vasinfectum collected from Shache county, Xinjiang was tested to be 100,while the CI between them and each of the other three forma specialises was 0, which belong to different vegetative compatibility groups(VCGs).

Studies on the vegetative compatibility of pathogenic Fusarium oxysporum:;

Twenty strains of Fusarium oxysporum isolated from cucumber,melon and watermelon were grouped into vegetative compatibility groups(VCGs)by using nitrate nonutilizing(nit)mutants,and dif-ferent percentages of chlorate resistant mutant and nit mutant obtained from different hosts,positions of the plant and pathogenicity were observed.

Trophic groups of soil nematodes were investigated in the rhizosphere and non-rhizosphere of Vetiveria spp.

After 4 months nematode inoculation,4 families and 7 genera of nematodes were identified in the MSW compost medium,which belonged to three trophic groups,namely plant-parasites,fungivores and bacterivores.

The 111 076 nematode individuls were classified into 43 genera and 4 trophic groups.

Total nematodes populations and trophic groups seasonal dynamics,soil layer distribution,and as well as the effects of nitrogen fertilisation on soil nematodes were investigated in ash (Fraxinus mandshurica) and larch(Larix gmelinii) plantations,which grow in the similar sites, during 2007 and 2008.