Abstract

Hawthorn is one of the most important medicinal plants with more nutrients, medical, ornamental and sanitary properties and used as a main dry tolerant rootstock recently. Commercial part of the hawthorn is its fruits and the most important factors involved in fruit set are pollination, pollen tube growth and fertilization. This study was carried out to investigate pollen germination and tube growth of some East-Azerbaijan, Iran indigenous hawthorn genotypes in differentin-vitro media for receiving the suitable medium for pollen germination and identifying favourable genotypes for using in the future breeding and orchard establishment programs. Experiment accomplished based on completely randomized design (CRD) in four repeats. Pollens gathered from anthers and maintained at refrigerator until usage. In-vitro medium has different concentrations of sucrose (5, 10, 15 and 20%), boric acid (0.005, 0.01 and 0.02%) with (1.2%) agar. Pollens were cultured in different media and maintained about 24 h in 22ËšC and then, their growth was stopped with raising cholorophorm. Finally, pollen germination percentage and tube growth were measured under light-microscope in 7 randomized selected squares. Results showed that the best in-vitro medium for hawthorn pollen germination and tube growth were composed of 15% sucrose, 0.005 - 0.01% boric acid and 1.2% agar and significant differences observed between various media in the studied pollen traits.

Key words: Hawthorn, Crataegus, pollen germination, pollen tube growth, in vitro medium.