مجله علوم و فنون باغبانی ایران
سال هجدهم شماره 1 (بهار 1396)

According to nutritional disorders in Iran citrus orchards and need to investigate the effects of nutrient elements and growth regulators that have the ability to improve quality and quantity of crop, this study was conducted to investigate the effect of calcium chloride, potassium chloride and salicylic acid on quantitative and qualitative attributes of ‘Washington Navel’ orange fruit. The experiment was conducted using randomized complete block design (RCBD) with four replications in Janat Shahr, Darab, Fars province, during two successive years. Treatments of experiment included calcium chloride (1.5% and 3%), potassium chloride (1.5% and 3%), salicylic acid (0.015%, 0.03% and 0.045%), combined treatment of calcium chloride, potassium chloride and salicylic acid and control. The spray of aqueous solutions was applied at the end of the first stage of fruit growth, one month after full bloom (fruit diameter was 20 mm) and repeated in late September. Results showed that foliar application of calcium chloride, potassium chloride, salicylic acid, and combination of these treatments had different effects on fruit quality characteristics at the harvest time. Foliar application of potassium had no significant effect on fruit peel potassium. However, peel calcium increased with spraying of calcium chloride. Foliar application of salicylic acid up to 0.03%, significantly increased calcium and potassium contents of fruit peel. Calcium chloride and salicylic acid treatments had the greatest positive effect on fruit quality characteristics. Although, potassium did not have significant effect. The effect of treatments on hue angle, fruit juice content, TSS and antioxidant activity were not significant. Calcium chloride and salicylic acid had a positive effect on the qualitative properties of juice. Calcium chloride at 1.5% and salicylic acid treatments at 0.03% had the most positive effect on the quality characteristics (antioxidant activity and total phenol). Combined treatments had positive effects, but the effect of calcium and salicylic acid was more effective treatments.

Water availability is one of the most limiting environmental factors on plant growth. Drought stress is one of the main stresses that inhibit the growth of plants due to mainly disturbance of the balance between production of reactive oxygen species and antioxidant defense morphological and physiological response of bermudagrass, tall fescue turfgrasses and their seed mixture under drought stress condition. This study was conducted in a completely randomized factorial design by different irrigation levels (100, 75, 50 and 25% of field capacity) on bermudagrass, tall fescue and their seed mixture (bermudagrass %20 and tall fescue %80). Each treatment had four replicates. Results showed that decreasing in field capacity reduced visual quality, fresh and dry weights of shoot and root, chlorophyll content in bermudagrass, tall fescue of turfgrasses and their seed mixture. Decreasing in field capacity increased proline content and peroxidase enzyme in turfgrasses. Ascorbate peroxidase, superoxide dismutase and catalase enzymes activities significantly increased with decreasing in field capacity from %100 to %50 then, declined in %25 FC treatment in turfgrasses. The highest activity of antioxidants was observed in bermudagrass. Due to the lack of sufficient available water resources in Iran, using turfgrass seed mixtures comprising different genotypes and rates can be recommended.

Mutation by gamma radiation is used as a new technology to improve some quality traits in fruits. In this research, the effect of gamma radiation in scions of kiwifruit with different doses (0, 30, 40, 50, 60, 70 and 80 Gray) on the physicochemical properties of kiwifruit was studied. For this purpose, chisel grafting of gamma treated scions were done on kiwifruit vines in winter 1391 and after a year of no fruiting (1392), in 1393, the fruits were evaluated at harvest time and intervals of one month in the cold storage for 3 months. The results showed that fruits obtained from treated scions with dose of 40 gray of gamma radiation had the highest firmness, highest weight and lowest weight loss at harvest and during storage. Vines with treated scions by doses of 70 and 80 gray of gamma radiation did not have any fruits and remained in vegetative stage. The treatments of 50 and 60 gray of gamma radiation caused severe deformation and deep split in kiwifruits and these lost their marketability. Therefore, the firmness of kiwifruit during storage is the most important factor in the potential storage and exports, due to the positive effect of radiation of 40 gray on this factor at harvest time and during storage, as well as an increase in fruit weight, fruit yield and reduce water loss, it seems to be effective in positive changes of quality of the fruit.

In the current work the salinity stress tolerance of shootlets of two pear cultivars Harrow Sweet and Bartlett was studied and compared under in vitro culture condition. Salinity stress was imposed into the QL medium using different concentration of NaCl (0 as control, 80 and 120 mM) for six weeks. Shoot length, fresh and dry weight as well as leaf numbers of the shootlets were negatively affected by salinity stress. However, these effects were more pronounced in shootlets of Bartlett than Harrow Sweet. The highest salinity injury index (SII) was observed at 120 mM NaCl in the value of 1.41 and 1.72 units in cultivars Harrow Sweet and Bartlett, respectively. The activities of both tested antioxidant enzymes, superoxide dismutase (SOD) and peroxidase (POD) enzymes were increased by salinity treatments. These activities at 120 mM NaCl were higher in Harrow Sweet than other ones. In terms of maintaining high proline and Kﳖ contents in the leaf tissue, Harrow Sweet showed more favorable situation in comparison with Bartlett cv. Differential tolerance to the salinity stress, with the high amount in 'Harrow Sweet', was displayed in two pear cultivars based on the majority of evaluated criteria.

