The Viability of Pollen from Natural Populations of Pinus brutia var. pityusa (Steven) Silba in the Mountainous Crimea

Pollen quality indicators are the most important characteristics of the development of male generative structures. For species of the genus Pinus L., a quantitative assessment of the effectiveness of the development of the male generative sphere is of great importance, since the first, most important stages of seed formation are directly related to the volume of pollen produced by plantings and the level of its viability. The research has been carried out in natural populations of P. brutia var. pityusa of the Mountainous Crimea. To collect pollen samples and study its quality, test plots have been laid for 4 hypsometric profiles in the western part of the southern macroslope of the main ridge of the Crimean Mountains on Cape Aya, in the Ayazma and Batiliman Mountain Areas and in the eastern part – on Karaul-Oba Mount and in the Novyj Svet Mountain Area. Pollen has been collected from 10 model trees in the test plots during its free flight period. It has been established that the pollen of P. brutia var. pityusa, which grows in the western part of the mountainous Crimea, has a higher quality compared to the pollen of trees in the eastern territories. In the eastern part, there is also an increase in the number of anomalies in the size and shape of pollen grains, which is associated with deterioration in the temperature regime during the period of microsporogenesis. The study of pollen properties using the germination method on an artificial nutrient medium has revealed a decrease in the level of viability of pollen compared to the results of acetocarmine testing; the differences have been 4–9 %. Meanwhile, the highest level of pollen germination has been observed in the plantations of the upper part of the tract – the average value has been 89.9 ± 2.5 %, for the central and lower parts it has been 88.1 ± 2.7 and 87.9 ± 3.5 %, respectively. The combined use of 2 methods to assess the viability of pollen made it possible to propose a new indicator of its quality – the index of realization of the male gametophyte at the stage of pollen germination. This approach has allowed us to establish that the lowest index is characteristic of the plantations of the central part of the forest tract of the Ayazma Mountain Area – 0.911.