جستجوی مقالات مرتبط با کلیدواژه « Vitamin C » در نشریات گروه « زراعت »

To evaluate the effect of seed priming with ascorbic acid to increase salt tolerance in Chenopodium quinoa var. Giza 1 during the vegetative growth period, the current research was conducted in the form of a factorial experiment (ascorbic acid at three levels of 0, 20 and 60 mM and NaCl at two levels of 0 and 400 mM) and based on a completely randomized design. The traits measured in the experiment were fresh and dry weight, concentration of photosynthetic pigments, hydrogen peroxide (H2O2) and malondialdehyde, and the activity of antioxidant enzymes. Data analysis showed salinity resulted in a significant decrease in the amount of dry weight (51.4%), fresh weight (65.6%) and total chlorophyll (55.8%). In addition, salinity increased the content of malondialdehyde (2.3 folds), hydrogen peroxide (2.5 folds) and the activity of antioxidant enzymes (catalase, ascorbate peroxidase and guaiacol peroxidase). However, seed priming with ascorbic acid at the best level (20 mM) alleviated the adverse effects of NaCl in this variety by increasing the fresh weight (44.7%), dry weight (51.4%), and protecting membrane integrity and photosynthesis activity. Also, the use of ascorbic acid by changing the activity of antioxidant enzymes and reducing the content of hydrogen peroxide caused a reduction in oxidative stress in in this variety. It can be concluded that seed priming of this variety with 20 mM ascorbic acid can be effective on its successful cultivation in high salinity levels.

Long-term use of chemical fertilizers can cause many adverse effects. In addition, excessive consumption of chemical fertilizers can lead to decreased food safety and low quality of vegetables, such as the accumulation of nitrates in plants. Today, using organic fertilizers is an efficient way to achieve sustainable agricultural development. The release rate of nutrients from organic fertilizers is slow and hardly exceeds the absorption capacity of plants compared to chemical fertilizers.

To compare the effect of chemical and organic fertilizers on the quantitative and qualitative traits of tomatoes in field conditions, an experiment was conducted in the cropping year of 2020-2021 in a randomized complete blocks design with three replications in the research farm of the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. Experimental treatments included: 1- biochar (8 t.ha-1), 2- animal manure (30 t.ha-1), 3- vermicompost (25 t.ha-1), 4- NPK chemical fertilizer (225 kg.ha-1 urea, 150 kg.ha-1 phosphorus fertilizer and 150 kg.ha-1 potassium sulfate), 5- 50% biochar + 50% animal manure, 6- 50% biochar + vermicompost, 7-50% animal manure + 50% vermicompost, 8- 50% biochar + 50% NPK, 9- 50% animal manure + 50% NPK, 10- 50% animal manure + 50% NPK, 11- 25% biochar + 25% animal manure + 25% vermicompost + 25% NPK and 12- control. The harvesting operation was carried out in two cutting. Five plants were randomly selected in each plot, and traits such as fruit size, length, and diameter were measured. Also, total yield, Brix index, vitamin C, and lycopene were measured in both cuttings.

