Quality Improvement and Fruit Ripening Acceleration in Date Palm cv. Kabkab Using Colored Covers and Bunch Positioning

As one of the oldest fruit trees, palm, from almost 5,000 years ago till now, has been growing in North Africa and the Middle East. Phenological ripening process of fruit trees are determined through factors such as genetic, environmental and controlled practices. Among these factors, radiation as a natural factor affects other processes such as photosynthesis, flowering, performance and color of a fruit. Considering the importance of producing organic fruits, it is highly effective to use different coatings to improve the gardening products .Results of this study showed the effect of light on strawberry fruit coating which has the capacity to pass higher levels of UV light. As a result of applying coating the average fruit weight, fruit number, phenols, pigments, anthocyanins and flavonoids were significantly increased, but no significant difference was observed for the total yield. Use of coverage on apple trees reduced physical damage and improved the color of the fruit. The blue covering improved the physical and chemical factors in banana. Date palm bunch covers offer several advantages to protect fruits from high humidity and rain, from bird attacks and also from damage caused by insects and diseases. A sturdy light-brown craft-paper is used in the USA to cover and provide good protection of the bunch during the ripening season. Bunch covering is, however, not only practiced against rain damage but traditionally is also used in the form of coarsely woven well-ventilated baskets (sund) to protect the maturing fruits from birds and prevent early ripening fruit from falling to the ground. Bagging treatment has been widely used as a physical protection technique in other fruit-tree species for not only protecting fruits from diseases and pests, but also changing the microenvironment of fruit development growth, which subsequently affects internal and external qualities, such as skin color, acidity, sweetness and aroma. A large number of experimental data obtained in peach, pear, apple etc, showed that bagging treatment might lead fruits to increase or decrease of ascorbic acid (Vc), TSS, anthocyanin, organic acids contents etc. This study also aimed to show how the quality, quantity and speed of the ripening process of fruit date palm Kabkab can be improved using covering method. This research was carried out at the Tropical Fruits and Dates Research Station in Bushehr Province. Considering the above purpose, a complete randomized block design was employed. Accordingly, 6 treatments including bags with dimensions of 120 × 70 cm in 5 colors (green, yellow, white, gray, and blue) and with a four-time repeating pattern were applied to 20 years old Kabkab palm trees. All trees were pollinated by a controlled pollinator. Factors measured included the ripening speed of fruit per unit of time, the weight of the entire cluster, cluster weight, fruit weight, TSS, TA and pH. Data collection and Analysis: factorial complete randomized block design was carried out and data were analyzed statistically by analysis of variance and least significant differences (LSD 5%). Based on the results obtained, the direction and color of the bag on the characteristics of fruit appearance has no significant effect. Awad (2007) achieved similar results with colored bags including black, white, blue and white coating on the date palm Helali obtained. Alcobendas (2012) found that the geographical location of peach fruit on the tree has no effect on the weight of meat, fruit weight, fruit diameter, fruit dry weight and pulp to stone ratio. The results showed that bunch weight and fruit weight significantly increased in the north. Tyas et al (1998) reported lychee trees in directions of northeastern and northwestern produces the highest and directions of southwest and the southeast had the least amount of fruit. Gray coverage significantly increased the rate of ripening of the fruit in the unit time in both years. Awad (2007) said it might be possible that bunch bagging, especially with black and blue polyethylene bags, accumulated higher heat units than other bags and the controls. Consequently, accumulated heat might induce higher respiration rates and the CO2 accumulation within bags might lead to more acetaldehyde production and removal of astringency. According to data obtained from physiological factors it can be concluded that palm bunch covering accelerates the ripening of fruits. Also, the data obtained from the directions of bunch shows those bunches located on the north side of the palm tree weigh more.