<i>In Vitro</i> Pollen Germination Testing for Controlled Pollination Success in Shea Tree (<i>Vitellaria paradoxa</i> Subsp. <i>paradoxa</i>)

In order to better plan controlled pollination conducted by the shea tree improvement program of Côte d’Ivoire hosted at Peleforo Gon Coulibaly University (UPGC, Korhogo), a study was carried out to optimize the in vitro germination tests of shea tree pollen. Two successive experiments were conducted at the UPGC laboratory of the African Centre for Shea Research and Applications (CRAK). The first experiment aimed to determine the most suitable culture medium composition for optimal in vitro germination of shea pollen. Four media coded as M1 (10 g sucrose, 1.5 g agar, 100 ml distilled water), M2 (10 g sucrose, 0.6 g agar, 100 ml distilled water), M3 (20 g sucrose, 0.6 g agar, 100 ml distilled water), and M4 (9 g sucrose, 0 g agar, 100 ml distilled water) commonly used for forest tree species were tested with four incubation durations (5, 10, 30, and 48 hours) at 30˚C. The second experiment aimed to identify the optimal temperature for pollen germination. Five temperature conditions were tested: 25˚C, 30˚C, 35˚C, 40˚C, and ambient temperature (29˚C - 37˚C). The results showed culture media M1 (10 g sucrose, 1.5 g agar) and M2 (10 g sucrose, 0.6 g agar) gave the highest in vitro pollen germination rate (75.73%) after 30 hours of incubation. Heat significantly influenced the in vitro germination capacity of shea pollen. Based on these findings, the Shea Tree Improvement Program of Côte d’Ivoire can now assess pollen viability using a gel-based medium with 10 g sucrose and either 0.6 g or 1.5 g agar, incubated for 30 hours at a temperature ranging from 25˚C to ambient conditions (29˚C - 37˚C).