Determination of the effects of growth regulators on pollen viability and germination level of tulip

The present study was focused on determining the effects of brassinosteroid, naphthalene acetic acid and gibberellic acid on in vitro pollen germination and pollen viability of tulip. Knowledge on different sources of pollen is an important issue for ornamental plant growers or breeders especially in crossing procedures for tulip. Flower bud formation and inflorescence is affected by bulb size, environment, irrigation, nutrition and many other factors. In some ornamental plants pollen quality as well as cultivar affect viability and germination characteristics. Tulipa greigii 'Pinocchio' was used as a pollen source which was tested for its ability to germinate in vitro on a medium (1% agar and 20% sucrose) containing three different group of hormones, gibberellic acid (GA₃), naphthalene acetic acid (NAA) and epibrassinolide (EBR). After 24 h of incubation, pollen were evaluated and germination ratios were determined. The results indicate that pollen germination was significantly affected by growth regulators while pollen viability and germination rates were altered according to the concentrations and the type of the growth regulators. The highest average value of the pollen germination rate (42.95%) was determined in the concentration of 0.1 mg L^‑1 EBR treatment in Tulipa greigii 'Pinocchio', while the highest value (92.47%) for the pollen viability was obtained from epibrassinolide (EBR) in comparison to the other hormones.