In the first and second cutting, the highest fruit volume was obtained in the treatment of NPK chemical fertilizer (80.5 cm-3) and the combined use of NPK chemical + animal manure (131 cm-3), respectively. In the first cutting, the maximum fruit length was reported in the treatment of NPK chemical fertilizer (5.61 cm), and the second cutting, in the combined application of NPK chemical fertilizer + animal manure (7.16 cm) that compared to the control (4.73 cm) had a longer fruit length of 51%. The largest fruit diameter was observed in the NPK chemical fertilizer treatment (5.01 cm), which was 16% more than the control (4.31 cm). On the other hand, in the second cutting, the largest fruit diameter was shown in the combined application of chemical NPK + manure (5.54 cm). In the first cutting and the total of both cuttings, the highest yield was observed in the treatment of NPK chemical fertilizer (39.6 and 70.5 t.ha-1, respectively), while in the second cutting, the highest yield was obtained in the combined treatment of NPK chemical fertilizer + animal manure. (32.8 ton.ha-1). The results showed that using organic fertilizers individually and combinatorial compared to NPK chemical fertilizers had more Brix index, vitamin C, and lycopene. The highest amount of Brix index in first and second cutting (6.55 and 7.13, respectively), vitamin C (12.9 and 11.4 mg.100 g sample-1, respectively), and lycopene (2.48 and 2.25 mg.100 g sample-1, respectively) in the combined treatment of animal manure + vermicompost. Since the elements in the chemical fertilizer are released faster than the elements of other fertilizers and are available to the plant, therefore, by increasing the initial growth of the plant and as a result of improving its flowering potential, the total yield increased, in particular in the first cutting, where the superior treatment was the NPK chemical fertilizer. Further, due to the gradual release of organic fertilizer elements, the combined treatment of chemical and organic fertilizers increased the yield. On the other hand, organic matter plays an important role in soil fertility and performance. The rare elements in organic matter can meet the needs of soil microorganisms, enhance microbial activities, affect soil-microorganism interactions, and indirectly affect crop quality.

The use of organic fertilizer, when combined with chemical fertilizer, can enhance both the qualitative and quantitative characteristics of tomatoes. By substituting a portion of chemical fertilizer with organic fertilizer, not only can yield be improved, but it's also possible to reduce the consumption of costly chemical fertilizers. This approach aligns with sustainable agricultural goals by optimizing the use of organic fertilizers.

Sweet pepper is a rich source of essential vitamins and minerals. On the other hand, pepper fruit contains high levels of antioxidants and beneficial substances such as vitamin C, carotenoids and phenolic compounds. It also contains high concentrations of potassium. These compounds has nutritional and antioxidant capacity. Sweet pepper originated from the tropical region, which is sensitive to cold. Therefore, it is necessary to know the defense mechanism of the pepper plant against low temperatures. In this study, the effect of foliar application of salicylic acid and vermicompost on different cultivars of sweet pepper under cold stress has been studied.

The experimental design was a factorial split-plot experiment in a randomized complete block design with three replications in a greenhouse located in Mashhad in the crop year 1396 and 1397. Cultivation was performed hydroponically. The main factor of temperature treatment had two levels [9 ± 2°C (cold stress) and 23 ± 2°C (optimum)] and the sub factor consisting of two sweet pepper cultivars (green, yellow) and Different amounts of Salicylic acid (The dose of 0 μmol salicylic acid was used as control group, 200, 300 μmol) and vermicompost). Sampling of the plants at the end of the growing season, to measure the physiological characteristics and quality were randomly.

The results showed that there was no significant difference between different cultivars in most traits except vitamin C, beta-carotenoids and lycopene. Maximum dry matter (17.2g), TA (13.6 g l-1) in non-stress cold treatment, and soluble solids (5.03 brix),, carbohydrates(174.5 mg g-1), and anti-activity Oxidation (90.3%)  were obtained in cold stress treatment. Damage due to cold stress destroyed the structure of many membrane lipids and resulted in an increase in the amount of antioxidant compounds. Soluble solids are known to be key components in increasing cold resistance. An increase in the amount of soluble solids in winter is part of the plant's adaptation mechanism to cold. The highest yield of fruit per plant(740 g) was obtained in non-cold stress treatment plus salicylic acid 300 μmol. Because salicylic acid in plants improves yield and yield components. Maximum of flavonoids (159.4 mg g-1) was obtained in salicylic acid 200 μmol. Flavonoids are a large group of phenolic compounds in plants that increase their production in environmental stresses by increasing the activity of PAL enzyme. On the other hand, the use of salicylic acid as a stressor causes the production of a wide range of flavonoids. The highest amount of beta-carotene and lycopene were obtained in cold stress treatment, yellow cultivar, and salicylic 300 μmol. Decreased content of carotenoids under stress can be due to oxidation by active oxygen and damage to their structure. Increased photosynthetic pigments under SA treatment indicate the protective effect of this growth regulator on photosynthesis and photosynthetic pigments of stressed plants. Maximum vitamin C was obtained in cold stress treatment (140.7 mg 100 g-1, yellow cultivar (134.7 mg.100g-1), and salicylic 300 μmol (142.52 mg.100 g-1).

