Identification of genetic markers in olive linked to olive leaf spot resistance and susceptibility

Olive leaf spot is a disease of olive (Olea europaea L.) caused by the fung al pathogen, Spilocea oleaginea Cast. Progeny derived from crosses among su sceptible, resistant, and semiresistant parental lines were assessed in the field for 8 years and classified as either resistant or susceptible. DNA f rom some of the progeny of this segregating population was used to identify molecular markers linked to olive leaf spot disease using the randomly amp lified polymorphic DNA (RAPD) technique and bulked segregant analysis (BSA) . Two DNA bulks were constructed, each containing 13 progeny showing either resistance or susceptibility for the disease, and screened for polymorphis ms using 100 primers. One primer produced two polymorphic bands, one of app roximate to 700 base pairs (bp) from the susceptible bulk and the other of approximate to 780 bp from the resistant bulk. The 780 bp marker appeared i n 70.6% of the segregating progeny and 100 % of parents showing resistance to leaf spot disease, while the 700 bp marker appeared in 47.1% of the segr egating progeny and 100% of the parents showing susceptibility. These marke rs can be used as screening tools in olive improvement programs.