جستجوی مقالات مرتبط با کلیدواژه « سفتی بافت » در نشریات گروه « زراعت »

Increasing fruit yield and improving fruit size along with high dry matter percentage, is the main goal of kiwifruit growers in the worldwide. There are deferent techniques to access exportable fruit size with high dry matter content in kiwifruit including summer pruning, root pruning and flower and fruit thinning. Furthermore, trunk girdling and plant growth regulators such as Forchlorfenuron (CPPU) are widely used in modern kiwifruits orchards to increase fruit yield and quality.

In this study, the effect of vine trunk girdling at different times (spring, summer, autumn), CPPU (10 mg L-1 of active ingredients in water), combined effect of CPPU and summer girdling as compared to control (without girdling and CPPU treatments) on fruits quality of Hayward kiwifruit at harvest and the end of cold storage was evaluated in complete randomized block design in 1398. Fruits were harvested based on soluble solids index and fruit quality was measured immediately after harvest and after three months storage at 1o°C.

The results showed that the summer girdling with CPPU, CPPU alone and spring girdling increased 37.99, 32.19 and 22.11% of kiwifruit weight compared to control respectively. Application CPPU increased fruits weight, length and diameter, but decreased fruits dry matter percentage and the ratio of soluble solids content to titratable acidity (SSC/TA) the compared to control. No significant differences were found between CPPU treated fruits and control for fruit tissue firmness, soluble solids content at harvest time and after three months storage in cold storage. The summer trunk girdling together with CPPU spray increased fruit weight (38% as compared to control). In addition, this treatment showed the highest fruit dry matter percentage, soluble solids and SSC/TA at harvest time and the lowest fruit weight loss (0.66%) with the highest fruits tissue firmness (3.96 kg force) at the end of three months storage time. Summer girdling showed the highest fruit weight loss (2.54%) at the end of storage, while no significant difference was found between autumn and spring girdling treatments compared to the control.

Overall, the results showed that summer vine trunk girdling with CPPU spray not only improved kiwifruit size and yield but also improved fruit quality by increasing fruits dry matter percentage and soluble solids content. Such fruits showed the longer postharvest life as compared to control and other treatments. Therefore, it is recommended for improving fruit size and quality in Hayward kiwifruit, CPPU spray was applied with summer vine trunk girdling.

In the present study, seven native and five introduced pear (Pyrus communis L.) cultivars were evaluated for fruit morphological traits and biochemical characteristics including total soluble solids, total titratable organic acids, acidity of juice, sclereid cell density and size, ascorbic acid and organoleptic attributes. The results showed that in fruit morphological evaluations, the most important distinguishing traits were general shape and fruit size, length: diameter ratio, position of maximum diameter, fruit side profile, background color and size of lentils in ground color, size of over color area and the characteristics of fruit stalk. Also, three very similar cultivars, Coscia, Louis Bonne and Spadona, showed that these similarities has caused synonym and homonym names for them in some nurseries. However, they were distinguishable by the fruit characteristics including size, thickness and curvature of stalks. Total soluble solids contents of fruit varied from 14 to 17.4%, and the lowest was observed in Beurre Giffard cultivar and the highest in Felestini. Total titratable acid content of the fruit also varied between 3.4 mg g-1 of fresh weight in cv. Dargazi, cv. Louis Bonne and cv. Spadona and 11.4 mg g-1 of fresh weight in cv. Domkaj. In general, the highest overall score of fruit quality in organoleptic evaluations belonged to cv. Louis Bonne, which due to its excellent quality at the ripening time and other characteristics such as compatibility with the clonal rootstocks and fire blight tolerance has become the most popular commercial pear cultivar in Iran, in recent years.

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.

