Breeding for resistance: breeding for Plum pox virus resistant apricots (Prunus armeniaca L.) in the Czech Republic

Plum pox virus (PPV) causes serious damage in apricots grown in the Czech Republic and other countries where it is present. To study PPV resistance in apricot, three backcrosses between apricot cultivars or selection resistant to PPV and apricot cultivars or selections susceptible to PPV (‘LE3218’ × ‘Stark Early Orange’, ‘LE-3241’ × ‘Vestar’ and ‘LE-3246’ × ‘Vestar’) were performed. The seedlings were repeatedly inoculated with PPV-M strain by an infected chip. The resistance of the plants was evaluated by visual inspection for symptoms and ELISA in three consecutive growth periods. The Chi-square ( χ 2 ) test was used to analyse the data. It was found that two independent dominant complementary genes conditioned PPV resistance in apricot in the case of the backcrosses. The mode of inheritance for resistance to PPV in cv. Harlayne was determined from F1 progenies. Resistance to PPV in ‘Harlayne’ was controlled by three independent complementary dominant genes. This knowledge will help us in effective planning of apricot breeding programmes.