جستجوی مقالات مرتبط با کلیدواژه "total soluble solid" در نشریات گروه "کشاورزی"

Physalis peruviana L. is a short perennial shrub that is a member of the Solanaceae family. These fruits have many benefits for human health because of their nutritional and bioactive compounds (vitamins (A, B, C and K), essential fats and etc.) and reduced the risk of diseases such as cancer, malaria, asthma, hepatitis, dermatitis and rheumatism. Therefore, it has received special attention for cultivation all over the world. Increasing crop production and mitigating abiotic stresses are major challenges under extreme climatic environments and intense farming activities. Crop management strategies such as deficit irrigation can decrease soil evaporation, runoff, and plant transpiration, and increase water use efficiency (WUE) and water conservation. In addition to these practices, organic input, which includes the application of organic materials such as compost and humic substances, is an additional strategy that increases soil water retention and can potentially improve plant WUE. Water is crucial for agriculture and needs to be used effectively due to climate change and drought in Iran. For this reason, to adapt to water deficit scenarios, deficit irrigation applications are increasing in importance. Water availability is expected to be a growth limiting factor that would affect fruit yield in Physalis peruviana due to reduced flower set and elevated floral abscission rate.

In order to investigate the effect of humic acid on physiological characteristics, yield and fruit quality of Physalis peruviana under deficit irrigation conditions, a split plot experiment based on randomized complete block design with three replications was conducted during 2021. Treatments consisted arrangement of three levels of irrigation (starting irrigation at 100, 80 and 60% ETc (crop evapotranspiration)) and three levels of humic acid (0, 1.5 and 3 kg ha-1). The seeds of Physalis peruviana were sown in seedling trays contain peat moss. The seedlings were grown under normal conditions (25±2 °C/day and 20±2 °C at night with 60-65% RH). Plant height, total chlorophyll, fruit yield per plant, total soluble solid content, titratable acidity, vitamin C content and water use efficiency were measured. Statistical analyses were performed with SAS V9.3, and means comparison were separated by Duncan’s multiple range tests at p < 0.05.

Results and Discussion :

The results showed that deficit irrigation significantly reduced growth, fruit yield, vitamin C and increased water use efficiency (WUE) and Total soluble solid content of Physalis peruviana. The soil application of humic acid significantly increased total chlorophyll, fruit quality and yield, and decreased leaf electrolyte leakage under normal and deficit irrigation, thus, the deficit irrigation 60 ETc% decreased the plant height by 18.6% and the fruit yield by 22.2% compared to irrigation 100 ETc%. The maximum plant length (200.3 cm), total chlorophyll content (2.42 mg g-1FW) and fruit yield (4793.3 kg ha-1) were observed in plants treated with 3 kg ha-1 humic acid under 100% ETc irrigation. The highest value of total soluble solid (12.6 B°), antioxidant activity (90.06 %) and WUE (1.23 kg m-3) were obtained with 3 kg ha-1 soil application of humic acid under deficit irrigation 60% ETc. The application of 3 kg ha-1 humic acid under 100 and 80 %ETc irrigation increased the fruit yield by 25% and 4%, respectively, compared to the control plants (non treated with humic acid) under irrigation100 ETc% and under deficit irrigation  60 ETc%, with decreasing 11% fruit yield, water consumption was saved by 40%. Soil and crop management practices that alter plant water and nutrient availability could affect the processes of crop evapotranspiration and WUE, which can influence the yield and fruit quality by changing the internal nutrient and water balance. Incorporating organic matter within a crop growth system either as leaf spray or soil mix is a complementary strategy to improve crop growth and WUE. By inducing antioxidant enzyme activities, HS could assist plants in stomata functioning, thereby closing stomata more efficiently under drought stress, which results in plant water conservation. The reason of the difference between WUE values probably appeared due to the differences on Physalis peruviana yield. WUE showed an upward trend with an increasing in irrigation.

Study results suggest that soil application of humic acid with increasing vitamin C, TSS and TA, improved fruit quality. According to the results, application of 3 kg ha-1 humic acid is suggested to improve fruit yield and quality of Physalis peruviana under normal and deficit irrigation conditions.

Strawberry (Fragaria × ananassa Duch.) is one of the most popular soft fruits worldwide. It is a rich source of health promoting compounds such as essential macro/micro-nutrients, polyphenols, anthocyanin, vitamins and amino acids, while showing a high antioxidant capacity. Preharvest applications of calcium lactate and potassium sorbate have shown to be promising as a tool to improve the quality and extend the shelf life of various fruits. To our knowledge, however, little information is available regarding the effect of calcium lactate and potassium sorbate on strawberry fruits. Thus, the objective of the present study was to determine the effect of foliar application of calcium lactate and potassium sorbate on important quality characteristics and antioxidant properties of ‘Armas’ strawberries.