Recently, Fuji apple has been considered in Iran, however its production comes with problems such as decay and internal browning incidence during long-term storage. In this study, one minute postharvest dipping of two organic calcium compounds including Calcicat and Folical was compared with calcium chloride on Fuji apple in and the friut quality was investigated. According to the results, after three and six months storage, the fruits treated with tree types of calcium solutions had higher calcium content than the control. Acidity content and tissue firmness of fruits reduced during storage, but this reduction in fruits treated with CaCl2 and Folical was lower than the control and fruits treated with Calcicat. The immersed fruits in different calcium solutions produced lower ethylene. Flesh phenolics and antioxidant activity of samples were affected by calcium treatments significantly. The highest phenolics and antioxidant activity were found in fruits treated with CaCl2. Significant variation was observed among fruits treated with different calcium compounds regarding storage disorders incidence, so that fruits treated with Folical showed lower decay and internal browning.

In order to preserving of button mushroom during storage, an experiment was carried out through a factorial experiment based on a completely randomized design. In this research the effect of calcium ascorbate (0, 0.4 and 0.8 percent) and hot water treatment (45°C) was investigated on qualitative characteristics such as weight loss, firmness, vitamin C, total phenol, polyphenol oxidase activity (PPO) and color parameters. After treatment, mushrooms were kept at 1 ± 0.5°C and 90% relative humidity and then qualitative characteristics were evaluated after 0, 10, 15, 20 and 25 days. The results showed that calcium ascorbate associated with heat treatment had significant effects on weight loss, firmness, color parameters and PPO activity. The effect of time on all parameters in statistical level 1% and the interaction effect of treatment and time on weight loss, color parameters and PPO activity were significant. The best results in preserving mushroom quality appeared to be obtained from 0.8% calcium ascorbate with heat treatment.

Bell pepper (Capsicum annuum L.), due to its high nutritional values, is one of the most important vegetable crops in the world. Optimum supply of nutrients particularly potassium, has important role in improving the quality of agricultural products. This research was conducted to study the effects of potassium levels (150, 235, 300, 400 and 500 mgL-1in nutrient solution) on fruit quality of bell pepper. The results showed that the effect of K levels on fruit length, fruit firmness, and biochemical traits was significant (P≤0.05), while there was no significant effects of potassium levels on fruit diameter. The highest fruit length and fruit firmness were observed in plants treated with 400 and 500 mg K L-1 nutrient solution, respectively. The highest amount of TSS and pH of fruit juice were recorded in 400 mg K L-1 treatment, whereas the highest titreable acidity and vitamin C were in plants treated with 500 mg K L-1 nutrient solution. Therefore, it can be concluded that for improvent of fruit quality of Bell pepper in hydroponic system, higher potassium concentrations (400 mgL-1) rather than normal concentrations (around 235 mgL-1) should be applied.

In order to investigate the effects of pre-harvest salicylic acid (SA) treatments on fruit quality and antioxidant activity of two apricot cultivers (Shakarpareh and Shamlou), an experiment was conducted, based on complete randomized blocks design. Apricot trees were treated with four concentrations of salicylic acid (0, 1.5, 3 and 4.5 mM) 6 days before harvesting. Fruit were harvested on physiological ripening in both cultivars and some characteristics such as fruit firmness, total soluble solid (TSS) contents, titratable acidity (TA), ascorbic acid content, total phenolic contents and total anti-oxidant activity were determined in treated and non-treated fruit. Results showed that pH and TSS were decreased in chemical-treated fruit but TA, fruit firmness, total flavonoids and total phenol were increased significantly in both cultivars. Salicylic acid treatments had no significant effect on ascorbic acid content and antioxidant activity. The highest value of fruit firmness, TA, total phenol content in Shakarpareh were observed using 4.5 mM SA but the lowest value were found in non-treated fruit. The highest flavonoid contents in this cultivar were recorded in the 3 mM SA. In Shamlou cultivar, the highest value of fruit firmness, TA and total flavonoids were observed in 3 mM SA.

