Effects of some periodisity control applications on olive and olive oil yield and quality in memecik olive variety

Memecik olive variety, which is an importantoil-producing type in our country and especially the Aegean region, exhibits a strong alternate bearing tendency. In order to reduce the tendency for alternate bearing, cultural practices (irrigation, fertilization, pruning, thinning, use of plant growth regulators, etc.) that will cause a balanced flower bud stimulation in alternate bearing control must be carried out. For this reason, this study was planned to reveal the effects of some applications for the control of alternate bearing on olive yield and quality and olive oil quality in Memecik olive variety. The study, which was initiated by selecting productive and unproductive trees in the 2020 vegetation period in the Memecik olive garden located in the Central Campus area of Aydın Adnan Menderes University, was carried out for three years. In order to reduce the severity of alternate bearing; besides a control group, different practices; i.e. (early harvest and late harvest) hand thinning, chemical thinning (180 ppm NAA-K), gibberellic acid (75 and 150 ppm GA3), anti-gibberellin (125 and 250 ppm pro-Ca) applications were implemented. In order to control the alternate bearing, the effect mechanisms for each practice/application were taken into consideration. GA3 applications were made on "off" trees while the other applications were made on "on" trees, in the same orchard. In order to determine the effects of the applications, in addition to phenological observations on olive trees, yield per tree, maturity index, fruit sizes, number of grains per kg, flesh/seed ratio, titratable acidity, pH and total water-soluble dry matter values were determined. In terms of olive oil quality, analyses were made regarding free fatty acids, peroxide and iodine number, amount of saturated and unsaturated fatty acids, sterol components, total tocopherol, UV specific absorbance, total phenolic substance and fatty acid composition. When the results obtained from the trials are evaluated in general; positive effects of GA3 and fruit thinning applications have been determined in terms of both yield per tree and olive and olive oil quality.