Field trials using single potato plants as whole plots, with and without nematicide treatment, to assess tolerance of attack by Globodera rostochiensis

Abstract

It is important to assess the tolerance of new potato cultivars with partial resistance to potato cyst nematode attack. The experiments described here are intended to quantify tolerance adequately using a minimum of resources. When test plants were spaced widely in the field trials it was also possible to estimate their resistance levels but standard plant spacing allowed roots of neighbouring plants t o encroach on a test plant's root space and to interfere with attempts to assay resistance. Standard plant spacing did, however, give more realistic yields per plant and competition from neighbouring plants was standardised by surrounding each test plant by four identical guard plants (cv. Desiree). Regressions of yield on severity of nematode attack were drawn when nematode infestation varied naturally across the trial site or when different levels of attack were created by applying nematicide at a range of dose rates. Cara was the most tolerant cultivar tested, with a complete spectrum of tolerance shown by other cultivars/clones. Some clones with a high degree of resistance were intolerant and it is precisely these that this type of test seeks to identify.

Relationship between potato cyst nematodes and their principal host. III. Consistency and accuracy of nematode density — yield descriptors as influenced by seasonal variation

“…Hence, the potential production level for a certain year has no bearing on the test for tolerance in the field. This is in agreement with results of Evans & Russell (1990). …”

Relationship between Yield Potential and Percentage Yield Suppression Caused by the Southern Root‐Knot Nematode in Cotton

“…Behrens included two susceptible standards, ‘Pentland Dell’ and ‘Désirée’. Désirée had a higher yield potential and suffered a greater percentage yield loss than Pentland Dell (Evans and Russell, 1990). It is more difficult to interpret the results of some studies.…”