LEAF PHOTOSYNTHESIS OF SIX IRANIAN PISTACHIO (PISTACIA VERA L.) CULTIVARS AT SIX FRUIT DEVELOPMENT STAGES

Photosynthesis rate (PI) in the leaves from braches with and without fruits in six Iranian commercial pistachio cultivars (‘Ouhadi’, ‘Ahmad-Aghaie’, ‘Akbari’, ‘Kalleh-Ghochi’, Haratii’, and ‘Rezaie-Zoudras’) was studied during five fruit development stages (beginning of endocarp growth, pit hardening, beginning of endosperm rapid growth, end of embryo development, and ripening) and post harvest. There was a significant difference in PI among cultivars. ‘Rezaie-Zoudras’ and ‘Haratii’ had the highest and the lowest PI respectively. Cultivars showed significant differences in PI at different fruit development stages. The highest PI was observed in the first stage followed by the second, third and sixth stages. It seems that both temperature and fruit development stage affected PI. There was no significant difference in PI between with fruit and without fruit branches.