This research was performed at a commercial orchard on 2-year old strawberries in Marivan, Iran in 2015. The experiment was arranged as factorial based on randomized complete block design with two factors and four replications. The first factor included different levels of calcium lactate (0, 0.5 and 1%) and the second factor included different levels of potassium sorbate (0, 0.5 and 1%). Foliar spraying was performed in three stages: three weeks before commercial harvesting, at initial coloring, and one week before harvest. Fruit were harvested at commercial maturity and immediately transported to the laboratory at University of Zanjan and subjected to physicochemical analysis. Differences among means of data were analyzed by Duncan’s test at p ≤ 0.05 (n = 3). All statistical analyses were performed with SAS version 9.4.

The results showed that the combination of calcium lactate and potassium sorbate (0.5 Percent concentration) treatment significantly (P £ 0.01) increased the total anthocyanin content of the whole fruit, reuslting into further attractive fruit color and market than the control. It also increased antioxidant properties up to a level of 57.07%. On the other hand, the application of this treatment (calcium lactate and potassium sorbate 0.5 Percent) significantly increased the total flavonoid content, total soluble solids, flavor index (1.1 Percent) and calcium lactate (1 Percent). Potassium sorbate increased total phenol, total acidity, and fruit acidity significantly compared to other treatments and control (P £ 0.05).

In general, the results of the present study showed that a preharvest application of calcium lactate and potassium sorbate increased firmness, nutritional quality, and antioxidant potential of strawberry fruits. Thus, the use of these two materials is recommended to improve the qualitative and antioxidant properties of strawberry fruit.

Baby corn is a premature ear of maize that is harvested as dehusked vegetable corn at 2-3 days after silking before fertilization. No enough attention has been paid to this kind of maize in the literature. In order to investigate the effect of planting density and pattern on yield and some qualitative and morphological traits in baby corn hybrid KSC403su a field experiment was conducted at College of Agriculture, Shiraz University, Shiraz, Iran in 2014. The treatments were plant density at four levels: 100, 125, 150 and 175 thousands plant ha-1 and three planting patterns: one, two and three rows which arranged in factorial based on a randomized complete block design (RCBD) with three replications. The results showed that yield, solar radiation, total soluble solid (TTS) and a majority of morphological traits of baby corn were significantly affected by the treatments and their interactions. With increasing of the number of rows and plant density, leaf area and  plant height were increased, while the number of tillers per plant, number of ears per plant, husked and dehusked ear yield, husked and dehusked ear weight and ear diameter were decreased. The highest husked and dehusked ear yield were obtained in 150 thousands plant ha-1 and single row planting pattern with average of 1834 and 9128 Kg ha-1, respectively. In general, one row planting pattern at 150 thousands plant ha-1 were considered as the most suitable treatments and could be suggested for achieving acceptable yield and appropriate quality.