The aim of this study was to determine the effects of hot water dips on chilling injury of karaj persimmons. Fruits were subjected to hot water dips at 20, 45, 50 or 55°C for 10 or 20 min. Treated and untreated fruits were then kept at 1°C and 85 - 90% relative humidity for 4 months. Fruit weight loss, firmness, total soluble solids (TSS), titratable acidity (TA), total phenolic content (TPC), soluble tannin content, chilling injury, antioxidant activity, electrolyte leakage (EL) and Malondialdehyde (MDA) content were measured 0, 15, 30, 45, 60, 75, 90, 105 and 120 days after storage. Peroxidase (POD) and catalase (CAT) activities were also determined at the end of storage. Hot water treatments had significant effects on firmness, TSS, TPC, soluble tannin content, chilling injury, EL and MDA content. Although the best results obtained in fruits that treated by 55°C for 20 min but this treatment had unpleasant effect on appearance and taste of fruits. So 50°C for 10 or 20 min and 55°C for 10 min were recognized the best treatment for maintaining fruit quality and reduce chilling injuries in Karaj persimmons.

In this research, peach fruits cv. Kousari, were treated at different temperatures of CaCl2 concentrations for 5 minutes as a dipping method. After treatment, fruits were stored at 2-3˚C with a relative humidity of 80-90% for 28 days and then, the role of temperature and calcium chloride on qualitative characteristics and shelf life were evaluated every week. The experiment was carried out with five treatments of temperature(4, 8, 16, 32, 64°C) for five minutes and two levels of calcium chloride (0 and 60 mM) as a factorial experiment based on complete randomized design with three replications. The results showed that the temperature of 64°C with calcium chloride was found to be the best treatment to maintain fruit qualitative parameters such as fruit firmness, vitamin C content, total soluble solids, fresh weight loss and calcium content. High temperature treatment without CaCl2 was also effective in maintaining of fruit firmness and reducing fresh weight loss.

To determine the effects of pre-harvest salicylic acid (SA) treatments on postharvest life and quality of apricot fruits، four different concentrations (one، 1. 5، three and 4. 5 mM) were applied six days before harvesting of apricot fruits cv. ‘Shamlou’. Fruits harvested at commercial maturity stage and stored at 2ºC with 90 percent RH on the same day for a period of three weeks. The fruit was evaluated for weight loss، flesh firmness، total soluble solid (TSS) contents، titratable acidity (TA)، ascorbic acid contents، total phenolic contents and total flavonoids in treated and nontreated fruits. Results showed that salicylic acid treatments significantly exhibited weight loss and flesh firmness compared with control. At the end of storage، the highest ascorbic acid content and total phenolic content was observed in 4. 5 mM SA treated fruits. The highest flesh firmness، titratable acidity and flavonoids were observed at three mM SA treated fruits and at the end stage of storage. The lowest weight loss، TSS and pH were recorded at 3mM SA treated fruits.

In this study, the effect of foliar spray with calcium chloride (0, 0.75, 1.5 and 3 g L-1) during 2, 4 and 6 weeks before commercial harvesting time of apple fruit cv. ‘Gala’ and ‘Delbarestival’ which trained in three different systems (V shape, HighTech and Cordon) was investigated. The results showed that types of training systems and foliar application of calcium can affect on fruits quality at harvest time. Tree yield, fruits weigh and fruit tissue firmness of ‘Gala’ was significantly higher than ‘Delbarestival’. Furthermore, calcium spray increased fruit firmness in compared to control and TA deacresead in compared to control. Calcium treatment increased fruit skin a* value that means more antocyanin synthesis and redness. Results generally showed that ‘Gala’ apple trained in HighTech and V shape systems as well as ‘Delbarestival’ in HighTech produced the higher fruits weight and size as well as quality favorite in compare to other system.

