The Effect of Self-Compatibility in Pollen Germination and Tube Growth in Almond

Although self-compatibility is a genetically qualitative trait in almond, its expression has been shown to be variable and dependent on the genotype. Thus, pollen germination and pollen tube growth were studied in the progenies of two different crosses, involving the same self-compatible female parent, 'Mardia' (S6Sf), and two self-incompatible male parents,'Desmayo Largueta' (S1S10) and 'Marcona' (S11S12). Pollen germination was tested following the Hermosa procedure and pollen tube growth was assessed in the lab after hand self-pollination of pistils following flower emasculation, pistil sampling after 96 hr and pollen tube growth observation by microscopic observation with fluorescence light. The results were statistically evaluated by variance analysis and the means were compared by the Duncan Multiple Range Test (DMRT). Results showed that pollen germination in an artificial medium was good for all progenies, with no significant differences between the individuals. Pollen tube growth, however, showed significant differences (5% level) between the styles of self compatible and self-incompatible seedlings. The observation of pollen tube growth after self-pollination allows not only the differentiation of the self-compatible plants and the determination of the phenotype frequencies, but also the establishment of the quality of the self-compatibility expression and the possible interest of each plant of the breeding program.