In the present work it was studied features associated to the germination of pollen and the development of pollen tubes in six apple varieties as subsidies for the establishment of genetic improvement programs. Pollen grains were inoculated in culture medium with distilled water, agar (10 g. L-1), combined with sucrose at 0, 10, 20, 30, 40 and 50% and boric acid at 0 and 40 mg. L-1. For the study of pollen tubes development flowers were collected at 6, 12, 24 and 48 hours after antesis in M.9 x Marubakaido and in the self-pollinated M.9, being the pollen tubes analyzed in staining with blue aniline with acetic carmim and in fluorescence. Sucrose in concentrations ranging from 15% to 25% can successfully be used for the in vitro germination of pollen grains. Boric acid was not effective in promoting in vitro germination of pollen grains. In the absence of boric acid and in the presence of 15% of sucrose it was observed the largest germination rates: Fuji (51.1%), Imperatriz (31.7%), M.9 (20.8%), Catarina (19.2%), Gala (13.7%), and Marubakaido (6.1%). In the crossing M.9 x Marubakaido after 12 hours of pollination the pollen germination began in the stigma and after 24hrs it was observed 83% of germination. The techniques employed were efficient in the visualization and coloration of the pollen grains and of development of tube pollen.
Malus sp.; pollen; sucrose; fluorescence
