ROOTSTOCK BREEDING PROGRAMME FOR APRICOT THROUGH INTERSPECIFIC CROSSES OF MYROBALAN X APRICOT: SIGNIFICANT EFFECT OF ACCIDENTAL POLLINATIONS

A rootstock breeding programme for apricot is being developed through interspecific crosses of the Myrobalan plum (Prunus cerasifera Ehrh.) and the ‘Moniquí’ and ‘Moniquí Borde’ (P. armeniaca L.) apricot cultivars. In this work, the incidence of accidental pollinations on these low-setting hybridisations was assessed. The progeny originated through hand-pollination of emasculated flowers of three Myrobalan clones, in three consecutive years. Fruit set was low and variable among years (1.8-8.0%), but higher than the level of accidental pollination measured with emasculated and non-pollinated flowers (1.2%). The molecular characterisation of the progeny was performed with three SSR markers. The results show that, from the 278 genotypes evaluated, 73 appeared to be hybrids and 205 did not. The procedure to obtain hybrid plants is discussed here in terms of the loss of hybrid clones along the process from pollination to field cultivation.