GENETIC STUDY ON RESISTANCE TO POWDERY MILDEW IN STRAWBERRY

Three hundred and twenty seven F1 clones from a cross combination of resistant cultivar ‘Sweet Charlie’ and susceptible cultivar ‘Toyonoka’ were used to analyze the genetic model of resistance to powdery mildew in strawberry. The disease classes of F₁ clones in both leaf and fruit showed continuous distribution, indicating that the powdery mildew resistance was controlled by multiple genes. The broad sense heritability of leaf and fruit resistance was 68 and 66%, and the dominant degree of susceptibility was -0.15 and -0.16 in leaf and fruit respectively. The correlation coefficient between the leaf and fruit disease class was 0.5795, which was significant at 0.01 probability level, while the correlation coefficients between the disease class and fruit weight, length, width, soluble solid content were not significant.