Paternity analysis using microsatellite markers to identify pollen donors in an olive grove

Abstract

Olive (Olea europaea L.) is a wind-pollinated, allogamous species that is generally not considered to be self-compatible. In addition, cross-incompatibilities exist between cultivars that can result in low fruit set if compatible pollinisers are not planted nearby. In this study, microsatellite markers were used to identify 17 genotypes that were potential pollen donors in a commercial olive orchard. DNA typing with the same primers was also applied to 800 olive embryos collected from five cultivars in the grove over 2 years of study. Pollen donors for the cultivars Barnea, Corregiola, Kalamata, Koroneiki, and Mission were estimated by paternity analysis, based on the parental contribution of alleles in the genotypes of the embryos. The exclusion probability for the marker set was 0.998 and paternity was assigned on the basis of the 'most likely method'. Different pollen donors were identified for each of the maternal cultivars indicating that cross-compatibilities and incompatibilities varied between the genotypes studied. Cross-pollination was the principal method of fertilization, as selfing was only observed in two of the embryos studied and both of these were from the cultivar Mission. This is the first report where these techniques have been applied to survey the pollination patterns in an olive grove. The results indicate that careful planning in orchard design is required for efficient pollination between olive cultivars.

Sexual compatibility and floral biology of some olive cultivars

“…Under the environmental conditions of this study, 'Frantoio' was self-incompatible (IPI0 0.00), which agrees with the findings of Wu et al (2002) and Mookerjee et al (2005), while it was previously recorded as self-compatible in Australia (Sharma et al 1976) and in some other countries (Fontanazza & Baldoni 1990;Fabbri et al 2004). 'Frantoio' (as a host) was also crossincompatible with 'Barnea' and 'Koroneiki' but partially compatible with 'Mission'.…”

“…The same result was also obtained by Mookerjee et al (2005) in South Australia. Results from the present study showed that 'Koroneiki' (as a host) was incompatible with 'Barnea' and partially compatible with 'Frantoio' and 'Mission' while Mookerjee et al (2005) found incompatibility between 'Koroneiki' (as a host) and 'Frantoio'. They also observed that 'Mission' was the best pollen donor for 'Koroneiki'.…”

“…Crossincompatibility between olive cultivars has previously been suggested by many authors (Griggs et al 1975;, although Lavee et al (2002) did not find any true cross-incompatibility after their long-term (12 years) and large-scale (36 cultivars at three sites) experiment. Cross-incompatibility between 'Frantoio' (as a host) and 'Barnea' has also been observed using paternity analysis (Mookerjee et al 2005), another technique to evaluate pollen incompatibility.…”

Traceability of Origin and Authenticity of Olive Oil

“…In Olea europaea, these markers have been used for different applications such as cultivar discrimination (Sarri et al 2006;Fendri et al 2010), study of relationships between wild and cultivated olive tree (Belaj et al 2007), construction of association maps (De la Rosa et al 2003), paternity analysis (Mookerjee et al 2005) and identification of olive oil varietal composition (Alba et al 2009;Ayed et al 2009;Rabiei et al 2010). A list of recommended SSR markers and protocols for olive genotyping has been provided with the aim to develop a robust method to track the origin of olive cultivars (Doveri et al 2008;Baldoni et al 2009 Table 4.…”

“…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).…”