An investigation of the susceptibility of varieties of lucerne, Medicago sativa L., to the nematode Ditylenchus dipsaci (Kuhn)

Abstract

The results of testing lucerne for resistance to the stem nematode Ditylenchus dipsaci are recorded. A major part of the study was given to perfecting a technique for growing lucerne seedlings for inoculation with nematodes. Two techniques were tried and filter paper rolls were found to be superior to soil flats.

The technique of growing seedlings in filter paper rolls and inoculating them with nematodes was used to produce a rating of the resistance for the New Zealand variety of lucerne, Wairau, when compared with a known resistant variety, Washoe and a susceptible variety, Grimm. From the results obtained Wairau must be classified as a susceptible variety.

It appears that a selection within a variety of lucerne for resistance to Ditylenchus dipsaci could be made by eliminating the swollen plants. However, to obtain the relative resistances of several varieties, it would be necessary to obtain a measure of the reproductive rates of the nematodes in the plants.