The effect of foliar boron application on pollen performance in some plum cultivars

Flower samples were taken from boron-treated (B) and water-only (W) trees of Kebap, Angeleno and Black Diamond plum varieties in the collection garden of Aydın Adnan Menderes University, Faculty of Agriculture, Department of Horticulture in the spring of 2022. Boron and water applications were made to the plum varieties used in the experiment twice, one month apart, before the beginning of flowering. Boron was applied at 250 ppm per tree. In the pollen IKI viability test, the highest viability value (99.4%) was found in the boron-applied Kebap variety, and in the TTC viability test, the highest viability value (90.4%) was found in the boron-applied Angeleno variety. The highest flower pollen germination percentage was obtained in Kebap (W) variety with 64.5% on variety averages, and the highest value was obtained on 15% sucrose medium with 63.7% on sucrose averages. In the germination test performed using different boric acid concentrations in 10%sucrose medium, the highest germination rate was obtained in Kebap (W) variety with 71.5% on the variety averages, and the highest value according to the boric acid averages was obtained from the 0 ppm boric acid medium with 59.9%. In the germination test performed using different boric acid concentrations in 15% sucrose medium, the highest germination rate was obtained in the Kebap (W) variety with 89.9% on the variety averages, and the highest value according to the boric acid averages was obtained from the 100 ppm boric acid medium with 71.7%. The highest value in terms of average number of anthers in a flower was found in Black Diamond (W) variety, 27.04. The average number of pollen in a flower was determined in Kebap (W) variety with 8,500, and the highest value in terms of the average number of pollen in an anther was determined in the Angeleno (W) variety with 448.03. The highest value of pollen tube length in variety averages was obtained from Kebap (B) variety with 1,350.63 μm , and according to the boric acid averages, the highest value was obtained from 10% sucrose medium with 1,626.60 μm. In the germination test performed using different boric acid concentrations in 10% sucrose medium, the highest value of pollen tube length in variety averages was 1,441.3 μm in Kebap (W) variety, and according to boric acid averages, the highest value was 1,626.61 μm in 0 ppm boric acid medium, has been obtained. In the pollen germination test performed using different boric acid concentrations in 15% sucrose medium, the highest value of pollen tube length was in Kebap (B) variety with 1,951.56 μm on variety averages, and the highest value was 150 ppm boric acid with 1,684.67 μm on boric acid averages was obtained from the environment. Key Words: Plum, Boron application, Pollen germination, Pollen viability, Pollen tube lenght, Pollen production.