Sahar Sedaghat; Majid Rahemi; Elham Aslmoshtaghi
Abstract
Hot air treatment has been applied on a wide range of horticultural crops to control postharvest decay and to maintain quality characteristics. To evaluate the effect of hot air treatment on physio-chemical properties of pomegranate arils, an experiment was carried out in a factorial experiment using ...
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Hot air treatment has been applied on a wide range of horticultural crops to control postharvest decay and to maintain quality characteristics. To evaluate the effect of hot air treatment on physio-chemical properties of pomegranate arils, an experiment was carried out in a factorial experiment using a completely randomized design with four replications in 2015. About 200 g of ‘‘Rabab-e-Neyriz’’ pomegranate arils were placed in 350 mg polypropylene boxes with three holes on top for ventilation. Boxes were heated at 35 °C, 40 °C and 45 °C and 80% relative humidity for 30, 60, and 120 min in oven. After being cooled at an ambient temperature, boxes were stored at 5 °C (RH= 70-80%) for 15 days. The scored results of decay assay showed that heated “Rabab” arils at 35 °C till 45 °C decayed lesser than those untreated during storage period. Hot air temperature at 45 °C for 120 min resulted in the highest weight loss at the end of storage period. The highest total soluble solids content was belonged to the arils heated at 45 °C for 30 min. Hot air treatments increased pH and TSS/TA ratio of aril juice. Hot air temperature treatment decreased antioxidant activity, total phenolic compounds and total anthocyanin of arils during storage period, whilst hot air treatment had no significant effect on color values. Generally, the application of mild heat treatments could be considered as a non-contaminant postharvest tool to maintain functional and nutritive properties of arils during postharvest storage.
Amin Hassankhah; Kourosh Vahdati; Majid Rahemi; Darab Hassani; Saadat Sarikhani Khorami
Abstract
Walnut production is limited by late-spring frost in many countries. The current research was carried out to evaluate chilling and heat requirement of catkin and terminal buds break on six selected superior walnut genotypes and cultivars (‘C-25’, ‘88-1’, ‘88-2’, ‘Chandler’, ...
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Walnut production is limited by late-spring frost in many countries. The current research was carried out to evaluate chilling and heat requirement of catkin and terminal buds break on six selected superior walnut genotypes and cultivars (‘C-25’, ‘88-1’, ‘88-2’, ‘Chandler’, ‘Jamal’ and ‘Damavand’). The Utah and accumulation growing degree hours (GDH) models were applied to determine the chilling and heat requirements under field and greenhouse conditions, respectively. ‘Damavand’ cultivar (650 CU) and ‘C-25’ genotype (650-800 CU) had the lowest chilling requirement for terminal bud break. ‘Jamal’ cultivar and ‘C-25’ genotypes had the lowest chilling requirement to break the dormancy of catkins (650–800 CU). ‘Chandler’ cultivar and ‘88-1’ and ‘88-2’ genotypes as late-leafing genotypes/cultivars had the highest chilling and heat requirements to break dormancy of terminal buds (800-1100 CU and 11832-12648 GDH) and catkin (800-950 CU and 11484-12180 GDH). In conclusion, late-leafing genotypes/cultivars had the higher heat requirement than early-leafing genotypes/cultivars. Based on the results, a linear and significant relation was observed between chilling requirement and heat accumulation. Therefore, heat accumulation of buds and catkins was reduced by increase in the amount of chilling requirement. Furthermore, the result revealed that heat accumulation is more important than chilling requirements to estimate walnut budbreak date. The GDH of catkins and terminal buds was decreased with increase in the average temperature during heat accumulation.
Majid Rahemi; Fateme Yazdani; Sahar Sedaghat
Abstract
Selection of frost tolerant cultivars and understanding the mechanisms of frost hardiness could help to improve freezing resistance in olive plants. Olive cultivars may differ in frost hardiness due to differential survival of specific organs. The aim of this study was to screen different olive cultivars ...
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Selection of frost tolerant cultivars and understanding the mechanisms of frost hardiness could help to improve freezing resistance in olive plants. Olive cultivars may differ in frost hardiness due to differential survival of specific organs. The aim of this study was to screen different olive cultivars based on their stomatal density and metabolic modifications under cold conditions. The ‘Zard’ cultivar had the lowest while ‘Derak’ had the highest stomatal density, respectively. In another experiment, where entire potted olive plants were subjected to freezing stress (0, -6, -12 and -18 ˚C), ‘Zard’ and ‘Dehghan’ were found to be the most tolerant cultivars. They showed the lowest starch content, ionic leakage and wood injury. They also had the highest reducing sugar, phenolic and proline contents among studied cultivars. We concluded that ‘Zard’ and ‘Dehghan’ are the most tolerant cultivars and ‘Derak’, ‘Dakal’ and ‘Shiraz’ are the most sensitive cultivars to freezing injury.
Kobra Tavakoli; Majid Rahemi
Abstract
This study was conducted to evaluate the effects of exogenous polyamines, isopropyl ester, 2, 4-D and naphthalene acetamide application on yield and quality of date palm of ‘Kabkab’ cultivar. The inflorescences sprayed with 2, 4-D isopropylester (0, 10, and 20 mg L-1), naphthalene acetamide ...
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This study was conducted to evaluate the effects of exogenous polyamines, isopropyl ester, 2, 4-D and naphthalene acetamide application on yield and quality of date palm of ‘Kabkab’ cultivar. The inflorescences sprayed with 2, 4-D isopropylester (0, 10, and 20 mg L-1), naphthalene acetamide (0, 80, and 120 mg L-1), putrescence and spermidine (0, 0.1, and 1.0 mM), three or six weeks after pollination. The highest rate of initial fruit drop (42.2%) was obtained when fruits were treated with naphthalene acetamide at a concentration of 120 mg L-1, which was significantly higher than the control (32.0%). Fruit treated with polyamines had a higher yield than the control. The lowest total soluble solids (TSS) (21.5%) were found in spermidine 0.1 mM and the highest TSS (46%) was found in the control. Polyamines decreased fruit total soluble solids content (TSS) compared with untreated fruits, and also delayed fruit maturity for at least 17 days. In conclusion, polyamine application significantly affected yield, physical and chemical characteristics of date cultivar under the study and it may be recommended to be applied in cultural practices to enhance production and improve the fruit quality of date trees orchards.
