Determination of Damage Index of Olive Fruit (Koroneiky variety) in Different Harvesting Methods and Times in Golestan Province

Abstract

Introduction Olive is one of the plants, that has been cultivated for long in Iran. The average extracted oil is about 65 kg per tree. Four to five kg olives give approximately one liter oil. Olive harvesting problem, is one of the obstacles to development cultivation in Golestan province. Concurrency olive harvesting time with a number of field crops, seasonal precipitation and a lack of the workers are some limitations for development of this fields. Investigative study of the alternative methods instead of the traditional can be desirable strategy for cultivation development of this product. But gardeners are not eager to use this equipment due to lack of harvesting machine. With regard to the afore-mentioned items, the objective of this study was to determine the appropriate method, the optimal time and interaction effect of the two afore-mentioned factors on the measured traits in order to damage reduction during harvesting time. Materials and Methods This research was conducted with the two factors, i) date of harvesting and ii) harvesting method. In this regard, harvesting operation carried out at the three dates including; i) 19 December, ii) 3 January and iii) 18 January in 2015. At the three afore-mentioned harvesting dates; olives were harvested with the three methods including; i) traditional (hitting with the long wood by worker), ii) manual comb and iii) motorize pneumatic comb shaker. The measured traits during operations before and during the harvesting time were the abscission naturally percentage, at the start and the end of the harvest, amount of harvesting (harvested fruit percentage), the remaining fruits percentage on the tree, damaged fruits percentage and damaged fruit index. The experimental design carried out in this research was a split plot based on the randomized complete block design, with three replications. The main plots attributed to olive harvesting time at three levels. The sub-plots attributed to types of olive harvesting method at three levels. After sampling and data collection, the data were set in the Excel software. The obtained data analyzed by using SAS software. Analysis of variance (ANOVA) and comparison of means extracted from the output of analysis of the data with a probability level of 5%. Results and Discussion Interaction effect of harvesting time and harvesting method on maturity index was significant at 1% level (Table 1). The lowest and highest value of maturity index occurred at the time of 19 December and 18 January (2.28 and 4.07), respectively. The effect of harvesting time on naturally abscission percent was significant at the 5% level. The lowest (1.16) and highest (2.21) naturally abscission attributed at the time of 18 December and 18 January, respectively. The effect of harvesting method on the percentage of the remaining fruits on the tree was significant at the 1% level. The lowest (2.71%) and the highest (5.89 %) value of the remaining fruits occurred in the manually comb and traditional methods, respectively. The effect of harvesting method on the amount of remaining fruit on the tree per kg of harvesting was significant at the 1% level. The highest (62.86 gr) and the lowest (27.92 gr) value of this trait yielded in the traditional and manually methods, respectively. Interaction effect of the harvesting time × harvesting method on the damaged fruits was significant at 1% level. The highest and the lowest values of the damaged fruits took place in 19 December and in the traditional and the manual comb methods, respectively. The effect of harvesting time on abscission leaf percent was significant at the 1% level. The highest value of 13.2% and the lowest value of 4.47% occurred in 18 January and 19 December, respectively. Interaction effect of harvesting time and harvesting method on the damaged fruits index, was significant at the 1% level in 18 January. The highest (1.002) and the lowest (0.424) yielded in traditional and manually comb methods, respectively. Conclusions The results showed that in order to percentage of remaining fruits on the tree, remaining amount on the tree per kg, damaged fruit and damaging fruit index, the best method of olive harvesting is the manually comb method. The lowest percentage of leaves abscission naturally occurred on 19 December. The Lowest percentage of leaf abscission was on 18 January. So the best of olive harvesting method (variety Koroneiky) in the study area, the use of manual comb with maturity index 3.58 is suggested.

Keywords

• damage index
• harvest methods
• harvest time
• maturity index
• olive