A Dual-Successive-Screen Model at Pollen/Stigma and Pollen Tube/Ovary Explaining Paradoxical Self-Incompatibility Diagnosis in the Olive Tree-An Interpretative Update of the Literature.

The 'pollen test' and 'fruit set test' following controlled crossing combinations of parents are the most commonly used methods for pollination incompatibility studies in . Self-incompatibility (SI), with diagnoses based on the pollen test and pollen germination, indicating self-compatibility, is not always followed by fruit set in this species. To solve this dispute, we have reconciled all observations into a new model.

Reply to Saumitou-Laprade et al. (2017) "Controlling for genetic identity of varieties, pollen contamination and stigma receptivity is essential to characterize the self-incompatibility system of L.". Eva:https://doi.org/10.1111/eva.12498.

This study was carried out to examine the validity of previous studies on the intercompatibility of olive and to compare the approach and techniques used for proposing the diallelic self-incompatibility system and the sporophytic self-incompatibility system. Analysis of the literature indicates that the mating system of the olive tree is a controversial issue and requires further studies to clearly and fully comprehend it. All possible approaches should be used to maximize reliability of the final conclusions on the olive mating system.

'Comment on Saumitou et al. (2017): Elucidation of the genetic architecture of self-incompatibility in olive: evolutionary consequences and perspectives for orchard management'.

The new self-incompatibility system (SI) was presented by Saumitou-Laprade, Vernet, Vekemans et al. (2017). based on 89 crosses between varieties in the olive tree.

New hypothesis elucidates self-incompatibility in the olive tree regarding S-alleles dominance relationships as in the sporophytic model.

Most olive varieties are not strictly self-incompatible, nevertheless, they request foreign pollen to enhance fruit yield, and consequently orchards should contain pollinisers to ensure fruit set of the main variety. The best way to choose pollinisers is to experiment numerous crosses in a diallel design. Here, the genetic mode of inheritance of SI in the olive is deciphered and it does not correspond to the GSI type, but to the SSI type.

The origins of the domestication of the olive tree.

The present diversity of the olive (crop) and oleaster (wild) tree was investigated with nuclear and cytoplasm markers. Patterns of diversity of the wild form inferred eleven ancestral populations in the East and the West of the Mediterranean basin. Patterns of diversity for cultivars are less clear, but we showed that cultivars admixed to nine groups that corresponded to oleaster ancestral populations.