Pomology
S.M Gholami; M. Hadadinejad; H. Moradi; H. Sadeghi
Abstract
Introduction
Bud dormancy is one of the important issues in planting and cultivation of fruit trees that needs to be addressed in many trees such as orange (Citrus sinensis). Bud dormancy involves cessation of horizontal and vertical growth, lack of budbreak, and reduction in plant activity during cold ...
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Introduction
Bud dormancy is one of the important issues in planting and cultivation of fruit trees that needs to be addressed in many trees such as orange (Citrus sinensis). Bud dormancy involves cessation of horizontal and vertical growth, lack of budbreak, and reduction in plant activity during cold weather. One of the commercial orange cultivars is Tarocco blood orange which compared to older blood cultivars, is larger in size and with lower alternate bearing has higher marketability. The nursery trees of this cultivar are grafted on sour orange, citrange, and vigorous rootstock of citrumelo (a hybrid between trifoliate orange and grapefruit) (Talon et al., 2020). One of the major problems of nurserymen in spring grafting of Tarocco cultivar on vigorous citrumelo rootstock is the failure of about 50 percent of buds to break compared to other cultivars on the same rootstock and other similar rootstocks. This unwanted dormancy leads to a one-year delay in the nursery tree production process and unnecessary occupation of nursery space. Given the commercial importance of blood orange and the adverse effects of bud dormancy on yield and fruit lifetime, solutions are used to control and overcome this problem. One of the effective solutions is the application of cytokinins which can stimulate the growth of graft buds (Yadav & Saini, 2018).
Materials and Methods
This research was conducted in a citrus nursery at the University of Agricultural Sciences and Natural Resources of Sari, in late May 2022. Citrumelo seedlings were grown in 5.3 liter pots containing a loamy-silt soil mix in the nursery location. Tarocco cultivar buds were prepared from a seven-year-old mother orchard and T-budding was performed in June (during rootstock bark slipping). All hormone treatments were applied after graft union and before bending the branch using a soft brush on the graft buds. The applied treatments included hormone treatment (control, 5000 mg.l-1 benzyladenine, 1000 mg.l-1 kinetin, and 50 mg.l-1 thidiazuron) and treatment time (13, 15, and 17 days after grafting). After two months, some traits related to budbreak and growth of the grafted buds were evaluated.
Results and Discussion
The results showed that thidiazuron and benzyladenine treatments had better effects compared to kinetin treatment on spring budbreak and initial growth of Tarocco grafted buds. In a way that 50 mg.l-1 thidiazuron treatment had the highest number of sprouted buds (67.91), largest leaf area (118.04 cm2), highest number of leaves (16.50), especially when applied 13 days after grafting. Also, in leaf size related traits, leaf area indices, graft growth rate as well as chlorophyll and carotenoid content of Tarocco graft leaves were significantly affected by different hormonal treatments and application times, with 50 mg.L-1 thidiazuron being more effective than other treatments. Cytokinins can promote division and expansion of leaf cells and thereby result in increased cell numbers and improvement of different leaf parameters. Also, cytokinins regulate important physiological processes like photosynthesis. Application of these materials provides cell division especially in areas like buds and growth points and also possibly more buds may form on the spring graft by using these treatments during the grafting process which can lead to increased bud break and faster plant growth (Cook & Bahar, 2017). Increasing cytokinin levels can stimulate the photosynthesis process which results in increased food production, leaf growth and ultimately increased leaf area. On the other hand, cytokinins affect plant metabolism and can regulate production and accumulation of different growth factors. This may lead to a better balance in nutrient distribution and metabolic activities which in turn aids leaf area increase (Hodchek et al., 2023). Finally, according to the obtained results, it can be recommended to nurserymen of this cultivar to use 50 mg.L-1 thidiazuron 13 days after grafting as a practical and effective strategy for increasing spring budbreak, growth and development of Tarocco buds grafted on citrumelo.
Conclusions
In general, based on the results, the application of 50 mg.l-1 of thidiazuron 13 days after grafting can be considered a practical and effective strategy to enhance bud awakening, as well as the growth and development of Tarocco spring shoots on citronmelo. This practice is recommended for producers of seedlings of this cultivar.
