Pollination is very important to obtain economical yield in hazelnut. The selection of pollinizer with suitable quality and quantity of pollen is an essential practice in hazelnut orchards. In this research, the effect of different pollinizers (Kalibar8, Kalibar11, Long d’Espagne and Merveille de Bollwiller) was compared on nut and kernel development and quality of four commercial hazelnut cultivars (Rond, Segorbe, Fertile de Coutard, Negret). Result showed that the percentage of pollen germination was more than 60% for all cultivars at the time of application, indicated that all studied cultivars have high viable pollen ratio and pollen germination capacities. The dichogamy type in the selected cultivars was all the same, and protandry was common. The considered cultivars had significant differences in blooming time; so that flowering time for male flowers varied from January 28 to March 05, and for female flowers ranged between February 10 and March 08. After fruit harvesting, nut and kernel traits were evaluated. The cross-pollination with the pollen of different pollinizers had significant effect on increasing values of final fruit setting, nut and kernel weight and kernel percentage, with decreasing blank nuts in all pollinated cultivars. While, self-pollination reduced values of nut and kernel traits and increased percentage of blank nuts. It was concluded that the pollen sources had xenia and metaxenia effects in hazelnut
