POLLEN VIABILITY AND GERMINABILITY OF WALNUT: A COMPARISON BETWEEN STORAGE AT COLD AND ROOM TEMPERATURES

Pollination is an important practice in the management of walnut orchards. The optimization of pollination is required for a profitable yield. Achieving success in walnut production requires an awareness of pollen viability and germinability, in addition to selecting the right pollinators. Here, the pollen viability and germinability of 'Maraş 18', 'Diriliş', 'Bayrak' and 'Sütyemez 1' walnut cultivars were evaluated following storage at cold (4°C) or room temperature (23°C) for 10 weeks. Pollen viability and pollen germination were examined by 2,3,5-triphenyl tetrazolium chloride (TTC), fluorescein diacetate (FDA), 'Agar in petri' and 'Hanging drop' tests, respectively. Neither the cultivars nor the tests exhibited a significant difference with regard to either pollen viability or germinability. However, the storage temperature affected both parameters. Pollen stored at 4°C maintained their pollen viability and germination rate for longer periods compared to pollen stored at 23°C. The results indicate that walnut pollen can be stored at room temperature and then be used optimally if the storage period does not exceed 1 to 2 weeks, whereas cold storage can provide a higher viability rate and a longer storage time, if necessary.