Effect of Sucrose and Boric Acid on in-vitro Pollen Germination of Guava (Psidium guajava) Varieties

The Premise of Research: To reproduce, higher plants utilize a unique multicellular microorganism: The male gametophyte, or pollen grain. It is known fact that pollen has a strong impact on physical and biochemical quality of fruit. Pollen germination and pollen tube growth are prerequisites for fertilization and seed development. Information about pollen germination will be helpful in the production of hybrids, which is an important step in a breeding program. In guava, such work on the pollen growth under the in-vitro condition is not clearly reported. So the aim of the study is to find the suitable media for in-vitro pollen germination of guava. Methodology: We used four different concentrations of sucrose and boric acid like 10%, 15%, 20% and 25% and 0.2, 0.4, 0.6, 0.8 g/l respectively. Using a brush, we evenly distributed the pollen over the culture medium in order to achieve the most homogeneous distribution of the material possible. After inoculation, the dishes were maintained in the dark at controlled temperature conditions (27±1ºC). These processes took place 2-4 h after inoculation, within the culture medium, by means of observation through a binocular stereomicroscope at 10× magnification. Results: The pollen germination was maximum 81.52% in Hissar Surkha at 10% sucrose solution and the boric acid concentration at 0.8 g/l shows the maximum germination rate (87.00%) in L-49 variety. The germination rate increases with increasing the boric acid concentrations. The boric acid concentration at 0.8 g/l shows the maximum germination rate (87.00%) in L-49 variety and the lowest was 75.73% in Kafri after three hours and with the same medium, highest pollen tube growth 42.25 µm in L-49 variety. Conclusion: The results suggest that the suitable media for pollen germination and pollen tube growth of guava under the in-vitro condition is boric acid (0.8 g/l) as well as sucrose (10%) solution.