  Sweet pepper (Capsicum annuum L.) is a worldwide used vegetable, which is an excellent source of ascorbic acid and has high antioxidant capacity against oxidative damage caused by free radicals. Ascorbic acid (AsA) is a water-soluble vitamin that plays a key physiological role in scavenging reactive oxygen species (ROS), and enzyme cofactor. In recent years, the application of exogenous AsA has received much attention for use as a biologically safe compound for postharvest quality maintenance of many horticulture crops. Calcium is an essential micronutrient that plays a vital role in maintains cell wall stability, integrity and determining the fruit quality. To our knowledge, however, little information is available regarding the effect of ascorbic acid and calcium lactate on pepper fruits. Thus, the aim of this study was to investigate the foliar application of ascorbic acid and calcium lactate on growth, yield and fruit quality of sweet peppers. To study the effect of foliar application of calcium lactate (Ca) and Ascorbic acid (AsA) on growth, yield and fruit quality of sweet pepper, the field experiment was carried out from June to September 2016 at Research farm of faculty of Agriculture, at the University of Zanjan, Iran. Pepper plants (cv. California Wonder) were cultivated by applying conventional farming practice for growing in open air conditions. 210 plants (30 plants for each treatment) were selected for uniform size and fruit load, and were sprayed three times (0, 15, 30 days after full bloom) with an aqueous solution containing different concentrations of Ca (0, 0.5, 1 and 1.5 g L-1) and AsA (100, 200 and 300 mg L-1). Each treatment was carried out with three replicates. Pepper fruit were harvested at commercial maturity stage, and transferred to the laboratory on the same day. Leaf area was recorded whit measurement leaf area (DELTA-T DEVICEC LTD, ENGLAND). After fruit harvested, plant length was measured. Fruit was weighted after harvest to determine mean fruit weight. The fruit number per plant and fruit yield per plant was measured to determine of total yield. The total yield expressed in kg ha–1. Flesh firmness was determined with penetrometer (model Mc Cormic FT 32), using an 8 mm penetrating tip. Results were expressed in kg cm-2. The pH values of solutions were monitored with pH meter. TSS was measured in the extract obtained from three fruit of each replicate with a digital refractometer Atago PR-101 (Atago Co., Ltd., Tokyo, Japan) at 20◦C. Total ascorbic acid content was expressed as mg per 100 g of juice. Antioxidant activity was measured using the free radical scavenging activity (DPPH) and calculated according to the following formula:  RSA%= 100(Ac-As)/Ac. Statistical analyses were performed with SPSS software package v. 20.0 for Windows, and means comparison were separated by Duncan’s multiple range tests at p < 0.05. The results showed that foliar application of AsA had significant effects on growth and fruit yield. The highest fruit yield (897.1 g plant-1) was achieved at 300 mg L-1 AsA that had no significant difference with 200 mg L-1 AsA. Foliar application of AsA markedly increased vitamin C content, and also the highest value of total soluble solid (5.7 °B) was recorded from 300 mg L-1 AsA. Ca had no significant effects on growth and fruit yield but significantly improved fruit firmness. The highest fruit firmness (2.13 and 2.16 kg cm-1) was obtained from 1 and 1.5 g L-1 Ca. The maximum antioxidant activity was achieved with application of 300 mg L-1 AsA and 1.5 g L-1 Ca. The fresh sweet peppers were an important source of ascorbic acid for human consumption. AsA significantly increased the amount of vitamin C in the plum and sweet pepper fruits. Foliar treatment of Ca increased vitamin C content. Increasing vitamin C content in fruits after treatment with Ca could be related to inhibiting action of calcium on the activities of ascorbic acid oxidase that use ascorbate as a substrate. The results indicated that treatment of Ca produced fruits with higher firmness compared to control and other treatments. Firmness and resistance to softening can be increased by the addition of Ca, due to interaction of calcium with pectate acid in the cell wall to form calcium pectate and retarding polygalacturonase activity. Differences in the percentage of TSS content at the time of harvest indicated the AsA and Ca effects on carbohydrate accumulation in fruits, which had different potential on respiration rates and consequently storability of plants. The exogenous application of AsA and Ca in sweet pepper plants indicated that treatments had significant effects on ascorbic acid content of sweet peppers. The antioxidant activity has positive correlation with total phenolic content, flavonoids and content of ascorbic acid. The results of our research indicated that per-harvest foliar application of AsA increased plant growth, fruit number and weight. Also, AsA and Ca treatments improved fruit quality attributes including vitamin C, fruit firmness, TSS and antioxidant activity. These results suggest that AsA and Ca treatments, especially AsA 300 mg L-1 and Ca 1.5 g L-1, may be proposed to improve fruit quality.

In order to evaluate the effect of irrigation and pruning on Yaghooti grape, an experiment was carried out in Sarpole Zehab. This study was conducted in a randomized complete block design with 5 level of pruning severity (two, three, four, five and six buds) and irrigation (reduced and full) with four replications using six years old Yaghooti grape in 2010. The results showed that there as a significant difference between pruning and irrigation treatments in terms of fruit yield, panicle number, cluster weight, berry weight and fruit quality. The highest fruit yield per plant (5.15, 5 and 5.35kg) and per hectare (12.88, 12.41 and 13.38) were obtained at four, five and six buds pruning under well-watered plants. Cluster production significantly increased by reducing pruning severity from two to six buds. Cluster weight was significantly high at four buds pruning under well irrigation conditions in compared to the other treatments. Total soluble solids decreased in six buds pruning severity comparied to the other treatments. Generally, fruit production was significantly affected by pruning severity and irrigation conditions in Yaghooti grape. According to the results of qualitative and quantitative traits especially yield, cluster weight and fruit soluble solids, remaining four buds and regular irrigation is recommend for Yaghooti grape.

