Volume 27 (2019): Issue 1 (June 2019)

Two plum cultivars ‘Record’ and ‘Empress’ and one prune cultivar ‘Common Prune’ were planted in spring 2014, spaced at 4.5 × 1.5 × 2.0 m, to be trained to the “Y”- and “V”-trellising systems for mechanical harvesting of dessert fruits with a canopy-contact harvester. The applied trellising systems were compared with the standard central leader system at the same spacing. Trellised trees showed a tendency to grow less well than leader-trained trees, but during the four years of training, they created a higher canopy volume than the control trees because of their spreading form. Trellised trees were able to give yields comparable to those of standard trees. Light distribution within the tree canopy was acceptable in all the training systems. After 4 years of training, the trees were suitable for mechanical harvesting. The effectiveness of mechanical harvesting varied from 85% to 90%. The quality of the fruits harvested with a canopy-contact harvester was comparable to that of manually picked fruits. The consumption of quality of fruits after mechanical harvesting rated on a 5-grade scale was 0.5 grade lower than that of manually harvested fruits. These fruits were acceptable in the local fruit market. Mechanical harvesting was 10–30 times faster compared to manual picking. The cost of the trellising system calculated per 1 ha was 2.0 times higher than that of the standard system.

One of the methods for breeding of fruit trees is the identification and selection of superior genotypes in different regions. Owing to climate changes in the recent years and the urgent need to changing the pattern of cultivation, it is essential to use adapted species to climatic conditions. Barberry is one of the plants that have been naturally grown in some areas of Isfahan province. For accessing the promising genotypes of barberry in Isfahan province, this research was carried out in the main areas of barberry growing. For this purpose, some physiological and pomological traits of about 100 barberry genotypes from different regions of Isfahan province were evaluated according to Union for the Protection of New Varieties of Plants descriptor. Evaluated traits were recorded in each year in four stages, including the physiological dormancy of the tree, the flowering, the vegetative growth of the tree as well as the ripening and harvesting time of berry stages from 2014 to 2016. According to the results, seven genotypes were selected, including Dolat Abad, Semirom, Dehaghan, Red leaf, and Evergreen genotypes as well as two wild genotypes. The results showed that the berry length ranged from 1.06 to 9 mm and the berry width ranged from 0.4 to 5.2 mm. The dried barberry per kilogram of fresh berries was between 200 and 700 g. The leaf length and leaf width of the studied genotypes were in the range 26–81 and 9–26 mm, respectively. The thorn length varied between 9 and 91 mm. The seed length and seed width were recorded in the range 0–4.5 and 0–2.6 mm, respectively. Dolat Abad and Dehaghan genotypes had the highest berry length and berry width, respectively. The most dried barberry per kilogram of fresh berries belonged to these two genotypes. Evergreen and Red leaf genotypes had the highest leaf length and leaf width, respectively. The highest seed length and seed width were observed in two wild genotypes of collected barberry. The results of correlation analysis of traits showed that tree growth vigor had a significant positive relationship with berry size, thorn length, seed length, and seed width. Berry firmness had negative correlation with berry length and berry width. On the basis of cluster analysis, genotypes were placed in three groups, so that genotypes from Dolat Abad, Semirom, and Dehaghan regions were placed in a same group. Red leaf and Evergreen genotypes with ornamental application were in another group, and two wild genotypes were also placed in the third group. Eventually, Dolat Abad, Semirom, and Dehaghan genotypes were introduced as the promising genotypes because of seedless berry with the highest berry length and berry width and the most dried barberry per kilogram of fresh berries.

