The effect of genotype and temperature on pollen tube growth and fertilization in sweet cherry (Prunus avium L.)

The study of pollen performance in vivo of four self-incompatible sweet cherry cultivars-'Karina', 'Kordia', 'Regina' and 'Summit' was performed. The results were considered in the context of climatic conditions of West Serbia, bearing in mind increased frequency of seasons with higher temperatures during the flowering. Each cultivar was used as polleniser and pollinated cultivar, and together with the open pollination variant, a total of 16 combinations were analysed during the three-year period. The effect of variability factors on pollen tube growth efficiency occurred as a common impact of polleniser, its requirement to flowering temperatures, the influence of pollinated cultivar on pollen performance, and the response of male-female relations to air temperature. 'Summit' induced the highest pollen tube number, while the pollen tube number of 'Kordia' was the lowest. Higher temperatures during the flowering have caused a decrease in the number of pollen tubes in 'Kordia' and 'Karina', and increase of their number in 'Regina' and 'Summit' as pollenisers. The genotype-dependent response of pollenisers in terms of air temperature during the flowering has not consistently manifested, and was partially modified by the influence of the pollinated cultivar. The main tendencies were more apparent in the 'borderline cases', i.e. in pollination of cultivars having diametrically opposite requirements, than in those of cultivars having similar requirements regarding the flowering temperature