Pomology
Alireza Bonyanpour
Abstract
IntroductionPomegranate is a native fruit tree to Iran and has the best growth and performance in subtropical climate conditions. In recent years, due to environmental stresses conditions such as high temperature, high light intensity and low irrigation water a large number of orchards have faced to ...
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IntroductionPomegranate is a native fruit tree to Iran and has the best growth and performance in subtropical climate conditions. In recent years, due to environmental stresses conditions such as high temperature, high light intensity and low irrigation water a large number of orchards have faced to physiological problems such as fruit cracking, sunburn and a decrease in fruit quality. The high temperature along with high evaporation and transpiration can be considered as the main cause of these abnormalities, which causes disturbances in the process of plant metabolism and finally causes physiological disorders. Sunburn of the fruit is caused by high temperature and high sunlight intensity and has a negative effect on all the quality characteristics of the pomegranate fruit. Using net shade is one of the recommended ways to reduce the impact of climate change. Application of net shading in areas with high radiation levels has led to a decrease in the intensity of light radiation received by the canopy of the trees, which causes a decrease in the temperature of the leaf surface, and decrease the level of evaporation and transpiration in the trees. Materials and MethodsThis research was conducted during 2019-2020 for 2 years in a private orchard in the Kohmar area of Kazeron city of Iran. ́Rabab̕ pomegranate trees that were planted at a distance of 5 x 5 m and 15 years old were used. In this research, the effect of different types of net shading was investigated. The experiment was conducted as a randomized complete block design with 9 treatments and three replications in two years. The experimental treatments included the use of net shading in white and green colors with two different shading (30% and 50%) and two implementation methods (on the base and on the canopy of the tree) which were compared with control trees (without cover). During the growing season, measurements were made in relation to leaf temperature, sunlight intensity, soil moisture, relative water content of leaves, fresh and dry matter of leaves, and prolin content, and at the time of harvest, the percentage of sunburn, cracking and aril paleness of the fruit, thickness of fruit peel and anthocyanin content of fruit juice in all treatments were measured. Results and DiscusionsThe use of net shading increased the quantitative and qualitative characteristics of pomegranate fruits. The results of this research showed that the use of white and green nets 50% and green net 30% on the base had the best results. By using the appropriate type of net shading, the temperature of the pomegranate tree was reduced by about 6 degrees Celsius. Net shading also reduced the light intensity by at least 50%; the reduction of light intensity in green nets was more than in white nets.The highest relative water content was 85% in the green net shade (50% with base) treatment. Net shading significantly increased the water content of the leaves compared to the control.The use of net shading significantly reduced the percentage of sunburn on fruits compared to the control. Sunburn was about 14% in the control treatment and less than 5% in the net shading treatments. Net shading reduced the percentage of fruit cracking from 15 percent in the control treatment to about 7 percent in all shading treatments. ConclusionThe use of net shading as a cover for pomegranate trees reduces the temperature of the canopy of the plant by reducing the radiation of the sun, and by better maintaining the moisture of the soil of the pomegranate tree. It reduces the heat and drought stress condition and has a positive effect on the quantity and quality of the fruit produced. Among the treatments used, the use 3 types of net including 50% white nets on the base, and 30% and 50% green nets on the base had the best results. These treatments better than others in terms of shading percentage, temperature reduction, and improving the quantity and quality of pomegranate fruits . Net shading should be installed when the fruits are about 5 to 7 cm in diameter and will remain on the tree until mid-September. This type of tree shading did not leave any side effects on the quantity and quality of the fruits.
Pomology
Alireza Bonyanpour; Babak Jamali
Abstract
Introduction
Pomegranate (Punica granatum L.) is a nutrient dense fruit with a high health value and one of the most important Iranian fruit crop. Historical evidence reveals that the primary origin of pomegranate is Iran and that it has been spread from this region to other areas. A vast range of pomegranate ...
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Introduction
Pomegranate (Punica granatum L.) is a nutrient dense fruit with a high health value and one of the most important Iranian fruit crop. Historical evidence reveals that the primary origin of pomegranate is Iran and that it has been spread from this region to other areas. A vast range of pomegranate varieties can be found in Iran; 760 original, decorative and wild ones. Pomegranate juice contains a high amount of total soluble solid (TSS), anthocyanins, polyphenolic compounds, vitamin C, sugars and proteins.Pomegranate is considered as one of the most tolerant fruit crops capable of growing under arid and semi-arid climatic conditions. Cultivar and growing region climate are the main factors determining chemical composition of pomegranate fruits; Significant differences in various fruit quality parameters such as organic acids, phenolic compounds, sugars and water-soluble vitamins have been reported in previous studies. The aim of present study was to compare and evaluate physical and biochemical characteristics of fruits and different polyphenolic compounds in juice of six commercial Iranian pomegranate cultivars.