Sepideh Taghizadeh; Hossein Sadeghi; Mehdi Hadadinejad
Abstract
Introduction: Influx of Siberian cold air masses into the northern parts of Iran causes severe decrease in temperature, heavy snowfall and freezing of citrus every few years. Depending on the temperature drop, in some years only fruits and in some years, citrus trees suffer severe damage too. One of ...
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Introduction: Influx of Siberian cold air masses into the northern parts of Iran causes severe decrease in temperature, heavy snowfall and freezing of citrus every few years. Depending on the temperature drop, in some years only fruits and in some years, citrus trees suffer severe damage too. One of the sudden drops in temperature was in January 2007, when the temperature dropped from -7 degrees Celsius to -13 degrees Celsius. Consecutive damage to citrus trees and crops in the north of the country has caused citrus gardeners to despair of its economic viability and to refrain from rehabilitating destroyed orchards. The mechanisms of frost resistance and relative tolerance to cold in citrus include physiological adaptation and metabolic changes. These changes will lead to the production of various cellular osmolytes, the accumulation of soluble substances, changes in lipid metabolism (with an increase in unsaturated fatty acids), an increase in supercooling temperature, and ultimately an increase in plant resistance. The use of passive and active methods can also partially prevent frost damage or reduce the severity of the injury, but spraying with compounds that may provide physical protection of trees against freezing or spraying chemicals that reduce the freezing point of the cellular fluid by altering the concentration of the cell sap could be more promising.
Materials and Methods: Experimental factors include freezing temperatures at three levels (-5, -8 and -11° C) and spraying with two types of experimental material including carnauba wax in two concentrations of zero and four percent (manufactured by Orange Saft SL, Spain) and glycol potash in two concentrations of zero and 10% (prepared by Pooshesh sabze Company, Iran), carnauba + glycol potash (carnauba wax in 4% concentration and 10% glycol potash concentrate) and control (distilled water solution).
Results: Electrolyte leakage is the uncontrolled leakage of organic ions from the cell membrane due to stress and damage to the membrane. The lowest electrolyte leakage was observed at -5° C and the highest one was at -8° C. As a messenger molecule, proline is effective in regulating mitochondrial activity, cell proliferation, and cell death. Proline also expresses certain genes that are essential for improving plant conditions under stress. Proline concentration increased with decreasing temperature but it decreased again at -8 ° C. Using carnauba wax at -5 ° C has reduced the concentration of total soluble sugars (66.92 micro g / g by weight) but did not significantly differ from the control treatment (83/23) and -11 ° C. Frost tolerance and frost resistance vary in different organs of citrus trees. Young shoots and twigs are very sensitive to cold and frost, so their tissues change color due to the cold. If the intensity of cold and frost increases, it will cause the shoots to dry out. freezing temperature has a significant effect on Shoot dying back, so that the highest dryness of the shoots was observed at -11 ° C (91.66%) and the lowest at -5° C (10.41%). The highest percentage of leaf abscission was observed at -11 and the lowest with significant difference at -5° C. Symptoms of freezing such as leaf abscission and tree Shoot dying back are not seen up to -5 ° C but they are well visible at -8 ° C. Experimental treatments also failed to prevent shoots from drying out at -11° C.
Conclusion: Thomson navel orange young trees do not suffer much damage up to -5° C, but as the temperature decreases, the damage caused by frost increases in the form of leaf abscission and Shoot dying back of branches. Carnauba wax has a positive role in this experiment by preventing leaf abscission at -8 ° C, but glycol potash has a negative role by increasing leaf abscission and Shoot dying back. Increasing leaf potassium levels through potash glycol not only did not increase cold resistance but also increased susceptibility to frost. Potassium must be supplied from other sources. The results of this experiment showed that the use of carnauba wax up to 48 hours before the possible cold, which is announced through meteorology, with a concentration of 4%, can keep it alive up to -8 ° C, which normally destroys the plant, but with passing through this temperature, for example at -11 degrees Celsius, is not able to maintain the plant.
