Biochemical genetics of powdery mildew resistance in pea.

A biochemical study on phenolic (total phenols and orthodihydroxy phenols) content and on the activities of phenol oxidizing enzymes (peroxidase and polyphenol oxidase) in pea cultivars resistant and susceptible to powdery mildew infection revealed that the resistant cultivars contained higher levels of phenolics and phenol-oxidizing enzymes than the susceptible ones. A further study of their F1s, F2s and backcross progenies suggested a high heritability for all biochemical traits. The correlation coefficients between the biochemical parameters and the disease index were also high. Both additive (d) and dominant (ĥ) components were found to contribute to the inheritance of these constituents.