Materials and Methods
This research was conducted in 2017 and 2018 years in a commercial orchard in Arsanjan region of Fras province. Six Iranian pomegranate cultivars included ‘Malas Yusef Khani’ (MYK), ‘Bajestani (BK), ‘Khazr Bardskan’ (KHZ), ‘Malas Dane Syah’ (MDS), ‘Rabbab’ (RB) and ‘Zard Anar Arsenjan’ (ZA) were studied. The trees were planted in randomized block design and spaced 5 and 3 m between and along the rows, respectively. The trees were grown under drip irrigation with routine cultural practices suitable for commercial fruit production. Orchard management was conducted uniformly according to optimized available recommendations (based on soil and water samples analysis) for the orchard site. Fruits were harvested randomly from orchard and some physicochemical characteristic of fruits were measured. Fruit length and fruit diameter measured by manual caliper, fruit and above ground weight was determined by digital scale. The fruit juice percentage was calculated by calculating the percentage of aril juice. TSS (Total soluble solids) expressed in Brix◦ was measured using a refractometer. The titrable acidity (TA) was determined by titration to pH 8.1 with 0.1M NaOH solution and expressed as percentage.Total anthocyanins, total polyphenols, vitamin C and anthyoxidant activity were measured spectrophotometrically. Polyphenolic compositions of juices (Gallic acid, Catechin, Caffeic acid, Chloregenic acid, p-Coumaric acid Vanilin, Trans-ferulic acid, Hesperedin and Ellagic acid) were also measured using HPLC analysis. The chromatographic analysis was carried out on Agilent Technologies 1200 series HPLC system. Chromatograms were recorded at 280 and 320 nm. Each compound was quantified by comparing its peak. Data was analyzed by SPSS software and means were compared using Duncan’s multiple range tests at 5% probability level.
Results and Discussion
Significant differences were found among studied pomegranate cultivars for various physical fruit characteristics, quality parameters and polyphenolic composition of fruit. ‘Malas Daneh Syah Yazd ’was the best in comparison to other cultivars. ‘Malas Daneh Syah Yazd’ had the highest fruit weight (332 g), fruit length (8 cm), fruit diameter (8 cm), TSS(15.77 Brix◦), anthocyanin content (26.98 mg 100 ml-1), polyphenol content (514.37 mg 100 ml-1) , ascorbic acid content (9.23 mg 100 ml-1) and antioxidant activity (52.2%). Also, the amount of polyphenols in this cultivar was relatively high. This cultivar had high amount of some polyphenol content such as cathechin (223.5 mg L-1), Hesperidin (30.55 mg L-1) and Ellagic acid (43.02 mg L-1) with no significant differences with highest amount. ‘Rabbab’ had the highest aril weight (340 mg) and moderate levels of other fruit characterestics, this cultivar had the maximum polyphenols such as gallic acid (163.1 mgL-1), catechin (264.2 mgL-1), caffeic acid (265.1 mgL-1), p-Coumaric (74.41 mgL-1) acid, vanillin (18.21 mgL-1) and ellagic acid (43.5 mgL-1). Zard anar’ pomegranate cultivar which was native to this region in terms of most biochemical properties had a low a‘mount .Therefor, among the studied pomegranate cultivars‘ Malas Dane syah’ and was the best. This cultivar had the highest fruit characteristics and polyphenol content such as ellagic acid.
Conclusion
The results of this study showed significant differences among studied pomegranate cultivars. ‘Dane syah Yazd’ had the highest physical and chemical characterestics of fruits. Previous studies showed that theses cultivars had good growth characteristics and high yield in comparison to other cultivars. Therefore, among the studied cultivars, ‘Dane syah Yazd’ is introduced as a suitable cultivar for this region. Also, ‘Rabbab’ Neyriz cultivar can be considered as a cultivar with high antioxidant properties of fruit juice due to having the highest amount of measured polyphenolic compounds, especially alginic acid.
