VEGETATIVE GROWTH AND INFLORESCENCE BUD ABSCISSION IN BEARING AND NON BEARING PISTACHIO TREES

A study on shoot growth, leaf area development and inflorescence bud abscission in bearing and non-bearing deblossomed trees, has been carried out in a commercial pistachio orchard located at Agrigento (Sicily, 37°30'N). Growth pattern of shoots, leaves and inflorescence buds was monitored in an "on " year on twenty Bianca/P. terebinthus trees. Twenty days before full bloom half of the selected trees were deblossomed by excising inflorescences from the entire tree whereas the remaining trees were used as control. Starting from the date of deblossoming until the onset of bud drop, two-year branchlets per tree were periodically collected and divided into two and one-year old wood, fruits, leaves, inflorescence buds and current year stem. On such material data concerning growth and dry matter accumulation were collected. The results are discussed and referred to the alternate bearing phenomenon.