三种稻飞虱翅型分化的遗传分析

为了明确褐飞虱Nilaparvata lugens、白背飞虱Sogatella furcifera和灰飞虱Laodelphax striatellus 3种稻飞虱翅型分化的遗传规律与差异,采用翅型筛选与杂交遗传的实验方法,研究了3种飞虱在秧苗期水稻上的翅型选择响应与杂交遗传规律。结果表明:3种稻飞虱的翅型具有较强的选择响应,并且长翅型纯系在白背飞虱中最易筛选得到,灰飞虱的次之,而褐飞虱的最难。3种稻飞虱的长翅(M)雄虫与短翅(B)雌虫配对(M♂×B♀)筛选3～5代后,95%～100%的雄虫和雌虫分别稳定为长翅型和短翅型。筛选和杂交实验结果表明,褐飞虱的翅型决定基本符合常染色体上的一对等位基因调控的从性性状遗传规律,雄虫中长翅为显性,而雌虫中短翅为显性。翅型的表型还受除基因型外的其他条件的影响,利用长翅雄虫与长翅雌虫后代中出现的极少数的短翅雄虫与短翅雌虫进行配对,其后代中各翅型出现的比率与长翅雌虫和长翅雄虫配对的无显著差异;同样,在短翅雄虫与短翅雌虫配对的后代中也有相同的结果。白背飞虱和灰飞虱在该筛选条件下很少有短翅雄虫出现,两者翅型的遗传调控较为相似,可用由两对等位基因控制的性状来解释筛选和杂交实验的结果,其中一对等位基因位于性染色体上,调控雄性的翅型,且长翅为显性;另一对位于常染色体上,调控雌性的翅型,且短翅为显性。据此认为,3种飞虱翅型决定基因的显隐性在不同性别间的差异,以及翅表型与基因型的不一致性,是稻飞虱种群在不同条件下均可灵活调控翅型的重要遗传机制。

STUDIES ON CULTIVAR-INDUCED CHANGES IN INSECTICIDE SUSCEPTIBILITY AND ITS RELATED ENZYME ACTIVITIES OF THE WHITE BACKED PLANTHOPPER, SOGATELLA FURCIFERA (HORVTH) (HOMOPTERA:DELPHACIDAE)

The susceptibility of Sogatella furcifera female adults on N22 to malathion increased as feeding time prolonged, while the day change of susceptibility to isoprocarb showed a inverse tendency. The activities of esterase and carboxylesterase were induced significantly after on N22 for one day, and then declined. The non susceptible level of adults to insecticides and enzyme activities seemed to be heightened after feeding on ASD7, a variety resistant to Nilaparvata lugens. The total phenol content in rice leaf sheath was the highest in N22, and could be regarded as one of the factors, which caused chages in susceptibility of S. furcifera to insecticide after feeding different rice varieties. It was recommended that suitable insecticides and planthopper resistant varieties should be coordinately used in practice so that they contribute more effects respectively.