According to the results, the of the present study show that use of salicylic acid foliar application modulates the effect of cold stress on the physiological and functional parameters of sweet pepper so that SA can improve cold tolerance by regulating the activities of apoplastic antioxidative enzymes. Therefore, it is suggested that due to sudden changes in temperature due to climate change and the destructive effects of temperature stress, especially cold, on plants, more and more complete research should be done to identify the effects of these stresses and ways to deal with them.

The objective of this study is to evaluate the effect of different methods of complementary pollination on the qualitative characteristics of kiwifruit cv. Hayward in order to introduce the most effective and practical complementary pollination method.

The present study evaluated the effect of different methods of complementary pollination [open pollination, hand pollination from male flowers of the tumor cultivar, spray pollination with pure pollen and spray pollination with impure pollen (collected from the entrance of bees' nests at the time of opening kiwifruit male flowers) on the qualitative characteristics of kiwifruit cv. Hayward in the Citrus and Subtropical Fruits Research Institute (Ramsar city) in 2021 based on the randomized complete block design in three replications.

The results showed that the amount of titratable acids, maturity index, chlorophyll b, carotenoid, total flavonoid and antioxidant activity were not affected by different methods of complementary pollination. Fruits obtained from spray pollination with impure pollen had the highest single tree yield (98.32 kg per tree), hectare yield (40.39 tons per hectare), number of seeds (1038), amount of soluble solids (7.07 °Brix), chlorophyll a (1.71 mg100 g-1 FW), total chlorophyll (3.11 mg100 g-1 FW), vitamin C (60.27 mg100 g-1 FW), and total fruit phenol (79.62 mg100 g-1 FW). Moreover, these fruits were in more favorable conditions regarding sensory and taste evaluations.

Overall, it is possible to recommend complementary pollination according to spray pollination with impure pollen as the most effective and practical method to increase fruit quality for kiwifruit growers.

The shelf life of orange ‘Thomson Navel’ (Citrus sinensis var. Thomson Navel) is low. One of the important factors in maximum increase of fruit quality and its nutritional value is the presence of calcium and potassium in fruit tissue. Absorption of essential elements from the soil by the roots and their transfer to the aerial part of the plant, including entry into the fruit tissue are important challenges. Calcium deficiency in citrus fruits is possible due to reduced absorption from soils. The application of these elements in the form of foliar application solves this challenge. The aim of this study was to determine the appropriate frequency of combined treatment of calcium and potassium (one to four times), before and after harvest, on shelf life and fruit quality of Thomson Novell cultivar, including calcium, vitamin C and soluble solids (°Brix).

Treatments were without foliar application of calcium, once foliar application of calcium (in June), twice foliar application of calcium (in June and July), three times foliar application of calcium (in June, July and September), four times foliar application of calcium (in June, July, September and October), without foliar application of potassium, once foliar application of potassium (in June) and twice foliar application of potassium (in June and July), alone or in combination with a week distance and before harvesting fruits. After harvesting, all fruits were treated with 3 per 1000 calcium for 5 minutes as plunging. Fruits without foliar application of calcium and potassium were considered as controls. Calcium foliar application was performed at a constant rate of 3 per1000 and potassium foliar application at a rate of 2 per 1000. The last stage of treatment of fruits with calcium was done after harvest and by immersion in a solution of 3 per 1000. The experiment was conducted in a completely randomized block design with three replications in Kharik village of Sari city. The fruits were stored at the temperature of 5°C and 85% relative humidity for 3 months. Traits of length, diameter, skin diameter, weight, juice volume, decay, vitamin C, calcium, total solid soluble (TSS), titration acidity (TA) and acidity (pH) of fruits were measured after 3 months’ storage.

