| Bemisia tabaci(Gennadius) is a worldwide insect pest. It damages many plants including solanaceae, cucurbitaceae, cotton, and so on. Whitefly control was currently dependent on chemical pesticide. While there were rarely reports about the research and application of resistant variety. In order to provide theoretical basis for pepper resistance mechanisms to whitefly and the production and promotion of pepper resistant varieties,18pepper varieties were chosen to study whitefly selectivity on different peppers and biochemical substance change of peppers infested by B. tabaci in this paper. The main results were summarized as follows:1. The whitefly selectivity on18pepper varieties were studied in this paper. The results showed that whitefly selectivity on different pepper varieties were significantly. After infestation for24h, the number of B. tabaci adults was large on the Zaozaerhao, Dayuniujiaowang, XinxiangNo.8and Gangshanghongjianjiao, it was88.21,86.95,73.8,70.96adults per strain respectively, While the number of B. tabaci was small on Xinyidaisanyingjiao, Zhongjiao No.7, Xinyan988jiaowang and SujiaoNo.5, and it was19.79,14.5,13.16,6.94adults per strain respectively. After infestation for72h, the same change trend was observed.2. The fecundity, development duration and survival rate of B. tabaci on the different pepper varieties were investigated. The results showed that infestation for72h, the number of eggs was700.12eggs per plant on the Gangshanghongjianjiao and it was the largest among the pepper varieties. It was small on Xinyidaisanyingjiao, Zhongjiao No.7, Xinyan988jiaowang, Sujiao No.5and it was112.62,111.35,84.55,67.18eggs per plant, respectively. The development duration and survival rate of B. tabaci were significantly affected by the pepper varieties. The larval development duration was longest for19.72days on Sujiao No.5, and it was shortest for13.12days on Tichun8898xianjiao. The whitefly survival on the Tichun8898xianjiao was highest for66.67%, and it was lowest on the Xinyidaisanyingjiao for32.21%.3. According to the selectivity and adaptability of whitefly on the different pepper varieties,6pepper varieties was selected to study the resistant mechanism of B. tabaci to peppers.The contents of chlorophyll and nutrients was significantly affected by the damage of B. tabaci. The results showed that after9days’damage, compared with control treatment, the contents of chlorophyll in resistant varieties Sujiao No.5and Xinyan988jiaowang were increased by56.1%and19.47%, in medium resistant varieties Xiaoxin No.9and Xiangxin No.3 which were13.5%and0.65%and in susceptible varieties Gangshanghongjianjiao and Dayuniujiaowang which were2.4%and7.07%, respectively. The contents of soluble sugar in Sujiao No.5and Xinyan988jiaowang had the highest increase, and Gangshanghongjianjiao and Dayuniujiaowang had the lowest increase compared to the control. The results showed that the contents of free proline in Sujiao No.5, Xinyan988jiaowang, XiaoxinNo.9and Xiangxin No.3were significantly lower than that in Gangshanghongjianjiao and Dayuniujiaowang. The changes of the contents of soluble protein and Vc had no significant trend among different varieties.4. The activities of SOD and POD and the contents of total phenol and flavonoid were measured in pepper induced by B. tabaci. The results showed that the activity of SOD in all varieties of pepper infested by B. tabaci were increased. After3days’damage, the activity of SOD in Sujiao No.5and Xinyan988jiaowang had a higher increase than in XiaoxinNo.9, Xiangxin No.3, Gangshanghongjianjiao and Dayuniujiaowang. The activities of POD in Sujiao No.5, Xinyan988jiaowang, XiaoxinNo.9and Xiangxin No.3were increased after the damage, however, the activities of POD of Gangshanghongjianjiao and Dayuniujiaowang were decreased. In addition, the increase rate of the activity of POD in Sujiao No.5, Xinyan988jiaowang was high. The contents of total phenol and flavonoid in all variaties of pepper changed after the damage, but showed no significant trend. |
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