This research was conducted in Kamal-Shahr Research Station during 1381-82 to evaluate the percentage of dicogamy, self-compatibility, and to select the best pollinizer for commercial varieties of hazelnut. Four trees of different varieties were selected for which some traits such as flower characteristics, type of flowering, pollination and fruit set were determined during the growing season. Pollination and fruit setting indicated that most varieties were cross pollinate, and some self pollen pollinated, and catking, so the rate of fruit set in isolated flowers is significantly different than in open pollinated ones. Fruit set in isolated flower as against open pollinated in varieties of Gerge, Gerdoii, Rasmi, Pashmineh, Fertil du cutard, Round du pimon, Negret, Paizeh and Shastak-2 was 5.8 & 14.33; 12.5 & 16.5; 7 & 9.25; 7.5 & 16.75; 16.25 & 18.75; 12.5 & 16; 8 & 16.25; 5.75 & 14.33, and 5.83 & 18.33 respectively.The results of pollen compatibility showed that the abilities of Gerdooii and Gerge of varieties as pollen donor and receptor were different. It was found that variety Gerdooii is an excellent pollinizer for varities: Fertile, Rasmi, Shastak-2, Negret and Gerdooii respectively. But variety Gerge is an excellent pollinizer for varieties: Gerdooii, Fertile, Rasmi, Negret, Shastak-2 and Gerge.Finally, among studied varieties in this exprimen, it was found that Fertile du cutard has the highest fruit set (13.95%) while the least fruit set was recorded for Gerge (10.29%).
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