In vitro pollen germination of Argan (Argania spinosa (L.) Skeels)

An easy and reproducible pollen germination method for Argan (Argania spinosa (L.) Skeels) has been established using a combination of three phenological phases (flower bud BF, flower bud with an emerging style BFS and blooming flower FE), two germination media, two incubation temperatures (25 degreesC and 30 degreesC) and 14 genotypes. The number of germinated pollen and the pollen tube growth were observed. Best results were obtained with pollen extracted from FE on a solid 1% agar medium containing 20% sucrose, 200 ppm CaCl2 and 75 ppm H3BO3, at 30 degreesC for a minimum of 20 h, while sustainable tube growth was maintained until the end of the experience. The pollen from BF phase does not germinate at all. The germination of the pollen from BFS, although low, was dependent on the genotype. Thus, emasculation is requested at early BF stages to avoid self-pollination prior to hand pollination. Highly significant differences between tree genotypes was observed for the number of germinated pollen and for tube growth showing a differential male-gametophytes potential fitness that could influence gene flow between trees.