(Rhopalosiphumpadi L.) has became the superious aphid species among the three frequent ones(Schizaphis graminum, Rhopalosiphum padi, and Sitobion avenae) during anthesis and milkstage in Sichuan province and Yangtse River basin in China, It not only causes the reduction ofyield and quality, but also transmits barley yellow dwarf virus (BYDV) .Wild relatives in Triticeae possess the important sources of insect resistance. Growthing resistant cultivars is one of elements in the Intergated Pest Management (IPM) of wheat aphids. Evaluatingon resistance of germplasm resources to aphid is a fundamental job in breeding resistant cultivars to aphids.To search for sources of oat bird-cherry (Rhopalosiphum padi (L.)) resistance in Triticeae,1012 accessions from 108 species (subspecies or varieties) of 18 genera and Triticale in Triticeae were systematically evaluated for resistance to this aphid at adult plant stage under natural infestation condition. In addition, Partial biochemical resistant mechanism of wild relatives inTriticeae to R padi were made out. The results were as follows:1. In 1999, 912 accessions from 58 species (subspecies or varieties) of 8 genera in annual Triticeae and Triticale were initially evaluated for resistance to mixture population of aphids, 690 entries exhibited high susceptibility , and 222 entries with slight resistance , to mixture populations of aphids, The percentage was 75.66% and 24.34%, respectively. Of them, Most entries with high susceptibility existed in Triticum aestivum besides 15 accessions of Secale, 2 Triticum macha, 3 T.sphaerococcum, 3 T. turgidum L. dicoccon, 5 T. turgidum L. concv. polonicum, 4 T.5turgidum L. durum, 11 T. turgidum L. var. dicoccoides, 1 T. turgidum L. concv. carthlicum, 2 T. compactwn , JT. turgidum, 3 T. petropavlovskyi and lOTriticale tested.2. 53 accessions from 7 Trificum species (varieties) and 169 accessions from 41 species (varieties) of 7 genera in annual wild Triticeae, Which were regarded as slight resistance to aphids in 1999 , were evaluated for resistance to R. pctdi in adult plant stage by using aphid number ratio, respectively. The results showed that no entries with high resistance to R. padi were found within genus Triticum, Only 7 entries (including 2 Triticum monococcum L. ssp. boeoticum, 2 T. monococcum and 3 T. timopheevi var. araraticum*) exhibited moderate resistance to this pest Of 169 accessions of annual wild relatives (including Aegilops , Crithospsis, Eremopyrum, Dasypyrum, Heteranthelium, Taeniatherum , Hordeum ) tested, High resistance, Moderate resistance, low resistance and susceptibility was 14, 42, 38 and 75 , respectively. The ratio was 8.28%, 24.85%, 22.49% and 44.38%, respectively. 14 accessions with high resistance were found in Aegilops species (including 4 Ae. biuncialis, 1 Ae. columnaris, 3 Ae. triimcialis, 2 Ae. juvenalis, 2 Ae. kotschyi var. variabilis and 2 Ae. umbellulata) .3. 100 accessions of perennial wild relatives from 50 species of 8 genera (including, Agropyron, Elymus, Elytrigia, Hystrix, Hordeum, Kengyia, Psathyrostachys, Leymus, Roegneria and Pseudoroegneria ) were evaluated for resistance to Rpadi in adult plant stage by aphid number ratio in 1999-2000. 7 entries (including 2 Elytrigia repens, 2 Elytrigia elongata, 2Elytrigia ferganensis and 1 Leymus angustus) with high resistance to R. padi were reported for the first time. They are the important sources of resistance to R.padi.4. By artificial aphid inoculation, The life parameter intrinsic innate rate of increase (rm ) ofR. padi feeding on 9 Aegilops species with different level of resistance to this aphid (including Aegilops biuncialis, Ae.juvenalis, Ae. ovata, Ae. kotschyi var. variabilis, Ae. triaristata, Ae. tauschii, Ae. vavilovii, Ae.crassa, Ae.ventricosa) in adult plant and seedling stage weremeasured. Meanwhile,...
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