POLLEN GERMINATION OF THE WALNUT CULTIVAR‛GEISENHEIM 286’ ON DIFFERENT CULTURE MEDIA

Pollen of the walnut cultivar ‛Geisenheim 286’ was cultured on germination media containing all possible combinations of sucrose (10, 15 and 20%); agar (0.6 and 0.8%); boric acid (0, 300 and 600 ppm) and calcium chloride (0, 50 and 100 ppm). A total of 54 different combinations of germination media were tested in an attempt to establish a suitable culture media for studying in vitro pollen germinability of the walnut. Significant differences in pollen germination were observed in response to changing concentrations of sucrose, boric acid and calcium chloride, but germination was not affected by changes in agar concentration. The interactions of the concentrations of agar and calcium chloride, boric acid and sucrose, calcium chloride and sucrose, as well as those of boric acid, calcium chloride and sucrose were significant. Pollen germination was maximized (27.8%) when the germination medium contained 0.8% of agar, 15% of sucrose, 600 ppm of boric acid and 50 ppm of calcium chloride.