Sweet cherry fruit due to high water content and respiration rate is rotten in post-harvest period and hence has a short storage life. So, reducing of respiration rate and delaying of senescence process are required for increasing of storage life. Gamma amino butyric acid (GABA) is a non-protein amino acid with low content in the cell in normal state. No study has taken into account the effect of GABA on the storage life of sweet cherry fruit and also, increasing of shelf life by natural compounds seems essential to maintain the quality. Therefore, this study was conducted with the aim of improving the post-harvest quality of sweet cherry fruit, increasing biochemical and antioxidant properties and improving fruit appearance using GABA with the purpose of replacing it with synthetic chemicals. Fruits of sweet cherry cv. Tak Daneyeh Mashhad were harvested at commercial maturity from a commercial orchard in Urmia (Iran) and transported to laboratory immediately. GABA was used in three concentrations (5, 10 and 20 mM). Titration method was used for determination of Titratable acid (TA) and pH was determined by pH meter. TSS was determined by refractometer. Total antioxidant capacity was determined by ferric ions reducing antioxidant power assay (FRAP). Total phenolic content was determined by Folin ciocalteu method and total flavonoid content was determined by the aluminum chloride colorimetric method. The results showed that TA content remains constant with treatment of GABA during storage. GABA treatment leads to an increase in total antioxidant activity, total phenol, total flavonoid and activity of catalase and guaiacol peroxidase enzymes in the treated fruits compared to control fruit after 30 days of storage. The pH value in treated fruits compared to untreated fruits was decreased during storage. Also, GABA at 10 mM level compared with other concentrations had the highest effect on total antioxidant capacity after 30 days of storage. The increasing of organic acids in treating fruits can be probably due to increasing of antioxidant capacity by GABA treatment, hence the damage to membrane was prevented and the organic acids were used less frequently. Treatment of fruits with GABA decreased the pH during storage, which may be due to its role in reducing of respiration rate in harvested fruits. The mechanism of the effect of GABA on increasing of total phenol and flavonoid content may be due to stimulating the production of Phenylalanine ammonia lyase (PAL) which can trigger phenylpropanoid pathway and hereby, syntheses of phenolic compounds such as flavonoids compounds were occurred. Catalase is one of the key enzymes to protect the cells and cause the conversion of hydrogen peroxide to water and oxygen. Therefore, probably the GABA treatment via the increasing the antioxidant system such as catalase leads to scavenge free radicals thereby protecting plants against oxidative stress.

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.

In order to investigate the quality and shelf life of mango, a factorial experiment was conducted based on a completely randomized design with three replications, in Hamedan Science and Technology Park, in 2015. Treatments consisted of four levels of chitosan (0 (control), 0.5, 1 and 2%) and storage duration of 0 (control), 8, 16, and 24 days. The results showed that chitosan could improve the physical and biochemical properties of mango. Changes in tissue firmness and physiochemical indices including weight loss, pH, TSS, titratable acidity, ascorbic acid, and phenol contents were examined. The results revealed that decline in fruit firmness was effectively inhibited by chitosan coating. After 24 days of storage, maximum firmness was observed after the application of 2% chitosan (5.3) and the lowest was obtained from the control (3.2). Also, the chitosan coating effectively inhibited decline in fruit weight, pH and ascorbic acid. During the period of storage, there was a decrease in Total soluble solids (TSS), but no significant difference was observed among the treatments at the end of the storage period. Phenol content first increased and then decreased at the end of the storage period. The maximum amount of phenol was observed in 1 and 2% chitosan, while the minimum amount was obtained from the control.

