Abstract:

The linkage between inheritance of virulence and sex in the brown planthopper (BPH), Nilaparvata lugens (Stål) was studied based on two virulence indices,  honeydew excretion and weight gain. Virulence in three host related populations of BPH, which had been reared on rice variety TN1, Mudgo and ASD7 for 82 generations respectively, were studied with honeydew excretion and weight gain of female adult tested in 48 h. Virulence of BPH from avirulent BPH population (TN1 population, most individuals are avirulent), were significantly weaker than that from virulent BPH populations (Mudgo or ASD7 populations, most individuals are virulent). So, crosses and backcrosses were conducted between avirulent and virulent population to study the genetic model of virulence of BPH. In honeydew excretion testing, the results showed that the mean honeydew excretion of famale adults was significantly different in reciprocal cross populations (F₁ populations), which indicated that there were obvious differences in the virulence of these populations. The same result was obtained with the index of weight gain. The above results suggest that the inheritance of virulence of the brown planthopper may be sex-linked.

Key words: Nilaparvata lugens, rice, honeydew excretion, weight gain, virulence, inheritance, sex