Publication Date

1989

Description

Field and glasshouse experiments indicate that several nematodes damage ryegrasses and white clover (Cook and York, 1985). Populations of these nematodes under grassland are often at potentially damaging densities. Several nematode species of long-term grassland have co-evolved host relationsh­ips in which host resistance is likely to have been selected. This is of direct practical relevance to the control of three nematodes, widespread in England and Wales: the root-knot nematode (Meloidogyne naasi) on ryegrasses; and the stem nematode (Ditylenchus dipsaci) and cyst nematode (Heterodera trifolii) on white clover. Our objectives have been, first, to identify resistant and susceptible phenotypes, and then to define the mechanisms of resistance and the genetics of plant reactions. Plants with defined and characterised reactions can then be used to assess the extent of variation in virulence in nematode populations, and the likely agricultural value of resistance. Progress in these studies is reported.

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Resistance to Plant Parasitic Nematodes in Ryegrasses and White Clover

Field and glasshouse experiments indicate that several nematodes damage ryegrasses and white clover (Cook and York, 1985). Populations of these nematodes under grassland are often at potentially damaging densities. Several nematode species of long-term grassland have co-evolved host relationsh­ips in which host resistance is likely to have been selected. This is of direct practical relevance to the control of three nematodes, widespread in England and Wales: the root-knot nematode (Meloidogyne naasi) on ryegrasses; and the stem nematode (Ditylenchus dipsaci) and cyst nematode (Heterodera trifolii) on white clover. Our objectives have been, first, to identify resistant and susceptible phenotypes, and then to define the mechanisms of resistance and the genetics of plant reactions. Plants with defined and characterised reactions can then be used to assess the extent of variation in virulence in nematode populations, and the likely agricultural value of resistance. Progress in these studies is reported.