Introduction. Citrus is one of the most commercially important horticultural crops grown in tropical and sub-tropical regions of the world. They are classified as non-climacteric fruits. Harvesting date and storage can influence citrus fruit quality and shelf life. In Iran, some members of citrus family including sweet orange and mandarin are produced as an export crop, so research on fruit quality and storage life is needed. There is no available scientific literature regarding the effect of harvesting date and storage duration on retaining the postharvest physicochemical properties of Kinnow mandarin under cold storage. The main objective of the present study was to evaluate the effect of harvesting date and storing time on shelf life and quality of Kinnow mandarin fruits under Jiroft weather conditions.
Materials and Methods. Investigations were carried out on mandarin (Citrus reticulata) cv. Kinnow grafted on sour orange rootstock in an orchard located in Jiroft and Kahnooj Agricultural Research Center, Jiroft, Iran. Fruits were harvested on 6th December, 21th December, 5th January, 20th January and 4th February. After cold storage for 30-90 days at 4-6 °C, the fruit was analyzed for quantitative and qualitative characteristics including weight of fruit, peel, meat, pulp and juice, fruit weight loss, pH, total soluble solids (TSS), titratable acidity (TA) and TSS/TA. Experiment was arranged in a split plot based on randomized complete block design (RCBD). Data analysis and similarity coefficient (Pearson's method) were performed using SPSS.16 software, and means comparison was performed by using Duncan's multiple range test at 1 and 5% probability levels.
Results and Discussion. The results showed that the interaction effect of harvesting date and storage period on the weight of the fruit, meat, pulp and juice and TSS, TA and TSS/TA was significant at 1% probability level. Weight of harvested fruits from 6th December to 5th January was constant, but fruits harvested on 20th January and 4th February were heavier as much as 12.5 and 14.3 percent, respectively, compared to 6th December. Fruit weight loss increased along with the increase in storage time duration, so that mean fruits weight loss percentages were 3.5 and 16.5 at 30 and 90 days of storage, respectively, due to continued transpiration of the fruits after harvesting. As a result of transpiration, water enters into the atmosphere through the pores existing on fruit surface. The greatest fruit weight (121.8 g) was recorded for combination of harvesting on 20th January and 30-day storage. Fruits harvested on 20th January and 30-day storage had higher meat and pulp weight (89.6 and 52.3 g, respectively) and a significant correlation coefficient was detected between them. Changes of fruit juice pH at different stages of fruit ripening and storage times did not follow a fixed pattern, though pH slightly increased in some cases during storage, which can be due to oxidation of citric acid during storage. The maximum TSS was recorded for harvesting on 5th January and 90-day storage (11.7 °Brix) as well as 4th February and 60- and 90-day storages (11.8 °Brix), while the minimum TSS was observed on 6th December and 30-day storage (8.7 °Brix). The results exhibited that TSS content of fruit juice increased when storage period increased, which was possibly attributed to the hydrolysis of starch and increase in sucrose content. However, increase in TSS during storage is not always directly related to changes in the simple sugar content of fruit. During storage and maturation of the fruits on the tree, TA reduced due to the use of citric acid in respiration. Taste index (TSS/TA) in fruits harvested at full maturity was greater than that in fruits harvested in the fall. Besides, TSS/TA increased during storage, so that the highest and lowest average TSS/TA ratios were related to harvesting on 4th February and 30-day storage as well as 6th December and 30-day storage, respectively. According to the results, fruits did not reach full maturity until 5th January under Jiroft weather conditions.
Conclusion. Postharvest quality and shelf life of Kinnow mandarin fruits were affected by harvesting date and storage duration. Delay in harvest resulted in an increase in fruit weight, TSS and TSS/TA. TSS and TSS/TA were higher when fruits harvested on 4th February. Fruit weight loss increased when the storage period increased.. Overall, 4th February is the best date to harvest Kinnow mandarin fruit in Jiroft.

In order to study the effects of chitosan and hot water treatments on storability and fruit quality of sweet pepper "Paks", an experiment was conducted as a factorial design in the base of CRD with three replications.Fruits were treated withchitosan at four levels (0, 1, 1.5 and 2 percent) and hot water at 20 and 45ºC (dipping for 2 min time) and 60ºC (dipping for 2o sec time), then stored for 12, 24 and 35 days at 8°C and 98% RH in refrigerator. The results showed that the quality and vitamin Ccontent of fruits decreased during storage. Coating of pepper with chitosan significantly delayed loss of TSS, firmness, vitamin C, weight losses and fruit quality. Pepper coated with 2% chitosan had the highest effect on keeping fruit quality. Hot water had significant effect on fruit quality. Water with 45°C as hot water treatment improved firmness, titrable acidity, vitamin C, visual quality and activity of catalase and peroxidase enzymes. Heat damage was observed on fruit dipping at 60°C. According to the results, treatment of 2 percent chitosan with hot water 45°C had the best effect on the studied parameters.