The results showed that the most vitamin C (97.69 mg/100 ml fruit juice), fruit weight (242.20 g) and fruit juice volume (115.70 ml) were obtained in fruits treated with twice foliar application of calcium (in June and July at a rate of 3 per1000) together with twice foliar application of potassium (in June and July at a rate of 2 per1000). The highest diameter (78.92 mm) and the lowest decomposition were obtained in fruits treated with twice calcium (June and July at a rate of 3 per1000) together with once potassium (June at a rate of 2 per1000). The highest amount of fruit calcium (165.30 g/kg DW) was calculated in the treatment of 3 times foliar application of calcium (in June, July and September at a rate of 3 per1000) together with once foliar application of potassium (in June at a rate of 2 per1000).

In general, based on the findings of this study, foliar application of Thomson Novell cultivar through twice calcium (in June and July, at a rate of 3 per 1000) and once with potassium (in June at a rate of 2 per1000) and twice with potassium (in June and July, at a rate of 2 per1000) before harvest along with plunging into 3 per 1000 of calcium after harvest (for all oranges) is suitable for maintaining the quantity and quality of fruits during storage and this treatment is recommended.

Microgreens are young plants that have gained popularity among consumers due to their high nutritional value. In the present study, the shelf life and nutritional properties of beet microgreens subjected to silicon and nano-silica in the post-harvest period have been investigated. Silicon and nano-silica treatments were carried out at two levels (Control and 100 mg/L as foliar spraying), after which the microgreens were harvested and kept at 4°C for 12 days. The results showed that the activity of polyphenol oxidase enzyme increased with the increase of storage time and as a result the browning of the tissue also increased. Also, with increasing storage time, the percentage of weight loss, hydrogen peroxide, malondialdehyde and carotenoid increased and chlorophyll a, b and total, total phenol, flavonoid, antioxidant capacity and vitamin C decreased. The use of silicon and nano-silica treatment decreased the activity of polyphenol oxidase enzyme and browning of the microgreen tissue compared to the control. Application of silicon increased total chlorophyll (33.75%), total phenol (2.49%) and total antioxidant capacity (39.7%) of microgreens in the post-harvest period. Also, the use of nano-silica increased the amount of total phenol (5.73%), antioxidant capacity (55%) and vitamin C (38.77%) compared to the control. In general, the results of this research showed that the pre-harvest application of silicon and nano-silica improves the nutritional characteristics of beet microgreens in the post-harvest period.

Due to scarcity of water resources, its negative effects on agricultural yield, and the need to ensure food security, it is necessary to provide effective strategies to improve management and water productivity in this sector. Accordingly, the present experiment has been carried out as a factorial based on completely randomized design during spring of 2019 in the research greenhouse of Shahid Bahonar University of Kerman. The research factors include 3 irrigation levels Fc100, Fc75, and Fc50 (100%, 75%, and 50% field capacity) as the first factor and two superabsorbent levels S0 and S5 (0 and 5 gr/kg soil) as the second factor, performed with five replications. The results show that the maximum yield (40. 23 ton/ ha) and water productivity (10.36 kg/) belong to FC100S5 treatment, increasing by 5.71% and 47.6%, respectively, compared to the values recorded in similar level of irrigation and non-superabsorbent polymer. The maximum value of total chlorophyll (25.12 mg/ml) are observed in FC100S5 treatment, which in turn increase by 19.44%, compared to the control. The maximum value of vitamin c occurs in FC100S0 treatment, being 18.27% higher than minimum recorded value. Finally, the results show that the difference between irrigation water production of cherry tomato in FC100S0 and FC75S5 has not been not significant, despite 25% reduction in field capacity moisture at FC75S5. According to the results of this research, the quadratic production function is recommended as the optimal function to estimate the mentioned traits in terms of application and non- application of super absorbent.

