Optimization of Conditions for In vitro Pollen Germination and Tube Growth in Potatoes

Abstract

We have optimized the in vitro conditions for germination and tube growth of potato pollen, primarily that of tetraploid cv. Borka, in suspension culture under constant aeration and pollen density. Optimal concentration of H3BO3 and sucrose were 0.8 mM to 3.2 mM and 15%, respectively. Lactose and polyethyleneglycol (PEG 1000) were superior to sucrose in promoting pollen germination and tube growth, while substitution of sucrose with raffinose, maltose, glucose, galactose, fructose, or mannitol did not improve medium for germination. The best results were achieved with 20% PEG 1000 and 2% sucrose at 1.6 mM H3BO3. The superiority of the PEG medium was confirmed in three dihaploid genotypes. Calcium nitrate at 0.1 and 1 mM inhibited pollen germination and tube growth, and the inhibitory effect on germination was much stronger with sucrose than with PEG. No differences were found in germination rates and tube growth at pollen densities 0.5 and 1.5 mg mL-1 but increasing the density to 3 mg mL-1 reduced germin...