Recently, strawberry growers have been mostly interested in growing cultivars for the fresh market because of its profitability, but on the other hand it requires more complicated technologies and well-educated workers. High quality of the fruit for the fresh market is an important factor attracts customers and determines their choice and prices. Fruit production cost for the fresh market needs to be calculated and efficient methods and technologies also should be taken into consideration. New environmentally friendly mineral-organic fertilizers can improve fruit quality and yield of dessert strawberry cultivars. The desired effects was obtained through the activity of fertilizer’s components, which very often belong to different groups of natural hormones, elicitors, vitamins, flavonoids, amino acids, etc. Numerous breeding programs have been aimed at improving strawberry taste and disease resistance. Three major components of fruit organoleptic quality are flavor, sweetness, and acidity. Several studies have been devoted to strawberry aroma. Fruit with intense flavor also have high titratable acidity and high soluble solids. Numerous studies have addressed strawberry sweetness and acidity. Fruit soluble solids, sugars, titratable acidity, and organic acids at maturity are quantitatively inherited. Moreover, there appears to be genetic variations for these fruit quality traits. Numerous biochemical changes are observed during strawberry development and especially during fruit ripening. The major soluble constituents of maturing and ripe strawberries are soluble sugars and organic acids. The major soluble sugars in strawberries are glucose, fructose, and sucrose. The major organic acid is citric acid. This acid contributes greatly to fruit titratable acidity, which declines gradually during fruit development. The sugar/ organic acid ratio is a major parameter of strawberry taste. Brassinosteroids (BRs) are a class of poly hydroxyl steroids, which have been recognized as a class of plant hormones. These were first explored when Mitchell et al. (1970) reported that cell division and elongation were promoted by the treatment of organic extracts of rape (Brassica napus L.) pollen. Brassinolide (BL) was the first isolated brassinosteroid when Michael et al. (1979) isolated the biologically active molecule. Researches showed that brassinosteroids are essential for many physiological functions in plants, however little is known concerning where and when they are synthesized. In young tomato seedlings BR synthesis activity was observed mainly in apical and root tissues undergoing expansion. In flowers, synthesis activity was observed in the pedicel joints and ovaries, whereas in the fruits it was strongest during early seed development and was associated with the locular jelly and seeds. Quantitative measurements of endogenous BR indicated intense biosynthesis in developing tomato fruits, which were also found to contain high amounts of brassinolide. Moreover, brassinosteroids stimulate cell elongation and cell division, and BR has a specific effect of differentiation. Underling physiological pathways include modification of cell wall properties, effects on carbohydrate assimilation, allocation, and control of aquaporin activities. Brassinosteroids apparently coordinates and integrates diverse processes required for growth, partly via interactions with phytohormones setting the frame for BR responses. The aim of present study was investigation of the role of brassinosteroid on qualitative characteristics improvement of strawberry fruit.
In this research the effect of different concentrations (0, 0.25, 0.50, 0.75 and 1 mgl-1) of brassinosteroid sprayat different stages of strawberry growth (30 days after planting, first blooming, green fruit, and pink fruit) on some qualitative characteristics of the strawberry Paros cultivar was considered. This experiment was conducted asfactorial on a randomized complete block design with 4 replications in greenhouse conditions. Parameters such as total soluble solid, inducing sugar, titrable acidity, anthocyanin, phenol, fruit dry weight, fruit water and vitamin C were measured after….
Results showed treated plants by brassinosteroid, compared to control, improved fruit qualitative characteristics. So, brassinosteroid application increased total soluble solid, inducing sugar, titratable acidity, anthocyanin, phenol, dry weight, vitamin C.The best effective treatment and the best spraying time was brassinosteroid at 1 mgl-1 in pink fruit stage, respectively for qualitative characteristics improvement. Because, Brassinosteroid growth induced has been related to increase in RNA and DNA content, polymerase activity, protein synthesis carbohydrate fraction, reducing sugars, non-reducing sugars and starch. The yield increase in fruit trees may be related to improvement in the assimilation efficiency of photosynthetic carbon of the sprayed trees. The brassinosteroid application in wheat and mustard plants stimulated photosynthetic activity expressed by acceleration in CO2 fixing, increase protein biosynthesis and in mustard, increased photosynthetic rates that were directly related to growth and seed production. In accordance, researchers explained that BRs have been shown to enhance tracheary element differentiation, stimulate membrane hyperpolarization and ATPase activity, promote ethylene biothynsesis, control microtubule orientation and alter the mechanical properties of cell walls. In addition, brassinosteroid treatment greatly stimulated accumulation of photosynthates in the treated internode. This suggests a possible mobilization role for BR in the intact plant. As well as, in persimmon, grapevine and citrus, reported that BR compound showed, the practical effects for fruit setting. While, showed that brassinolide increased fruit weight and sugar content of oranges. In passion fruit orchards, brassinosteroid increased fruit number of plant and in turn yield per hectare and soluble solids content was 1° Brix greater than the control.
From this study, it is evident that the application of plant biostimulants such as brassinosteroid significantly improved qualitative characteristics. So, brassinosteroid application increased total soluble solid, inducing sugar, titrable acidity, anthocyanin, phenol, dry weight, vitamin C and effective treatment and best spraying was brassinosteroid at 1 mgl-1 at pink fruit stage for qualitative characteristics improvement.

