Effect of plant growth regulators on in vitro pollen germination of grapevine cultivars

In the present report the effects of naphthalene acetic acid (NAA), gibberellic acid (GA₃), and epibrassinolide (EBr) on in vitro pollen germination of three Vitis vinifera L. cultivars were described. The basic media contained 1% agar and 20% sucrose. Pollen germination of cultivar 'Amasya Beyazı' was not affected by the treatments and the germination rate varied between 6.16% (1.0 mg L^-1 NAA) and 35.98% (50 mg L^-1 GA₃). The stimulating effect of GA₃ and EBr was noticeable in cultivar 'Müşküle'. Concentration of 25 mg L^-1 GA₃ had the highest effect on increasing of the pollen germination of cultivar 'Kozak Beyazı' compared to the NAA, epibrassinolide and the control. The results showed that the response of the pollen grains were cultivar specific and substance specific. In general, NAA was the growth regulator that least enhanced the germination of grapevine pollen.