Morpho-biological features of oriental persimmon pollen

It is known that a large number of persimmon cultivars are characterized by parthenocarp; however, the palatability of the fruit improves, and the yield increases significantly with cross-pollination. The main aim of this research is to study the viability of pollen of polygamous persimmon genotypes and to determine the ratio of normally developed and giant pollen grains in the analyzed samples. The study of the results of the structural features for the pollen of five persimmon cultivars of the Nikita Botanical Gardens selection (Yuzhnaya Krasavitsa, Yaltinskaya, Mechta, Prelestnaya, Zolotistaya) growing in the gene collection, which is located in the soil and climatic conditions of the Southern coast of the Crimea, made it possible to reveal a significant difference between the degree of germination of pollen grains. On an artificial environment containing 20% aqueous solution of sucrose, the maximum level of this indicator was recorded for the ‘Yuzhnaya Krasavitsa’ cultivar – 33.7%, and the minimum – 21.5% for ‘Zolotistaya’. A similar tendency is observed in the process of germination of grains and the formation of pollen tubes on a medium with 15% sucrose solution: ‘Yuzhnaya Krasavitsa’ – 22.4% (maximum), ‘Zolotistaya’ – 21.5% (minimum). Depending on the genotype, the diameter of pollen grains varies from 29.73 μm (‘Yuzhnaya Krasavitsa’) to 68.13 μm (‘Yaltinskaya’). In the pollen samples of four genotypes, giant grains were found: ‘Yalta’ – 8.0%, ‘Mechta’ – 7.9%, ‘Prelestnaya’ – 9.8%, ‘Zolotistaya’ – 15.4%. On the basis of the obtained results, diagrams were constructed that reflect the specifics of the distribution of pollen grains depending on their diameter. The use of the analyzed persimmon genotypes as pollinators is not effective due to the low degree of viability of the pollen that they form. The presence of unreduced pollen (giant grains) in the cultivars ‘Yaltinskaya’, ‘Mechta’, ‘Prelestnaya’ and ‘Zolotistaya’ allows them to be used in the breeding process to obtain new polyploidy seedless hybrids.