Powdery Mildew Resistance in the Peach Cultivar Pamirskij 5 Is Genetically Linked with the Gr Gene for Leaf Color

Peach powdery mildew ( Podosphaera pannosa var. persicae ) is a major disease of peach trees [ Prunus persica (L.) Batsch]. Various studies on powdery mildew resistance have been conducted in peach. The present study was initiated to determine the inheritance of powdery mildew resistance found in the green leaf peach rootstock ‘Pamirskij 5’. Crosses were carried out between ‘Pamirskij 5’ and the susceptible red leaf peach rootstock ‘Rubira’®. Segregation analysis performed in F 1 (1:0), F 2 (3:1), and test cross (1:1) progenies indicated single dominant gene control of peach powdery mildew resistance in ‘Pamirskij 5’. Cosegregation analysis provided clear evidence that the loci for powdery mildew resistance and the leaf color trait are very closely linked in ‘Pamirskij 5’. The estimated distance between these loci was 0 ± 3.26 cM for the F 2 and 0 ± 0.00 cM for the test cross populations.