Ara Alinejad Elahshah; Hossein Moradi; Hossein Sadeghi
Abstract
Introduction: Strawberry (Fragaria × ananassaDuch.,Rosaceae). fruitis rich of fiber, vitamin C, potassium and antioxidants. Since the balance of nutrients at the appropriate time for commercial fruit production, yield improvement and fruit quality is essential, so foliar application at key stages could ...
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Introduction: Strawberry (Fragaria × ananassaDuch.,Rosaceae). fruitis rich of fiber, vitamin C, potassium and antioxidants. Since the balance of nutrients at the appropriate time for commercial fruit production, yield improvement and fruit quality is essential, so foliar application at key stages could have a positive effect on the quantitative and qualitative characteristics of perennial crop fruits. Among essential mineral nutrients that are involved on plant physiology, micronutrients of zinc (Zn) and boron (B) because of their association with synthetic hormones are particularly important. In a study by Lolaei et al. (2012) conducted showed that the foliar application at flowering stage increased fruit quality and yield of strawberrycultivar ʻCamarosa’. The results of Rafeii and Pakkish(2014) indicated that spraying of strawberry cultivar ʻCamarosa’ with boric acid had a significant effect on yield, fruit weight, chlorophyll and leaf area. So according to the importance of micronutrients on horticultural yield improving and environmental protection, this investigation was conducted to evaluate the effect of foliar application of zinc and boron and combination of them on quantitative and qualitative characteristics of strawberry cultivar ʻAromas’ in hydroponic system.
Material and Methods: The experiment was arranged in factorial based on a complete randomized block design with 9 treatments and 9 replications in 2015 and 2016 in greenhouse and laboratory of Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT), Sari Agricultural Sciences and Natural Resources University, Sari, Iran. Experimental treatments were included: zinc at three levels (0, 100 and 200 mg l-1) of fertilizer source zinc sulfate and boron at three levels (0, 500 and 1000 mg l-1) of fertilizer source boric acid as alone or combined. Spraying of strawberry cultivar ʻAromas’ at 3 stages in hydroponic system were applied after the chilling requirement treatment. When Fruits were stained 75-80% and have appropriate size, were harvested. Traits that were evaluated include: vitamin C, antioxidant activity, total soluble solids (TSS), titratable acidity (TA), taste index (TSS/TA), pH of fruit juice, chlorophyll a, chlorophyll b, carotenoid, fruit weight, fruit length and diameter, leaf number, petiole length and plant height. The data collected were statistically analyzed using the computer software using SAS 9.1 and MSTATC, Analysis of variance techniques were employed to test the overall significance of the data, while the least significant difference (LSD) test (P ≤ 0.05) was used to compare the treatment means.
Results and Discussion: Results indicated that foliar application of Zn and B significantly affected on the vitamin C, antioxidant activity, TSS, TA, TSS/TA, pH of fruit juice, chlorophyll a, chlorophyll b, carotenoid, fruit weight, fruit length and diameter, leaf number and plant height (1% or 5% of probably level), while the Petiole length was not significantly affected. Between the different nutrient levels of zinc sulfate application at the concentrations of 100 and 200 mg l-1, boric acid application at the concentration of 500 mg l-1, the combination of zinc sulfate at 100 and 200 mg l-1 with boric acid at 500 mg l-1 play a significant role at increasing studying characteristicsexcept the content of TA. Zinc is effective at the formation of growth hormones and chloroplasts, it is also necessary for chlorophyll biosynthesis and also plays a very important role at cell division and the protein synthesis and carbohydrates metabolism. It seems this subject caused increased plant height, leaf number, petiole length, diameter, length and weight of the fruit and chlorophyll by foliar application. Boron is an element which increases weight by effect of reproductive growth and help to material production, production and transfer of carbohydrate, and nutrient by boron is necessary for fruit set and fruit retention. The results showed that zinc sulfate is effective on TSS, TA, taste index and pH, the increase may be attributed to their effects on different enzymes which are involved in the formation of proteins, acids and sugars, also enough amounts of boron in the plant, increased carbohydrate transport to fruit and areas of active growth and its effect is evident in increasing the amount of fruit sugar. Because of increased vitamin C and antioxidant capacity of plants had been sprayed with boron and zinc can be attributed to zinc that plays an active role in auxin production in plants, and vitamin C increases the production of auxin. Similarly, Kazemi (2014) reported the highest pH of fruit juice, TSS and TA at 150 mg l-1 of Zn for strawberry cultivar ʻPajaro’ and the lowest of these parameters was recorded in control. The results of our study is in accordance with Mashayekhi and Atashi(2012) who reported a significant positive correlation between chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid content of strawberry cultivar ʻCamarosa’ leaves that had been sprayed by B and sucrose. As Khan et al. (2015) simultaneously combined application of Zn and B in the ʻKinnow’ mandarin fruit increased vitamin C, tree height and fruit weight, diameter and length significantly that was consistent with our results.