Tocopherols (Vitamin E) are an important group of organic compounds that realize vital activities in plant cells. They protect the photosynthetic system from photooxidation damages and prevent the lipid peroxidation of the chloroplast membrane. The presence of this plant organic compound in human nutrition is essential. In this research, six genes involved in the biosynthesis pathway of vitamin E including HPPD/ PDS1, VTE5, HPT/ VTE2, VTE3/ APG1/ IE35, TC/ VTE1, γ-TMT/ VTE4 and their products are identified in lentil plant using databases and bioinformatics software. After this identification, genes are implemented for breeding purposes of lentil through traditional breeding or modern biotechnology methods. According to the phylogenetic tree obtained by the MEGA 7 program, it was observed that most of these genes in the lentil have high homology to legume plants such as chickpea and alfalfa. In addition, the prediction of the presence of conserved domains revealed that the HPPD protein had two domains and one subdomain, and each of the proteins γ-TMT and VTE3 had only one conserved domain. Moreover, the results of the proteins description using ProtParam tool showed that the highest frequency with respect to the amino acids belonged to leucine, serine and glycine; by contrast, selenocysteine and pyrrolysine had the lowest frequency. The use of the DeepLoc-1.0 program predicted that only HPPD proteins were soluble in the cytoplasm, while five other proteins were located in the intermembrane space.

Aiming at finding a suitable treatment for maintaining the fruit quality and increase the shelf life of strawberry, effects of ascorbic acid and essential oil of Thymbra spicata were evaluated. Fruits were dipped in 10 and 15 mM of ascorbic acid and essential oil of T. spicata (400 and 600 ppm) for two minutes, and after drying at room temperature, were packed by cellophane in the polyethylene container and transferred to 4 °C. Some of the qualitative, quantitative and biochemical parameters were measured at 7 and 14 days after storage. Results of analysis of variance showed that there were significant differences among the treatments in most of the evaluated parameters. Strawberry fruits treated with ascorbic acid and essential oil showed lower weight loss and lower fruit browning, while they had higher marketability than control plants. Ascorbic acid and essential oil treatments also led to decreases in polyphenol oxidase activity, total phenol content and electro leakage, while the vitamin C content and antioxidant capacity were significantly higher than control plants. Generally, ascorbic acid (15 mM) and essential oil (400 ppm) compounds reduced fruit’s degradation during cold storage and these treatments have the potential to be used as practical postharvest treatments to retain the quality of strawberry fruits.

 Soybean is an important source of oil and protein human and animal protein. The main part of the growth period of this plant is in the summer, which is usually exposed to stresses such as heat, dryness and even salinity, and finally, there would negatively affect the growth and yield of these plants. It can be inferred that it may be possible to use external component to reduce the negative effects of stresses on plants and to increase yield and product quality.Considering the positive anti-tension properties of vitamins in group B and melatonin, it can be concluded that by applying these materials on soybean as a solution of positive effects, the growth and yield of physiological improvement, especially in summer conditions, can be obtained.Therefore, in this research, the effect of these materials on soybean on DPX cultivar, physiological and qualitative aspect was investigated at Shahroud University of Technology Research Field.

Treatments including melatonin foliar application (0, 0.1 and 0.2 mM) and vitamines B group (0, thiamine, riboflavin, niacin, pantothenic acid and pyridoxine 100 mg / L) were organized in factorial experiment on the basis of completely randomized block design in three replications.

