**7. Paternity analysis**

Similar to other woody species, olive is characterized by a long juvenile phase that ranges between 10 and 15 years. This represents a great obstacle to breeding programs and makes the genetic improvement of olive very difficult and expensive. Although seedling-forcing growth protocols have been developed to reduce the length of this phase, the evaluation of the agronomic performance of mature olive plants still requires at least 5 years of experimentation (Santos-Antunes et al. 2005). For this reason, the application of molecular markers both to confirm the parental origins of the progeny and to select early agronomical characteristic-associated markers (Mart´n et al. 2005) can be very useful to reduce the time and cost of the development of new genotypes (Bracci et al., 2011).

With regard the paternity analysis, SSRs are the most suitable to trace the genetic contribution of alleles from the parents to the offspring, being co-dominant and highly polymorphic markers (Mookerjee et al. 2005). The effectiveness of SSRs in the identification of paternity contribution to progeny obtained from olive breeding programs has been demonstrated by several authors (De la Rosa et al. 2004; Diaz et al. 2007). The results demonstrated that SSR analysis is a convenient technique to routinely assess the crosses made in breeding programs and to for check self-incompatibility in olive cultivars (Diaz et al. 2006). These studies have highlighted that no contamination by self-pollen was found, indicating that placing pollination bags well before anthesis is important and that emasculation to avoid selfing is unnecessary (De la Rosa et al. 2004). The analysis also revealed that the main factor affecting the success of crosses seems to be the intercompatibility among the parental cultivars, since this significantly influences the rate of contamination from external pollen donors. These results indicate that knowledge of crosscompatibility among cultivars is necessary to plan efficient olive breeding crosses (Diaz et al. 2007).

The possibility of associating genetic characteristics and DNA-based molecular markers is very important to select the progeny showing interesting agronomical traits and even specific organoleptic characteristics at the first stages of development which may use as a marker for future *olive oil* identification. However, this technique, called marker-assisted selection (MAS), requires some knowledge on the co-segregation of molecular markers and genetic characteristics in the progeny. (Bracci et al., 2011)
