نشریه پژوهش های میوه کاری
سال دوم شماره 1 (بهار و تابستان 1396)

Mango is a perishable tropical fruit with a short shelf-life. Recently, using natural compounds that are safe for human and environment have gained more attention in postharvest researches. In order to evaluate the effect of different concentrations of putrescin and nitric oxide, as natural compounds, on mango fruit postharvest life, a factorial experiment was conducted based on a completely randomized design with three replications. Mango fruit were harvested from a garden in Minab city and transferred to laboratory. Fruits were immersed for 5 min in solutions of putrescine (at 0.5, 1.5, 3, 5 mM/L) and nitric oxide (at 3,9,12 µM/L), and then stored at ambient temperature for 21 days. Fruit quality attributes were evaluated at 7 days intervals. According to the results, the highest weight loss (15.5) was observed in control fruit. Fruit firmness was gradually reduced during storage, but it was slower in fruit treated with putrescine and nitric oxide. The highest tissue firmness (2.2 kg/m2) was observed in fruit treated with 3 mM/L putrescine, showing a significant difference with the control. Total soluble solids and the ratio of sugar to acidity were gradually increased during storage. The treated fruits had a lower sugar to acid ratio than the control fruit. Putrescine and nitric oxide significantly affected different color indices. The highest L* value was recorded in fruit treated with putrescine at 3 mM/L.

Use of edible coatings is one of important issues in organic fruit production and postharvest technology. This study was conducted to determine the effects of chitosan coating and salicylic acid on Botrytis cinerea extensionand quantity changes in red Rishbaba table grape. The bunches were treated with salicylic acid at 0, 1 or 2 Mm/L-1 and with chitosan at 0, 0.5 or 1% and stored at 0±0.5°c for 4 months. Fruit quality attributes including total soluble solids (TSS), titratable acidity (TA), ascorbic acid content, decay extension caused by Botrytis cinerea, bunch browning, berry browning, berry abscission and fruit taste and flavor were evaluated the end of storage period. Fruit treated with 1% chitosan × 2 Mm/L-1 salicylic acid had the highest TSS coutent and TA. 1% chitosan treatment decreased decay incidence, berry browning and berry abscission and retained maximum taste and flavor. The highest ascorbic acid content was recorded in fruit treated with 2 Mm/L-1 salicylic acid and the lowest bunch browning was observed in fruit treated with 2 Mm/L-1 salicylic acid × 1% chitosan. The results showed that 1% chitosan had the highest positive effects on maintaining quality attributes of Rishbaba table grape.

In vitro pollen germination is an effective technique for understanding the basic and applied aspects of pollen biology. In this experiment, effect of different concentrations of boric acid (0, 50,100, 200 mg l-1), calcium nitrate (0, 100, 200, 300 mg l-1), magnesium sulphate (0, 100, 200, 300 mg l-1) and potassium nitrate (0, 100, 200, 300 mg l-1) were examined on in vitro pollen germination of 4 date cultivars (Ghanami Ghermez, Nar Pakhotah, Sabz Parak and Vardi). The results showed thattype and levels of treatment significantly affected the pollen germination rate in all examined male cultivars.  It was found that pollen germination in all cultivars was decreased by increasing calcium nitrate concentration up to 300 mg l-1 while germination was increased with increase in boric acid and potassium nitrate levels up to 100 mg l-1 and then gradually decreased up to 200 and 300 mg l-1, respectively. The pollen germination was significantly higher at 200 mg l-1 of MgSO4 than other concentrations. Significant differences in germination rate were found among cultivars in different culture media. With optimum concentrations of B, Ca, Mg and K, the highest pollen germination was obtained for Nar Pakotah cultivar

Iran is the origin center of grape and a large number of commercial grape cultivars are grown with different biochemical properties. In order to study and compare the biochemical attributes and antioxidant activity of some grape cultivars, 7 grape cultivars including Bidane Sefid, Bidane Ghermez, Tabarze Sefid, Tabarze Ghermez, Ghezel Ozum, Lale Ghermez and Rish Baba were prepared from a uniform grape garden in Urmia city. Soluble solids content, titratable acidity, TSS/TA, vitamin C, total phenolics content, polyphenol oxidase enzyme activity, antioxidant activity and fruit juice were evaluated. The results showed a significant difference between the studied cultivars for all measured traits. The highest soluble solids content and organic acids were found in Bidane Ghermez cultivar. The highest TSS/TA and vitamin C values ​​were recorded in "Rish Baba". Also, the highest phenolics content and polyphenol oxidase activity were observed in Tabarze Ghermez and Lale Ghermez cultivars respectively.  Total antioxidant activity varied from 255.9 (mmol Fe 2+ per 100 g fresh weight) in Tabarze Ghermez cultivar to 294.3 (mmol Fe 2+ per 100 g fresh weight) in Bidane Sefid.

The quality of fruits decrease after harvest due to the release of ethylene, water lost and other internal factors. Attempts for reducing postharvest losses has led to introduce of various packagings, this study was carried out to compare and evaluate the storage life of five grape varieties including: "Bidaneh Sefide", "Bidaneh Ghermeze", "Lal", "Sahebi" and "Fakhri". In this experiment, disposable containers, non-packaging, washing before storage and no washing were used as treatments. Respiration rate, fruit juice, soluble solids, organic acids, pH, anthocyanin content, storage life, shrinkage, browning and decay index and water loss were evaluated. According to the results, "Bidaneh Ghermeze" packed in disposable showed the longest of storage life. This treatment with the lowest respiration rate (0.03 mgCO2/kg.hr), browning index, shrinkage, decay index and water loss with 3, 5, 0 and 9 %, respectively showed higher storage life compared to other treatments. "Sahabi" fruits with the highest respiration rate (0.16 mgCO2/kg.hr) and deterioration and %60 shrinkage had the lowest storage life in washing treatment before storage. This treatment had the lowest market ability and anthocyanin content. Based on the results of this research, "Bidaneh Ghermeze" and "Fakhri" cultivars showed better storage life compared to the other cultivars and washing before storage or using of disposable packs are not sufficient to decrease grape post harvest losses.

Ghezel Ouzum is a commercially important cultivar with red crispy and juicy berries. In In vitro Micropropagation of woody plants such as grape, the proliferation stage has a high importance. Hence with different methods it has been attempted to achieve a successful way to increase the propagation rate. In this research the effect of low molecular weight chitosan on proliferation of Ghezel Ouzum grape was studied. For this purpose, the MS medium containing benzyl amino purine 0.5 mg L-1 (BAP) and 0.01 mg L-1 Indole butyric acid (IBA) and various concentrations of chitosan (0, 10, 20, 40, and 80 mg L-1) were used in a completely randomized design with five replicates. The results showed that the effect of chitosan on in vitro proliferation of Ghezel Ouzum grape cultivar was significant, so that the addition of chitosan to the culture medium increased  the proliferation rate of shoots. According to the results, chitosan concentration of 40 mg L-1 showed better results compared with the other concentrations and control and increased the number of lateral shoots, shoot length, leaf number, leaf area, dry weight of plant biomass, and chlorophyll content in produced plants. Based on these results, given the favorable properties of chitosan, it can be used as a growth stimulator for increasing in vitro proliferation of this grape cultivar.