The effect of melatonin and vitamin B on leaf area index, stem height, stem diameter, number of seeds per pod, 1000 seed weight, yield, oil yield, and protein content, leaf dry weight, stem dry weight, and reduction of leaf chlorophyll degradation was significant. The most effective on the traits were related to the combination of 0.2 mM Melatonin and Pantothenic Acid.The foliar application of these two substances reduced the chlorophyll degradation process and increased about 2 times the chlorophyll residue compared to the control.There were no significant differences in B vitamins in the two levels of 0 and 0.1 mM melatonin in terms of the effect on this trait and the effect of 0.2 mM melatonin was higher.There was a significant difference between the levels of B vitamins in terms of leaf area index. Pantothenic acid and pyridoxine were more effective than others.The lowest amount of seed oil yield was obtained in non-foliar application treatment with an average of 21 g / m2, which showed a significant difference with all the treatments. The use of B vitamins with a concentration of 0.2 mM of melatonin showed the highest levels of oil yield, the highest amount of which was related to the combination of Pantothenic acid and high concentrations of melatonin with an average of 106 g / m2. Conclusion In general, it can be concluded that the use of melatonin with vitamines B group can induce tolerance to the plant.Therefore, it is possible to use melatonin and vitamin B to increase the growth indices and soybean yield components.

In order to evaluate the effect of salicylic acid, glycine betaine and gamma_ aminobutyric acid foliar spray on anti-oxidant activity of enzymes and non-enzymatic agents of Carla (Momordica charantia L.) under water deficit stress, an experiment was conducted as split plots based on randomized complete blocks design with three replications at Research Farm University of Zanjan during 2017. The treatments consisted of three levels of irrigation (50, 75 and 100% field capacity) as the main plots and two levels of salicylic acid (2 and 4 mM), glycine betaine (50 and 100 mM), and gamma aminobutyric acid (GABA) (10 and 20 mM) plus control were used as sub plots. Based on the results, increasing of water deficit stress, significantly increased the activity of catalase, peroxidase and antioxidant activity of leaf, as well as total phenol and flavonoid content and antioxidant activity of fruit, but the amount of vitamin C decreased. The interaction of irrigation regimes with experimental treatments caused a significant increase in measured traits. The highest level of leaf and fruit antioxidant activity was obtained using 4 mM salicylic acid and 100 mM glycine, respectively, in 75% field capacity. Considering that in this study, plants treated with salicylic acid, glycine betaine and GABA in different irrigation regimes had higher enzymatic and non-enzymatic antioxidant activity than control plants, therefore it seems that application of these materials can be effective in producing Carla under water deficit stress resistance.

One of the most important characteristics of fruit crops is susceptibility to decay and quality reduction during storage life. Crops with higher antioxidant capacity are tolerant to stress and have greater nutritional quality and storage life. Hence, to investigate the antioxidant capacity of two grape cultivars Ghezel uzum and Red hosseini a factorial experiment with 3 replications was carried out as a Randomized complete block design. Results showed that the percentage of weight loss in Ghezel uzum cultivar was 1.5 fold greater than Red hosseini cultivar. Berry quality traits such as total soluble solids, pH, the amount of electrolyte conductivity and fruit taste index were increased while titrable acidity, carotenoid, chlorophyll a and b, anthocyanin, vitamin C, total phenol and the amount of antioxidant activity were decreased during storability in both cultivars. Ghezel uzum had more carotenoids than Red Hosseini (2.6 fold) but the extent of decreases in pigment concentration in Red hosseini was lesser than that of the other cultivar. In contrast the amount of antioxidant capacity (88.20% and 17.38% in skin and pulp, respectively), total phenol (204.4 and 2.11 mg 100gFw-1 in skin and pulp, respectively) and chlorophyll a and b (1.13 and 3.9 µg Kg-1, respectively) was greater in Red Hosseini cultivar compared to Ghezel uzum cultivar. It may be concluded that the Red hosseini cultivar has a greater capability in preserving its quality characteristics at the end of storage life, compared to other cultivar.

