Fig. 2: Illustration of the different compatibility relationships observed using stigma tests in Ligustrum vulgare.

Each column (1–5) corresponds to a genotype used as the pollen donor on five recipient genotypes (rows A–E). Panels outlined in red correspond to self-pollinations. GA[SI] and GB[SI]: self-incompatible genotype belonging to the self-incompatibility groups A and B respectively; GA[SC] self-compatible genotype which stigmas are incompatible with pollen from GA genotypes. The scoring was binary, with “0” indicating incompatibility (absence of pollen tubes, or very short pollen tubes that do not reach the style) and “1” indicating compatibility (pollen tubes grow through the stigmatic tissue to the style and then toward the ovules).