Pollen Tube Growth in Cross- and Self-pollinated ‘Nonpareil’ Almond

Abstract

Abstract Investigation of pollen grain germination and retention on the stigma, and pollen tube frequency in the style following compatible (cross) and incompatible (self) pollinations in ‘Nonpareil’ almond [ Prunus dulcis (Mill.) D.A. Webb Syn. Prunus amygdalus Batsch.J revealed that rejection of incompatible male gametophytes occurs on the stigma as well as in the style. Self-pollinations are characterized by lower pollen grain retention on the stigma, reduced and delayed pollen germination, and, where pollen germination had occurred, a low frequency of pollen tubes growing through the style. Pollen tube growth slowed greatly after the tubes entered the ovarian locule before they reached the ovule.