The effect of foliar application of zinc sulfate and seaweed on qualitative and quantitative characteristics of local Kermanshah cantaloupe (Cucumis melo L., Cantalupensis Group) cv. Kalak was investigated. After sowing seeds in the field, the plants were sprayed in three stages including the 4-6 leaf stage, flowering and after the fruit set. The experiment had a factorial design based on the randomized complete block design with 9 treatments including various concentrations of zinc sulfate (0.5 and 1 g L-1) and seaweed (0.5 and 1 g L-1) and was repeated three times. The results of analysis of variance showed that zinc sulfate at 0.5 g L-1 and seaweed at 1 g L-1 had significant effects on the weight, length and diameter of the fruit, the weight of the fresh fruit, fresh and dry weight of the plant, and fruit firmness. The highest amount of vitamin C was observed in zinc sulfate at 1 g L-1 and seaweed at 0.5 g L-1. The highest total seed weight was obtained in zinc sulfate at 0.5 g L-1 and seaweed at 1 g L-1. Foliar application of zinc sulfate and seaweed did not have a significant effect on total soluble solids (TSS). However, zinc sulfate at 0.5 g L-1 increased the amount of titratable acid (TA) in the fruit juice. The highest amount of the TSS/TA ratio of the fruits was observed in application of seaweed at 1 g L-1. Overall, the findings of the present study indicated that simultaneous application of zinc sulfate and low concentrations of seaweed extract has a significant effect on many qualitative and quantitative characteristics of “Kalak” Cantaloupe and can be recommended as a biofertilizer.

Background and Objectives Table grape (Vitis vinifera L.) is one of the most important horticulture crops in Iran. In some regions, due to excess water and good climate, the vegetative growth is more than normal. The canopy plays a key role in light energycapture via photosynthesis apparatus, water use as regulated by transpiration, and microclimate of ripening grapes. Canopy management is an important aspect of viticulture due to its effect on grape yields, quality, vigor, and the prevention of grape diseases. Where vineyards have access to a permanent and unlimited water source, irrigation can be managed so that water stress is imposed during certain periods of time to increase fruit quality and to control canopy. This study was conducted to investigate the effects of different levels of topping times and preharvest cut-off irrigation treatments on the qualitative and Quanitative characteristics of Askari grapes in Dena (Sisakht) region during 2013-2015.
Materials and Methods ‘Askari’ vines were 18 years old on their own roots, trained as a head system. The vines were spaced 2.5 × 3 m. They were pruned as spur pruning which left 60 buds (4-node spurs) on each vine. Vineyard had a drip irrigation system. Shoot topping done at 10th buds of the last cluster. An experiment was arranged as factorial that the first factor included different levels of topping dates with four levels (control, after fruit set, unripe stage and veraison stage), and the second factor involved the preharvest irrigation cut-off date treatments on four levels (Control, 70, 80 and 90 days after full bloom) in a randomized complete blocks design with four replications. Factors relating to the determination of the quality of fruit juices included %TSS, pH, TA%, vitamin C and TSS/TA ratio respectively. Also, bunch weight and yield were measured.
Results Results of the analysis of variance showed that the effect of topping and irrigation cut-off date treatment were significant on the TSS, TSS/TA, pH and Vit-C content (P≤0.01). But the interaction effects were significant only on the TSS/TA and Vit-C (P≤0.01). Finally, mean comparison showed that the highest vitamin C was observed at veraison stage and irrigation cutoff dates treatments at 80 and 90 days after full bloom.
Discussion In some of vineyards, high vigour vines also have too much canopy shading which is detrimental to the light microclimate and has also been shown to lead to increase of TA and decrease of TSS and TSS/TA ratio. Therefore, canopy manipulation is used successfully in grape production to balance the vegetative and reproductive growth of vines. Differences in vine water status before veraison has been shown to have no effect on the onset of veraison, while withholding water after veraison can delay the accumulation of soluble solids under severe water deficits. Certainly, light and temperature are the most important environmental conditions that impact the growth and quality of grapes and unshaded conditions affect better coloring and increase TSS/TA ratio.

