Studies On Restoring Ability And Resistance Of Rice Varieties To Brown Planthopper And Rice Gall Midge

In this thesis, restoring ability of rice varieties resistance to brown planthopper (BPH )(Nilaparvata lugens (Stal) ) biotype II and rice gall midge(GM)(Orseolia oryzaeWood-Mason) China type IV were tested, resistance of F₁ generation originated by BPH-and GM-resistant varieties crossed with rice male sterility lines were evaluated, genetic of resistance of IR29692-65-2-3-3 to BPH was analyzed, effects of rice varieties on BPH were evaluated. AMMI model was applied as the methods to study the stability of rice varieties resistance to BPH. mechanisms of rice varieties resistance to GM were studied . The main results were as follows:1. F₁ generation originated by IR29692-65-2-3-3 was resistant or moderately resistant to BPH. F₁ generation originated by IR29692-65-2-3-3, IR32, IR25924-51-2-3 had a relatively high seed-setting percentage, among which, seed-setting percentage of F| generation originated by IR29692-65-2-3-3 crossed with Qi A, Zhi A, Pei'ai 64S, Xian A , Gang 46 A were 03.26%, 77.93%, 75.92%, 73.43% , 76.45% respectively ,and theoretical yield of these combinations were 7.9385 , 8.1553, 7.3658, 7.7012 and 7.4695t/hm² respectively. In addition, most F₁ generation planted as late cropping rice in Nanning presented moderate plant height and growth duration.2. The resistance of IR29692-65-2-3-3 to BPH was controlled by a single dominant gene.3. BPH biotype II was tended towards oviposit on susceptible varieties. Compared with TNI, The BPH biotype II caged on resistant varieties has long nymphal development duration and adult preoviposition period, short longevity, high mortality and low fecundity.