Resistance to cane spot (Elsinoë veneta) in the red raspberry and its relationship to resistance to yellow rust (Phragmidium rubi-idaei)

Summary Varying degrees of resistance to cane spot were recorded among red raspberries in two cultivar trials and in 15 segregating families. The inheritance of resistance was studied, and the effect of gene H which determines the presence of cane hairs was assessed in eight of the families. The 0 to 5 scale used to record disease incidence was found to approximate to a logarithmic scale for the range of 0 to 93 cane spots per cane. Gene H and h phenotypes averaged scores of 3.05 and 2.42 respectively, but other genes independent of these had more influence on resistance. The latter genes appeared to be largely dominant. The possibility is discussed that one of them was a major gene with a large effect, but the evidence was equivocal in the absence of discontinuity in the expression of resistance. Resistance to yellow rust was studied in five of the families and was highly correlated with resistance to cane spot. Gene H had more influence on this disease, the mean counts of telia per unit leaf area for H and h segregates being 17.1 and 4.1 respectively.