| Wheat is an important food source in China. So, how to manage the pest and disease during its growth has been attracting attention.. Wheat aphids. including Schizaphis graminium (Rondani), Rhopalosiphum padi linne and Sitobion avenae ) distributing -broadly in the world, feed on wheat, maize and other crops as well in most region of China, transmit BYDV and so on, and resulting in loss of crop yield. So, it is necessary to find an effective way to prevent them. How to manage them becomes even more serious with broad application of toxic pesticides . At the same time, yield is not the only scaling criteria, because more and more people prefer productions without rudimental pesticide.Growing resistant cultivars is one of elements in the Intergated Pest Management (IPM) of wheat aphids. To search for sources of aphid resistance in Triticeae,22 accessions of Aegilops were systematically evaluated for resistance to Sitobion avenae. In addition, partial biochemical resistant mechanism of wild relatives in Aegilops were made out. The result as follows:1. 22 accessions of Aegilops were evaluated for resistance to Sitobion avenae by aphid number ratio, 2 Ae.kotschyi var.variabilis, 1 Ae.biuncialis, 1 Ae.juvenalis that with high resistance were found, especially Ae.biuncialis has the highest resistance; while Ae.vavilovii , Ae ventricosa and Ae.crassa exhibited high susceptibility.2. Three methods to evaluate the resistance of 13 entries from Aegilops species to aphids were compared, the result were identical. The coincidence between the method of weight-loss and the method of aphid number ration were 84.6% , 53.6% respectively, when resistance level was divided into three classes and six classes. The coincidence between the method of contents of chlorophyll and the method of aphid number ration were 69.2%, 46.2% respectively, when resistance level was divided into three classes and six classes. The correlation was shown between contents of chlorophyll and aphid number ratio( r= -0.542 ) and the correlation between weight-loss and aphid number ratio( r= 0.041) was also shown.3. The nonpreference mechanism of wheat aphids was conducted, the relationship between the amount of winged aphids in the 13 Aegilops species and time is regular by regression analysis. b,the change speed of the amount of winged aphids were more than 1 in Ae.crassa-.Ae tauschii.Ae ventricosa and Ae.vavilovii, especially inAe ventricosa, was 1.5476, So, the aphid has much favorite to it; b is negative in AS48 Ae.biuncialis and AS112 Ae. juvenalis, and so on,especially in AS28 Ae. kotschyi var.variabilis was -1.0595.4. The effect of 8 Aegilops species on main life parameters, e.g.the survivals, growth and development, reproduction of Sitobion avenae were studied, the highest death ratio of Sitobion avenae is 1.58 times than that of the lowest. The highest net reproduction ratio is as three times as that of the lowest; rm increases with the declining of resistance level, rm of aphid eating Ae.biuncialis is the lowest, so, Ae.biuncialis has the highest resistance to Macrosiphum avenae.5. The relationship between the contents of the secondary substances and Aegilops resistance to Sitobion avenae were studied. The results indicated that there are no obvious correlation between solvable sugar and rm of Sitobion avena, between content of protein and rm ,between content of total phenols and rm in leaves of adult Aegilops species, while the correlation between DIMBOA and rm is significantly negative (rm = 0.1064-0.3371x, R2 = 0.824). So, DIMBOA may be an important factor of the resistance to Sitobion avenae. |
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