HEREDITY OF THE RESISTANCE TO LEAF CURL (TAPHRINA DEFORMANS) AND GREEN APHID (MYZUS PERSICAE) IN THE PEACH

The peach rootstock GF 305 resistant to Leaf Curl, was crossed with a susceptible variety S 763. The F₁ family showed an intermediate resistance and the F₂ gave a Gaussian distribution. These results agree with a polygenic inheritance.

In the case of Green Aphid resistance, we have chosen the parent S 2678, among different sources of resistance. Two self pollination offsprings of this tree both resistants to Green Aphid, were crossed with S 1161:12 susceptible and originated from a Redhaven self pollination.

The F₁ family of this cross showed a total resistance and the F₂ gives a clear-cut ratio : 3–1.

The Green Aphid resistance is dominant and determined by one gene.