Calcium and boron as plant nutritional elements play major roles in plant physiological processes including regulating various cell and plant functions. Considering the importance of both elements, this study was conducted during 2010-2011 in the Experimental Asian Pear Orchard at Faculty of Agriculture, Tarbiat Modares University. Different concentrations of calcium chloride (0, 0.5 and 0.7 percent) and acid boric (0 and 0.5 percent) were used as foliar spray of Asian pear cultivar "KS10" during growing season. The results showed that foliar application of calcium and boron led to the improvement in physicochemical characteristics of pear fruits. Under treatment conditions, fruit tissue hardness increased, while total soluble solids decreased. Various concentrations of calcium resulted in decreasing fruit softening, although after 3-month's storage all treatments showed low fruit firmness. Total phenolic compounds decreased more significantly in control fruits compared to in fruits sprayed with calcium and/or boron during the storage. The highest and lowest levels of polyphenol oxidase activity were found in elements-sprayed fruits and non-sprayed ones respectively. In brief, calcium and boron application resulted in improving postharvest characteristics of Asian pear fruits and reducing internal browning symptoms.

The main factor affecting fruit quality and post-harvest loss in kiwifruits is improper tree nutrition. In this study, fruits were harvested from 24 different orchards in the east of Guilan province when the total soluble solid content of the fruit was 6.2°. percent the fruts was. Fruits’ mineral content such as nitrogen, phosphorus, potassium, calcium and magnesium, the mineral elements ratios and also fruits firmness were measured after harvest. Thereafter, fruits were transferred to cold storage at 0 ºC temperature and 90% relative humidity and after 15 weeks, fruit tissue firmness, water loss, ethylene content and respiration severity were measured. There was a significant positive correlation between fruits tissue firmness with fruit calcium content, but a significant negative correlation with potassium and nitrogen content, N:Ca, N+K:Ca. K:Ca and K+Mg:Ca ratios. At the end of storage, there was a significant positive correlation between fruit tissue firmness with calcium content at harvest time and a significant negative correlation with nitrogen, phosphor us and potassium content and N:Ca, N+K:Ca, K:Ca and K+Mg:Ca ratios. Furthermore, fruits’ weight loss showed a significant positive correlation with potassium content. There was a significant negative correlation between ethylene level and fruit tissue firmness at the end of storage and a positive correlation with N:Ca and N+K:Ca ratios. Cluster analysis divided kiwifruit orchards into two main groups. In conclusion, the results showed that the kiwifruit mineral elements’ content and ratio at harvest time can be used as an effective factor for evaluating post-harvest life of kiwifruits.

Penicillium expansum Link. is a major decay agent of fruits including peach and nectarine، in storage. In this research، relative resistance of fourteen commercial and local peach and nectarine cultivars to blue mold in cold storage and its correlation with physicochemical traits as potential resistance indicators were studied. For inoculation، the fungus conidial suspension was prepared and inoculated in wells in equatorial region of fruit. The fruits were then transferred to a cold storage room and lesions diameter was measured six weeks later. Pomological traits including cortex firmness، epidermal toughness، total soluble solids، titratable acidity and total acidity were also measured and their correlation with lesion diameter was studied. Based on the results، different susceptibility levels were observed in cultivars and mean lesion diameter varied from 3. 31 cm in Shams cultivar to 0. 58 cm in Sunglu cultivar. Clustering based on lesion diameter indicated that Shams was highly susceptible، Anjiri، MHF101، Independence، Rome Star، MHF100، MHF102، Nectared 9 and Nectared 4 were susceptible and GH Hall، Red Skin، Sunglu and Nectared 6 were relatively resistant. All cultivars varied in physicochemical traits. A negative correlation was observed between lesion diameter and titratable acidity and epidermal toughness but these relations were not strong enough to be used as decay resistance criteria.

