The DNA Polymorphism Of Populations With Different Virulence And TN1 Population's Marker Of Nilaparvata Lugens (St(?)l)

We started with the DNA polymorphism of host-associated populations of N.lugens with different virulence, and seeked the specific band of a population as a marker. On the basis of this marker, we got two relatively pure populations, and conducted biological comparison and genetic experiments. We preliminarily researched the variation of virulence of N.lugens, the main results were as follows:1. The analysis of genetic diversity of different virulence populations showed, whether female or male, the genetic diversity of inter-populations was greater than that of intra-populations, the TNI populations was reared on susceptible rice varieties showed the largest genetic variation. In the dendrogram obtained with UPGMA analysis based on the standard of similarity index (SI), every female individual of a population could be clustered into a group with no exception, and so did the male. This provided the first clearly evidence confirming that significant genetic differentiation existed between host-associated N.lugens populations with different virulence. It was also found that male and female individuals were grouped into two discrete classes, which suggested that the inheritance of virulence of N.lugens maybe associated with the sex chromosome.2. Part of RAPD bands which were specific of a population were recovered, cloned, sequenced, and transformed to SCAR, only one specific band of TNI population was successful transformed, the band was about 410bp, the frequency was about 60%. Mudgo and ASD7 populations were tested about 100 individuals, no one had this band, only the TNI population had the band, so we concluded this band was TN1 population specific band, sequence homological compared to the Genebank, there was no higher homological.3. We got two relatively pure populations of TNI population by molecular selected, that was "had the specific band population" ("+/+" population) and "had no the specific band population" ("-/-" population). The two forms were reared on the susceptible varieties, and infested to the susceptible varieties, there was no significant difference in average weight gain, average honeydew excretion, but infested to resistant varieties, there was significant difference in average weight gain, average honeydew excretion and average longevity, the value of "+/+" form was above the value of "-/-" form. The two forms were reared on resistant varieties, and infested to the resistant varieties, Fl of two forms had no significant difference in average weight gain, average honeydew excretion, but the value of the "-/-" form was above the value of "+/+" form, F2 of two forms had significant difference in average weight gain, average honeydew excretion, perhaps the population composed by individuals that had more "-" marker, the population virulence would be stronger. The special band of TN1 population maybe link with avirulence, it was quality character confirmed by genetics experiment and tested by X2-test, followed 3:1 segregation ratio.4. The field population of N.lugens in FuYang district of HongZhou, the specific band had lower frequency was about 20% in field population, the frequency of experiment population was about 60%, but from 1997 to 2003, the frequency of TN1 population was less 40% in field population, so the frequency of the specific band was less 24% in field population, and the result was same.