Study On The Resistance Mechanism Of Spring Wheat To Aphids And The Effect Of Aphids On Wheat Flour Quality

Wheat aphid (Homoptera: Aphididae.) is one of the most important wheat (Triticum aestivum L.) pests in the world. Schizaphis graminum (Rondani) and Sitobion avenae (F.) are commonly observed on wheat throughout China, and it is Sitobion avenae (F.) that could seriously cause damage of spring wheat in Hexi Corridor of Gansu province.In order to develop aphid resistant variety and to reduce damage of wheat aphid, it is necessary to understand the resistant mechanism of spring wheat to aphids. The objective of the present study was to reveal the relationship between 9 morphological characters and 4 biochemical substances of 12 varieties with different degree of resistance to aphid. In addition, the effect of aphid feeding on flour quality was investigated. The main results as follows:1. The results of the correlation analysis for 9 morphological characters (flag leaf, chlorophyll content, flag leaf hair length, flag leaf hair density, flag lardaceous content, spike density, flag leaf area, plant height, tiller, awn length) of 12 varieties with different degree of resistance to aphid indicated that flag leaf chlorophyll content, flag leaf hair length, flag leaf hair density, flag, lardaceous content and spike density displayed negatively correlation with aphid ratio, and both the area of flag leaf and plant height displayed positively correlation with aphid ratio, while weak correlation was obtained for awn length and tiller numbers with aphid ratio.2. Positive correlation was revealed for total phenols content and proline content with aphid ratio, while DIMBOA content and soluble sugar content displayed negative correlation with aphid ratio.3. The result indicated that aphid feeding could result in decreased wheat flour quality. After aphid feeding, flour protein content, sendimentation volume, baking strength, paste extensibility, wet gluten content decreased, while ash content and granularity increased. However paste elasticity did not changed. Strong correlation was observed for baking strength, and paste extensibility with aphid ratio, and the coefficient was r=-0.67(P=0.0168)and r=-0.781(P=0.0131), respectively. Furthermore, the change of protein content displayed negative correlation with the change of paste extensibility, baking strength and granularity, and positive correlation was obtained between the change of paste extensibility and the change of baking strength.