Apricot breeding for multiple resistance to Plum pox virus and Apple chlorotic leaf spot virus

Spain is one of the most important producers of fresh apricots (Prunus armeniaca L.). Traditional production was based on several local cultivars with good quality and well adapted to the industry. However, most are sus-ceptible to important viral diseases that affect fruit production and quality. The main viral diseases are sharka (Plum pox virus, PPV) and viruela (Apple chlorotic leaf spot virus, ACLSV). Using foreign resistance sources to PPV, new resistant cultivars have been released. More recently, two new resistance sources to ACLSV have been identified: the Spanish cultivar 'Mauricio' and the French cultivar 'Bergeron'. With the objective of obtaining new genotypes resistant to both diseases simultaneously, two crosses between the apricot selections '5-26' and '11-1' from CEBAS-CSIC (resistant to PPV) and ACLSV-resistant cultivars 'Mauricio' and 'Bergeron' were ach-ieved, and the descendants were evaluated for resistance to these diseases. Molecular markers were also used to evaluate the genitors and descendants. Results showed that 100% and 75% of seedlings were resistant to PPV and ACLSV, respectively, and 70% were resistant to both diseases simultaneously. In general, no interaction between both viruses was detected, infecting the plant independently. For the first time, apricot plants resistant to PPV and ACLSV simultaneously have been obtained.