In order to study the effects of foliar application of NAA and plant thinning on growth, yield and fruit quality of melon genotype Khatooni, the experiment was conducted in a randomized complete block design with three replications at Research field of Faculty of Agriculture, University of Zanjan. Treatments consisted of foliar application of NAA at three levels (25, 50 and 100 mg.L-1 at 4-6 true leaf and fruit set stages), pruning (pruning against nonpruning) and plant thinning. Treatment with NAA increased the total soluble solids content of fruit. An obvious gradient of TSS was detected, ascending from pedicel to umbilicus part of mesocarp. The maximum leaf area, fruit width and mesocarpe thickness was observed in NAA (100 mg.L-1 at fruit set stage). NAA caused a significant decrease in time to ripening. Among the treatments, the highest number of fruits per plant and total yield was recorded by using NAA (50 mg.L-1 at 4-6 leaf stage). Also maximum mean fruit weight and marketable yield was obtained in plant thinning treatment. According to the results, foliar application of NAA (100 mg.L-1 at fruit set stage) can be proposed instead of plant thinning practice that require too much time and labor for the farmers.

In order to investigate the influence of humic acid spraying on trees on shelf life and to maintenance of quantitative and qualitative characteristics of ‘Granny Smith’ apple, an experiment based on completely randomized block design was conducted in khoramdareh postharvest physiology laboratory of University of Zanjan. The humic acid spraying was conducted in four concentrations of 0 (distilled water), 5, 10 and 15 mg l-1 on 8 year-old ‘Granny Smith’apple trees grafted on MM106 rootstock. Spraying was conducted 2, 4 and 8 weeks after full bloom stage. Fruits of trees treated stored in 0±0.5°C with 90±5% relative humidity for six months. Fruit weight loss, fruit firmness, pH, total soluble solid (TSS), titrable acid (TA), total sugar (TS) and ascorbic acid content (vitamin C) were measured every two months. The results showed that, during the storage, fruit weight, fruit firmness, TA and ascorbic acid decreased. The maximum and minimum amont was belong to 10 and 15 mg l-1 humic acid and control treatment in the third stage of sampling (sixth months). Meanwhile, total soluble solid, pH and TA increased in the storage. According to the obtained results, it can be concluded that humic acid spraying had influence on shelf life and quantity and quality characteristics of ‘Granny Smith’ apple during storage. Therefore, to maintain postharvest quality of ‘Granny Smith’ apple spraying of humic acid with concentrations of 10 and 15 mg l-1 on trees is recommended.

In this study, effect of CaCl2 treatment and spraying time were studied on quality, mineral composition and shelf life of apricot (Prunus armeniaca cv. ‘Jahangiri’). The experiment was conducted in a randomized complete block design with seven treatments at the experimental orchard of Horticultural Research Station of Kamalabad in Alborz (Karaj) province, Iran, during two years (2010 and 2011). Treatments were control tress (spraying with distilled water) and two concentrations of calcium chloride (0.5 and 1%), in three time (30, 38 and 46 days after full bloom). Fruits were stored at 0°C with 93 to 95% relative humidity. Fresh weight and dry weight, flesh fruit firmness, fruit volume, pH, total soluble solid (TSS), mineral concentration (Ca, Mg, N, K and P) were measured five times (at harvest time, 1st, 2nd, 3rd, 4th week of shelf life). Also, fruit wet weight loss was recorded at week 4 and compared with the fruit weight at harvesting. The results indicated that pre-harvest calcium chloride spraying of fruits had significant effect on all of studied parameters. Spraying with different concentrations of calcium chloride increased shelf life of apricot until 10 days with maintaining of quality. The best spraying time for increasing of fruit quality can be applied between 1 and 1.5 months after full bloom.

In order to evaluate the effect of different concentrations of postharvest salicylic acid and calcium chloride on shelf life، quality characteristics and antioxidant activity of peach fruit cv. Amesden، an experiment was conducted as factorial based on randomized completely design with three replications. Fruits were harvested at the commercial ripening stage، and fruits were immerged in different concentrations of salicylic acid (1 and 2 mM)، calcium chloride (1. 5 and 3%)، combined salicylic acid and calcium chloride (1-1. 5، 1-3، 2-1. 5 and 2-3)، and distilled water (control) for 5 min، then fruits were packed in boxes with polyethylene cover and stored at 4°C with 80-85% relative humidity for 35 days. The changes in weight loss، fruit firmness، rot percentage; pH، total soluble solids، titratable acidity، ascorbic acid and antioxidant activity were estimated in 0 and 35 days during storage. The results showed that the weight loss، rot percentage، pH and total soluble solids significantly increased، while the fruit firmness، titratable acidity، ascorbic acid and antioxidant activity significantly decreased at the end of storage period. The salicylic acid and calcium chloride treatments significantly reduced the weight loss and maintained their firmness. In this condition، the highest of titratable acidity، ascorbic acid and antioxidant activity were observed in treatments of salicylic acid and calcium chloride، while the lowest of total soluble solids and rot percentage was showed in treatments of salicylic acid and calcium chloride than in the control treatment. Also، combined treatment (salicylic acid + calcium chloride) had an important effect in relative to each treatment separately. The data indicated that the use of salicylic acid and calcium chloride may be introduced as an effective and successful strategy in postharvest technology of the peach.