Paclobutrazol (PAC), as a commonly used plant regulator, has the important function of improving the plant’s stress resistance. Sequoia sempervirens Endl. is a large caliber, fast-growing timber species and one of the world’s five major landscaping tree species. This study researched the effects of spraying PAC on the growth and photosynthetic activity of S. sempervirens seedlings. The results showed the plant height and the plant crown diameter were decreased significantly with the increase in PAC concentration (500 – 3,000 mg·dm⁻³). However, the ground shoot diameter, net photosynthetic rate, stomatal conductance, inter-cellular CO₂ concentration, transpiration rate, actual photochemical quantum yield, and photosynthetic electron transport rate all showed the trend of increasing first reaching the maximum at 2,000 mg·dm⁻³ and then decreased. Water use efficiency showed the opposite trend. Spraying 2 times was better than once. The conclusion suggests that PAC can protect the photosynthetic activity and improve the resistance of S. sempervirens seedlings under natural cooling and draught in autumn and winter.

Use of hydroponics is increasing because of its ability to be used for year round vegetable production using an environmentally sustainable system. Management of solution pH is an important challenge in hydroponics systems. Our objective was to quantify the effects of various pH modifiers on growth and nutrient uptake of leafy greens and stability of nutrient solution’s pH. Lettuce, basil, and Swiss chard were transplanted into an Ebb and flow system, and nutrient solution pH was maintained using three different pH modifiers (pH Down, lime juice, or vinegar). The nutrient solution’s pH was maintained between 5.5 and 6.5. pH Down resulted in the most stable solution pH and required the least amount of product used when compared to lime juice and vinegar. The cost of using phosphoric acid or lime juice was greater than that of using vinegar. Vinegar reduced the yield of all crops in comparison to pH Down. When compared to pH Down, lime juice reduced the yield of basil and Swiss chard but not that of lettuce. Therefore, growers can use lime juice as an alternative to pH Down in lettuce production but not for basil and Swiss chard, while vinegar would not be recommended for any of the crops studied.

Iran is one of the main diversity centers and origins of pistachios in the world. Pistachio cultivation spread first within the ancient Persian Empire and then moved gradually westward. Knowledge of the genetic relationships among wild and cultivated varieties of pistachio is important for the efficient utilization of the available germplasm resources. Three molecular marker strategies, namely, inter-simple sequence repeat (ISSR), inter-retrotransposon amplified polymorphism (IRAP), and retrotransposon microsatellite amplified polymorphism (REMAP), were used to study the genetic relationships among 35 pistachio accessions including 15 wild-type genotypes of Pistacia vera and 20 important cultivars from Iran. According to the results, high levels of polymorphism were observed for all three marker systems. REMAP and IRAP techniques had the higher mean values of genetic relationships parameters than ISSR technique. The results from this study showed that the 5′LTR2, Sukkula, Sukkula + UBC855, and 5′LTR2 + UBC811 primers were the most informative and could be used to evaluate the genetic relationships of pistachios accessions. Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) properly separated the accessions and divided them into four main groups. The presence of most cultivated genotypes in a group indicates genetic erosion of cultivated pistachio in Iran. Wild-type genotypes of P. vera are located in different clusters indicating the high diversity of the genotypes. The results provide useful genetic information about wild pistachios in northeastern of Iran and indicate that the use of wild pistachios in breeding programs could be useful for generating new genotypes with interesting characters.

The effect of silica nanoparticles (SiNPs) preservative solutions on the postharvest quality of rose cut flowers was investigated in this study. SiNPs were used at the concentrations of 0, 1, 2, and 3 mg·dm⁻³. Treatments of SiNPs increased flower longevity compared to untreated flowers. Relative fresh weight, relative water content, and water uptake were improved because of SiNPs treatments. The enhancement in chlorophyll content, total soluble sugars, as well as total phenol and flavonoid contents were positively correlated with SiNPs treatments. Malondialdehyde (MDA) content significantly increased by control roses relative to treated ones. Activities of peroxidase (POX) and polyphenol oxidase (PPO) enzymes significantly increased because of SiNPs treatments compared to the control. The treatment of 2 mg SiNPs·dm⁻³ maximized the longevity and improved the postharvest quality of cut roses. The results obtained suggested that SiNPs treatments could improve the longevity and postharvest quality of cut roses by reducing lipid peroxidation and motivating antioxidant machinery, therefore, retaining the membrane integrity.