Utility of wild germplasm in olive breeding

Olive breeding programs are only based on commercial cultivars as genitors. However, due to its wide variability, wild olive gremplasm could represent an interesting source of genes for the obtention of new cultivars. With purpose of evaluating the utility of wild olives in breeding programs, two open pollinated progenies (o.p.), originated from a wild olive (Alga05) and the main Spanish olive cultivar (Picual), were compared. Both progenies were analyzed by morphological descriptors, agronomical traits and SSR markers. The use of these 3 marker systems revealed great discrimination capacity, high level of morpho-agronomic and genetic diversity and their complementariness on the evaluation of these olive progenies. As expected, for most of morpho-agronomical traits, ‘Picual’ o.p. progeny showed superior values in comparison to the wild o.p. progeny. However, ‘Alga05′ wild olive progeny was more vigorous, with shorter juvenile period and more abundant flowering than ‘Picual’ o.p. For both progenies, PCA showed strong association between different agro-morphological traits (fruit and stone dimensions in wild olive progeny and fruit trait with oil content in ‘Picual’ progeny) which could facilitate the selection of the most appropriate traits for further evaluations, increasing thus, the efficiency of olive breeding programs. Our results indicate that the use of wild olive as genitors in breeding programs may be useful for generating new genotypes with interesting characters.

► High morphological variability and genetic diversity obtained by open pollination in olive.
► Morphological, agronomical and molecular variability are complementary in olive.
► Wild olive progeny seedlings showed higher vigor, abundant flowering and shorter juvenile period than cultivated olive progeny seedlings.
► Further crosses between wild and cultivated germplasm could be of interest for olive breeding programs.