مجله علوم و فنون باغبانی ایران
سال بیستم شماره 4 (زمستان 1398)

Pistacia vera ‘Badami-Riz-Zarand’ is used as rootstock in Iranian pistachio orchards due to the low sensitivity to the Phytophthora, resistance to salinity, and graft compatibility with commercial cultivars. In this study, the effects of culture media (MS and DKW) along with type and concentration of plant growth regulators were investigated on micropropagation of this rootstock. The highest growth of explants was obtained in ½ DKW culture media. Supplementing the culture media with antioxidants and activated charcoal has no significant effect on explants establishment. Most of the microshoots (5 to 6 microshoot in each explant) were induced on DKW+1 mg L-1 BA, DKW+2 mg L-1 BA + 0.5 mg L-1 GA, and also on ½  DKW culture media supplemented with 0.5 mg l-1 BA or combination of 1 or 2 mg L-1 BA + 0.5 mg L-1 GA, whereas, the length of the microshoots were higher in MS medium (3.84 to 5 cm). At rooting stage, half strength MS media supplemented with 2 mg L-1 IBA and 0.05 mg L-1 NAA showed the highest root length (4.48 cm), number of roots per microshoot (4.5), and rooting frequency (86.36%).

In this study, the effects of postharvest application of γ-aminobutyric acid (GABA), methyl jasmonate (MeJA) and methyl salicylate (MeSA) on chilling injury, peel attributes and fruit juice quality of ‘Moro’ blood orange during cold storage at 3 °C and 90% RH for 150 days was investigated. GABA treatment at concentrations of 20 and 40 mM using vacuum at 30 kPa for 8 minutes and MeJA and MeSA vapor treatments at 50 and 100 μM separately for 18 hours were used. Sampling was carried out on 1, 30, 60, 90, 120 and 150 days of storage. Treatments reduced the chilling injury and electrolyte leakage. Control fruit had the highest index of chilling injury and electrolyte leakage at the end of the storage period. The lowest peel moisture and fruit juice and the highest total soluble solids (TSS) and pH were obtained in control fruit. MeSA treatments had the lowest a* and the highest Hue° while the lowest lightness (L*), b*, Hue° and chroma were obtained in control fruit. Overall, 100 μM MeSA was the most effective treatment for reducing chilling injury and maintaining the peel and fruit juice attributes of ‘Moro’ blood orange during cold storage.

Commercial production of uniform and healthy seedlings to be used as a rootstock in a controlled environment has become commonplace. Any attempts to enhance their growth and shorten the preparing period for grafting will be of value and reduce the cost of production.  The aim of this study was to investigate the interaction of growth regulators including gibberellic acid (GA3) with a concentration of 0 and 100 mg L-1 and subsequently paclobutrazol (PBZ) with a concentration of 0 and 500 mg L-1 and nutrient sources of urea 0 and 0.5% and nickel sulfate 0 and 150 mg L-1 on seedling growth of volkameriana. Results indicated that 100 mg L-1 GA3 accompanied by 0.5% urea and 150 mg L-1 nickel sulfate significantly increased stem length and treatment combined with PBZ 500 mg L-1 gave the highest rate of stem diameter.

Different concentration of salicylic acid foliar spraying on antioxidant system and postharvest quality attributes of kiwifruit were investigated. For this purpose, Hayward cultivar was used and SA treatment, at 0 (control), 0.5, 1 and 1.5 mM, were applied at two times of final steps of during [A1] fruit development (125 and 145 days after flowering). Fruits were harvested at commercial maturity (TSS=6.2 Brix) and stored at 1.5±1°C and 90±5% relative humidity for 14 weeks. Different characteristics of the fruit were evaluated at 0 (before storage), 11 and 14 weeks after harvesting. The results show that, the highest firmness of fruit tissue was related to 1.5 mM SA and its lowest was related to the control. In addition, kiwifruit treated with SA has higher significantly total chlorophyll content, L*, and b* values and lower a* value, pH and total soluble solids (TSS) than the control. Preharvest SA treatment reduced the microbial activity (log CFU g-1) of kiwifruit during storage. Also, the higher amount of total phenol, ascorbic acid was related to 0.5 mmol SA and the higher amount of antioxidant capacity was related to 1 mmol SA, in which SA improved the antioxidant compounds of kiwifruit. Ultimately, it seems that preharvest treatments with SA could be a promising strategy to maintain postharvest quality and improve the health benefits of kiwifruits consumption by increasing the antioxidant capacity.

