The definitive version is available at www.blackwell-synergy.comPollen competition and selection has significant evolutionary consequences, but very little is known on how they can be modulated. We have examined in cherry (Prunus avium L.) how pollen performance is affected by the genotype of the pollen and by the environmental conditions where it grows, namely the pistilar tissue and temperature. The different pollen donor genotypes tested in this work differed in their behaviour both in vitro and in vivo and this behavior was modulated depending on the female recipient were they grew. Furthermore, there was a significant temperature-genotype interaction that affected the pollen tube population census that succeeded to reach the base of the style. The combination of these three factors, while enabling a capacity of response to variations in environmental pressures, could maintain variability in pollen performance avoiding the fixation of the genes that control pollen tube growth rate.A. H. was supported by an AECI, SIA-DGA, and a CSIC fellowship. Financial support for this work was provided by project grants INIA-RTA 01-103, CICYT AGL2003-05318-C02-01 and by the “Grupo de Investigación Consolidado de Aragón”: A-02.Peer reviewed