This experiment was carried out based on a completely randomized design with three replications. Essential oils of Salvia macrosiphon, Hypericum perforatum and Zhumeria majdae at two levels: 250 and 500 ml/l and calcium chloride (2% and 4%) were applied on fruits that had been immersed in Botrytis cinerea spores, stored at a temperature of 4±1℃ and then kept for 16 days. Fruit decay (%), pH, fruit weight loss (%), TTS (%), total acid (mg/100 ml), tissue firmness ,color and changes in vitamin C were measured. Result showed that essential oils and calcium chloride had significant effect on fruit decay. Decay completely controled in all treated fruit expect Salvia macrosiphon (500 ml/l). The lowest and highest water loss was observed in calsium chloride (4%) and Salvia macrosiphon essential oil (500 ml/L) treatments, respectively. Tissue firmness was significantly higher in treated fruits than in control. Generally, calcium chloride (2% and 4%) and Salvia macrosiphon at 250 and 500 ml/l level showed the highest firmness. The lowest TSS (%) was shown in control fruits. Fruits treatment with calcium cheloride (2% and 4%) and essential oils of Zhumeria majdae at 250 and 500 ml/l level showed significantly higher vitamin C content. In general, all calcium chloride and essential oil treatments (except Zhumeria majdae at 250 ml/l) showed better color than the control. This research revealed that calcium chloride and Essential oils of the above three plants were effective in decay control and maintaining strawbery fruit quality during 16 days storage.

In order to study the effect of water deficit stress and foliar spray of Megafol on yield, fruit quality and water use efficiency (WUE) of tomto cv. Rio Grande, an experiment was carried out in a split plot based on randomized complete block design with three replications during 2015. Treatments consisted arrangement of three irrigation levels (starting irrigation at 100, 75 and 50% ETc) and 4 levels of Megafol (0, 1, 2 and 3 ml/L). The results showed that water deficit stress had significant effects on yield, fruit quality and WUE. Megafol treatment showed significant effects on yield, fruit firmness, fruit lycopene and WUE. The highest total soluble solids (2.41 %) and titratable acidity (TA) (2.09) was found at 50% ETc treatmen. Foliar application of 2 ml/L megafol was showed the highest value of TSS (2.29 %), TA (1.97%), lycopene (0.83 g/l), fruit per plant (37.94), fruit weight (59.32 gr) and WUE (21.78 kg/m3). Irrigation × foliar treatments interactions had significant effect on plant yield, fruits per plant and TA. Maximum fruit number (51.73) and plant yield (3278.43) was obtained with Megafol 2 ml/L under irrigation 100% ETc treatment. Also the highest TA was achieved in Megafol 1 ml/L under irrigation 50% ETc. According to the results, foliar application of Megafol 2 ml/l improved fruit yield under normal irrigation and deficit water stress and resulted in 16% inceease in WUE. 75% ETC treatment with reducing 16% of fruit yield, saved 25% of water as compared to 100% ETc treatment.

To evaluate yield and some quantitative and qualitative characteristics of tomato cultivars in Jiroft region and to determine suitable cultivar for this region, thirteen tomato cultivars were evaluated in an experiment using randomized complete block design (RCBD) with three replications during 2013-14. Cultivars consisted of Sun Seed, Rio Grande, Eden F1, Yagi, Kimia, Superchef, Calj N3, Yaghoot, Titan F1, Italian CH, Falat Ch, Falat Chef and Primo. In this study, traits of fruit yield, plant height, number of shoot and leaves per plant, days to flowering and harvest, fruit weight, length and diameter of fruit, total soluble solids (TSS), titratable acidity (TA) and vitamin C were recorded. Results of analysis of variance showed that the effect of cultivar on all traits was significant. Cultivars Eden and Kimia had the highest yield (61.62 and 58.78 ton ha-1, respectively). The results of evaluations showed generally that cultivar Kimia had better quantitative and qualitative characteristics and were determined as suitable cultivar for Jiroft region.