Genetic studies of pea leaf‐roll (top‐yellows) virus resistance in <i>Pisum sativum</i>

Abstract

Abstract Six pea cultivars and their F 1 and F 2 progenies were assessed for resistance to pea leaf‐roll (top‐yellows) virus infection under natural epidemic conditions. Two cultivars were highly resistant, two moderately resistant, and two highly susceptible; all F 1 and the majority of F 2 hybrids between any two cultivars showed a lower mean resistance than the better of the two parents. Resistance to infection was controlled by an additive system of inheritance, with “moderate” resistance being dominant to both susceptibility and high resistance. The effect of disease on components of yield was also shown to be inherited in a quantitative manner, but no hybrid combination exhibited high economic value for all characters. The effect of top‐yellows infection on yield in the New Zealand pea experiment was similar to that on infected field beans in England.