Conclusions: Since the foliar application of zinc sulfate at 100 and 200 mg l-1 with boric acid at 500 mg l-1 showed significant effect on quantitative and qualitative properties of strawberry, so to reduce the environmental effects caused by the indiscriminate use of chemical fertilizers, foliar application of micronutrients is recommended as an effective management solution in the production of strawberry cultivar ʻAromas’ under hydroponic culture.
Kambiz Mashayekhi; Hossein Sadeghi; Vahid Akbarpour; Sadegh Atashi; Yousef Ghasemi; Seyyed Javad Mousavizadeh
Abstract
Carbohydrate flow between vegetative and reproductive parts of trees is one of the determining factors of yield and fruit quality. Therefore, it varies during different times of growth season. The aim of this study was to investigate the carbohydrate content variation during growth season between leaf ...
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Carbohydrate flow between vegetative and reproductive parts of trees is one of the determining factors of yield and fruit quality. Therefore, it varies during different times of growth season. The aim of this study was to investigate the carbohydrate content variation during growth season between leaf and fruit of nectarine. So, eight nectarine trees cv. Red Gold selected randomly in the orchard and after labeling two of them combined and four replications achieved for laboratory tests. Results indicated that the highest fresh (9.3 g) and dry (3.3 g) weight of the leaves recorded at the last harvesting stage. Fresh to dry weight ratio showed a descending trend than can be indicated this fact that leaf biomass is low at primary harvesting stages and increased gradually. Chlorophyll a, b and ab reached to the highest content at the last harvesting stage. Total sugar content showed an ascending trend at second and third harvesting stages and decreased at final harvesting stage. Fruit chlorophyll content also decreased by maturation and fruit ripening; while, anthocyanin content showed an ascending trend. Fruit total sugar content decreased by third stage, two weeks after pit hardening, but increased at the final harvesting stage. Sucrose content variations show a higher value at primary stages of fruit growth in comparison with next stages and decreased by final stages. Total sugar increased at the fourth stage to third harvesting stage.
Kambiz Mashayekhi; Hossein Sadeghi; Vahid Akbarpour; Sadegh Atashi; Seyyed Javad Mousavizadeh; Malihe Abshaei; Zohre Nazari
Abstract
Citrus fruits contain numerous nutrients and secondary metabolites including sugars, vitamin C, flavonoids and phenols which have high antioxidant activity and nutritional value. Factors such as cultivar, type of stock and fruit position affect the amount of these compounds. Hence in this study the amount ...
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Citrus fruits contain numerous nutrients and secondary metabolites including sugars, vitamin C, flavonoids and phenols which have high antioxidant activity and nutritional value. Factors such as cultivar, type of stock and fruit position affect the amount of these compounds. Hence in this study the amount of sucrose, glucose, total sugar, vitamin C, flavonoids and phenols in pulp, mesocarp and flavedo of Parson Brown and Mars oranges grafted on Citrange, Cleopatra and Rough Lemon stocks were measured. According to the results, maximum of vitamin C was in Parson Brown cultivar on the Citrange and Cleopatra grafting stocks. The highest total sugar was recorded in Parson Brown and Mars cultivars on the Rough Lemon stock (P