Effect of ethephon foliar spray on berry anthocyanin contents and quality of grape (‘Beidaneh Ghermez) was studied, using a split plot design. Four ethephon levels [0 (control), 100, 200 and 300 ppm] were sprayed at two growth stages T1 (10-30% berry veraison) and T2 (50-70% berry ripening). Results showed that ethephon significantly increased berry anthocianin content, berry weight and total soluble solid (TSS). Meanwhile, there were not any significant differences among titrable acidity (TA), pH, test index (TSS: TA) and berry firmness compared with control treatment. Also, there was not any significant difference between applications of ethephon times on measured parameters. Ethephon spraying had more impact on increasing anthocianin in berry of ‘Beidaneh Ghermez’ and improved color. According on obtained results it can be said, 300 ppm concentration of ethephon in early ripening time (T1) had best effect. Also, ethephon spraying not only increased color and total soluble solid content also accelerated fruit maturity and ripening.

Glycine betaine and proline are two osmolytes that are accumulated in plants in response to environmental stress. To investigate the effect of these compounds on photosynthesis parameters, fruit yield and quality of grape under drought stress, a factorial experiment based on randomized complete block design with four replications was performed on four ownrooted grape cultivars (‘Khushnav’, ‘Peykani’, ‘Perlette’ and ‘Flame Seedless’) at Takestan National Grape Collection Station. Stressed vines were irrigated by 70% of the required water. Grapevines were sprayed at four growth stages (before flowering, flowering, sour cluster and veraison) with proline (10 mM) and glycine betaine (15 mM). Proline and glycine betaine application increased stomatal conductance, net photosynthesis and fruit yield under drought conditions, in comparison with control. However, fresh edible quality of fruit was not desirable due to lower TSS and higher TA. Among the four studied cultivars, ‘Khushnav’ and ‘Peykani’ had the highest ripening index (TSS/TA), but the amount of fruit yield was similar in four cultivars.

This experiment was carried out to elucidate the importance of leaves on vase life of three greenhouse rose cultivars in Khorramabad, Iran, during 2010. Keeping leaves on cut stem or defoliation and inclusion of 0 or 4% sucrose in vase water in three rose cultivars (Coffee Break, Polar Star and Full House) were arranged factorially based on a randomized complete blocks design. Results showed that defoliation significantly increased water balance, relative fresh weight and vase life. Inclusion of 4% sucrose in vase water of cut stems having leaves caused leaf damage and decreased water uptake and water loss so that the trends of water uptake and water loss of these stems were the same as defoliated cut stems. Inclusion of sucrose while increasing total soluble solid in petals did not show any positive effect on vase life. Defoliated flower stems in vase water with 0% sucrose showed maximum vase life (11.33 d), following defoliated stems stored in 4% sucrose (10.27 d). Cut stems having leaves with 0 and 4% sucrose (8.87 and 9.07 d, respectively) showed minimum vase life.

The following study was conducted at the Research Station of Horticultural Sciences (University of Tehran، Karaj) to investigate the effect of different irrigation levels and fruit site on the stalk upon the traits of: sink-source relationship، yield، and fruit quality in two Iranian melon cultivars. The statistical design was a split split-plot of three replications. Treatments consisted of a factorial arrangement of three irrigation levels (starting irrigation at -50، -65 and -75 cbar)، four thinning levels (retainment of fruit at the second، fourth or seventh node of each of two secondary stems vs. control plants undergoing no thinning) along with two cultivars of Iranian melons (Zard Jalali and Suski Sabz). Results revealed that water stress reduced fruit weight as well as yield. The lowest fruit weight and yield were obtained in the case of severe stress treatment (-75 cb). Thinning methods exerted significant effects on mean fruit weight and yield. The highest values having been obtained from fruits kept on the 7th node treatments. The cultivar “Zare Jalali” bore higher fruit dry matter (%) and benefited from a higher flesh firmness as compared with “Suski Sabz”. The first water stress treatment increased Total Soluble Solids (TSS) content. Retainment of fruits on the 7th node resulted in the highest level of TSS (10. 77%). Water stress resulted in a significant shortening of the ripening time for about 7 days. Retainment of fruit on the 2th node caused earlier ripening of the fruit. Water stress reduced photoassimilate production and improved fruit sweetness. Also، water stress and thinning affected fruit ripening.