Grape is non-climacteric fruit and as a result, the quality of fruit does not change after harvest. Application of ethephon in recent years is known as an effective way to increase the quantity and quality of grape. In this study, the effect of pre harvest application of ethephon at four levels (0, 150, 250 and 300 mg/l) and ethephon treatment time at two levels (10-20% and 50-70% of berry veraison) were evaluated on quality indices of Bidane -Ghermez grape cultivar at harvest time. The experiment was carried out with a factorial design in a randomized complete block with three replications. Evaluated indices were soluble solids content, titratable acidity, palatability, pH, ascorbic acid content, tissue firmness and fruit color. Application of ethephon increased soluble solids content, ascorbic acid content, palatability and fruit color but had no effect on pH. Colorimetric results showed that ethephon treatment reduced L parameter, Hue angle and Chroma and increased a/b ratio. Titratable acidity and tissue firmness were decreased with application of ethephon. Results showed that spray of 150mg/l ethephon at 50-70% of berry veraison increased soluble solids content, palatability and fruit color but had no more effect on reducing tissue firmness. Based on the obtained results, application of ethephon with the optimum concentration in the proper time can be an effective strategy to improve color and optimum quality of berries.

Citrus fruit quality preserve the post harvest cause marketability increased. In this research, the effect of putrescin and gibberellic acid concentrations on storage life of sweet orange fruit (Hamlen cultivar) was studied to in factorial design (3*3*6=54)based on randomized complete block with six replications. Putrescin at three concentrations(0, 1 and 2 mM) and three level of gibberellic acid (0, 50 and 100 mg/L) were sprayed on the tree at the physiological maturation stage and two weeks pre harvest. Fruit firmness, marketability, vitamin C, total acidity, total soluble solids (TSS) and ratio of total soluble solids (TSS) to total acidity were evaluated. The results showed that putrescin spraying at 1 mM significantly prevented fruit softening and preserved fruit firmness. Also putrescin treatment (1 mM) preserved ideal marketability and was superior than other treatments. Gibberellic acid significantly preserved total acidity and total soluble solids. The interaction of gibberellic acid and putrescine also preserved significantly vitamin C. Therefore, the application of putrescine at 1 mM and gibberellic at 100 mg/L was recommended for preserve marketability, appearance and quality of citrus sinensis cv. Hamlen.

In order to recognize and select Iranian onion cultivars with the best quantitative and qualitative characters such as yield, neck thickness, size, form, number of scales, storability, dry matter, total soluble solide, firmness and determine the relation of some characters on storability, this experiment was conducted at Karaj in 1999-2000. Field experiment was carried out based on Randomize Complete Block Design with four replications and five treatments Ghermez Azarshahr, Sefide Kashan, Sefide Qhom, Tarom Zanjan and Dorche Isfehan onion cultivars. For determination of the storage ability of Onion cultivars, a study was carried out in a factorial experiment based on completely randomized design with three replications in common storage conditions. Factors were cultivars with five levels and dates with eight levels. In a period of four months at 15 days interval, (8 distinct dates) losses were measured according to percentage of weight loss, sprouting and rotting. The rate of changes of some traits such as total soluble solids (T.S.S), dry matter (Dm), bulb firmness were also determined during storage. Results showed that in field experiment, the highest and lowest yields were obtained from Sefide Qum cultivar (60.82 tha-1) and Dorche Isfehan (32.03 tha-1) respectively. Sefide Qum cultivar had the lowest percentages of weight loss, sprouting and rotting during storage (15.33% and 11.72% respectively), which were not significantly different from those of Germez Azarshahr and Dorche Isfehan. Tarom zanjan cultivar had the highest weight loss, and Sefid Kashan had the highest bulb sprouting and rotting during storage period (23.06% and 55.46%, respectively). In storage period, some qualitative characters such as dry matter and total soluble solids increased slightly, but bulb firmness decreased. Sefid Qum cultivar had the highest total soluble solids, dry matter and bulb firmness (9.81%, 11.8%, 39.19 N, respectively), and Tarom Zanjan the lowest (8.37%, 9.29%, 34.3 N, respectively). A highly significant positive correlation (r =0.84) and linear regression equation (y = -2.472 + 1.424x) was found between total soluble solids and dry matter of bulbs. During storage, a significant negative correlation of (r = -0.592) and linear regression equation (y=101.515-1.863x) was found between bulb firmness and sprouting and rotting.