In order to investigate the heterosis and genetic relationships of different tomato lines for some qualitative characteristics, five diverse tomato lines were evaluated in a complete diallel cross design. Analysis of variance showed significant differences (P<0.01) among the genotypes for total soluble solids, total acidity, maturity index, antioxidant capacity, ascorbic acid, total flavonoids, and total phenols. The highest heterobeltiosis was observed for total phenol and total flavonoid. Results of Hayman's analysis showed that contributions of additive and non-additive effects were involved in the control of the studied traits. The genetic analysis by Hayman method showed that the attributes except the total phenol, were under the control of the dominance type of the gene action, and their low inheritance indicated the more involvement of non-additive type of gene action. Therefore, due to low heritability and lack of high selection potential, hybridization methods and heterosis phenomenon could be used in the first generation to improve these traits. In contrast, the high specific heritability of total phenol indicated that this trait is controlled by the additive gene effect. Therefore, due to the high selection potential for total phenol, it is possible to modify the population by selection the best genotypes for this trait. Overall, hybridization methods can be used to improve fruit quality traits in tomatoes.

Rainfed figs are damaged by birds, red bees and heat stress. Although the application of net covering on the trees is a suitable method for reducing this kind of damage, net effects on vegetative and reproductive characteristics of fig has not yet been determined.  The aim of this experiment was to determine the effects of net color and shading on some characteristics of fig tree under rainfed conditions. For this purpose, a research was carried out on rainfed fig (Ficus carica L. cv. Sabz) in a randomized complete block design as factorial experiment with net color (black, white, blue, green and red) and shading (30 and 50%) factors plus control (without net) at Estahban fig research station in 2017-2018 . Results showed that the blue net was the best color because of the least disorders (chlorosis and necrosis), the largest leaf dimensions (length and width) and chlorophyll a concentration and suitable influence on the quantity and quality of the fruit. The blue net with 30% shading increased the dimension, relative water content and stomatal conductance and reduced defects  and ion leakage of leaf. The control trees had the highest level of disorder  sign and was under drought stress, but some of the nets, especially blue net with 30% shading showed a favorable effect on fig characteristics and reduced drought stress.

Keeping anthurium cut flowers under 15o</sup>C leads to chilling damage and reduction in flower vase life. In this research, the effects of postharvest GABA treatments (0 and 1,5 mM) on vase life, membrane stability, spathe browning, antioxidant enzymes activity (CAT, SOD), and MDA content during 10 days' storage at 5 and 10 o</sup>C were studied. The results revealed that the longest vase life was observed in 1 mM GABA and 10 o</sup>C. Untreated flowers showed the least membrane stability and the highest MDA content in chilling temperatures. SOD activity was increased using 5 mM GABA . The flowers treated with 1 mM GABA had more CAT activity. GABA treatment had no effect on spathe browning. Finally, it can be concluded that both concentrations of GABA (1 and 5 mM) were effective to induce chilling resistance in anthurium cut flowers. </div

In this experiment one determinate line and one indeterminate F1 hybrid tomato (Moneymaker × San Marzano) were grafted on two potato cultivars (Agria and Satina) as root stock. Experiment was conducted as factorial based on CRD design with four replications. Some traits related to growth, physiology, yield and fruit quality of tomato including the foliage fresh and dry weight, plant height, chlorophyll index, fruit weight, total soluble solids and titratable acidity were assessed. The highest fruit yield (0.29 kg per plant) was obtained in graft combination of indeterminate tomato on Agria rootstocks this treatment also showed the best growth parameters and fruit quality. When indeterminate growth tomato was grafted on potato rootstocks, none of them (cv. Agria and Satina) produced tubers, while when these potatoes were grafted by determinate growth tomato both of them produced tubers as well as tomato fruits. Results indicated the existence of scion-rootstock interaction at least for potato tuberization and it seems producing two satisfactory crops from one grafted plant need more search for finding suitable tomato scion and potato rootstocks.

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