In order to study the effects of spermidine (0.5 and 0.75 mM) and methyl jasmonate (0.25 and 0.5 mM) on the vegetative and reproductive growth of snake melon, an experiment was conducted using a randomized complete block design with 3 replications in College of Agriculture, Isfahan University of Technology. Each replication consists of 8 plants. Each plant (5-7 leaf stage) was sprayed with 100 ml of related solution and distilled water was used as a control. Characteristics including the date of flowering, the number of male and female flowers, yield, fruit characteristics were measured during and at the end of the experiment. Results showed that the plants treated with 0.5 mM spermidine, had the highest number of female flowers and the highest ratio of female to male flowers and they had the highest number of fruits in the plant. Also, the plant related to this treatment produced male flowers sooner than other plants. Overall, srpermidine increased vegetative growth and the photosynthetic surface of plants.

One of the most important problem of citrus fruit production in south of the Iran is sunburn of fruit during the summer. To prevent leaf and fruit burns an experiment was conducted as factorial in a randomized block design in a commercial orchard in Junan Darab region, Fars province, Iran, with four replications for two years (2012-13). Factor one was kaolin at 0, 3, and 6%, factor two was tree direction (north and south) and factor three was time of application. The results showed that kaolin at 3% significantly reduced tree transpiration, but had no significant effect on total leaf chlorophyll, Fv/Fm, photosynthetic rate and stomatal conductance. Kaolin at 3 and 6% significantly reduced the area, intensity and percentage of sunburn up to 54%. We recommended kaolin at 3% without influence on photosynthesis for sunburn protection of citrus fruit specially Navel orange in commercial orchards during growth and development.

Erwinia amylovora bacterium is the cause of Fire blight disease and is one of the most important damage factors in pome fruit orchards. Currently utilizing resistant varieties and rootstocks are introduced as most important way to fight against these bacteria. Present study aimed to evaluate the resistance rate and study the induced biochemical changes in four pear vigorous rootstocks including Konjuni, P. betulifolia, Dargazi and Gh1 rootstocks in vitro conditions. For this purpose, each four rootstocks explants inoculated with a mixed of Erwinia amylovora strains. Induced morphological and biochemical changes in rootstocks were evaluated at 24 hours intervals for 4 days. According to results, Dargazi and P. betulifolia rootstocks were more resistant than other two rootstocks in vitro conditions and exhibited lowest necrosis percentage. Also, activity of antioxidant enzymes including peroxidase and polyphenol oxidase in these two rootstocks increased more than Konjuni and Gh1 rootstocks. In Dargazi rootstock, polyphenol oxidase had more activity whiles in P. betulifolia rootstock, peroxidase enzyme had more activity. Totally, based on results of present study, Dargazi and P. betulifolia rootstocks could be introduced as resistant and semi-resistant rootstocks and Konjuni as the most sensitive rootstock to fire blight disease.

Identification of grape cultivars based on fruit qualitative and nutritive indices in order to targeted supply in domestic and foreign markets is very important. In this research, quantitative and qualitative traits of five commercial grape cultivars including Bidaneh Sefid, Bidaneh Qermez, Fakhri, Shahani and Mirzaei, was evaluated in a commercial vineyard located in Jozan village of Malayer city under a completely randomized blocks design with five treatments (cultivars) and three repeats (two vines at each repeat). Vines with same pruning and growing conditions were selected and checked at specified intervals until harvest time. Fruits harvested based on °Brix index in September and fruits quantitative traits including cluster weight, 20 berry weights, number of seed per berry, skin weight to berry percentage, dry weight, density and fruit qualitative traits such as pH, titratable acidity (TA), total soluble solid (TSS), anthocyanin, vitamin C, flavonoids, total phenol, phenolic acids and antioxidant capacity, and minerals including of potassium, magnesium, iron and zinc of fruit was measured. Based on results, a significant difference (p≤0.01) was found among all cultivars regarding to cluster weight, 20 berry weights, number of seed per berry, skin weight to berry percentage, dry weight and density. The highest cluster weight and density was related to Mirzaei cultivar and the lowest was found in Bidaneh Qermez cultivar. In terms of dry weight, the highest value was observed in Fakhri cultivar and the lowest of it was found in Bidaneh Sefid cultivar. Cultivars showed a significant difference (p≤0.01) in TSS, anthocyanin, flavonoids, total phenol and antioxidant capacity. The maximum TSS was related to Fakhri cultivar and the lowest was related to Shahani cultivar. The highest and lowest antioxidant contract was found in Shahani and Fakhri cultivars, respectively. Moreover, the highest and lowest flavonoids contract observed in Shahani and Mirzaei cultivars in respectively. Among of all cultivar Shahani showed the highest total phenol content. In terms of phenolic acids, the highest gallic acid, catechin, resveratrol, quercetin, ellagic acid and caffeic acid was found to be higher in Shahani cultivar in compared to other cultivars.

Grape is one of the most important fruit crops in which seedless cultivars have been more interested among consumers. Iranian seedless grape cultivars are limitted and have faced some undesirable traits. Therefore, breeding them to achieve superior seedless cultivars is necessary. In order to evaluate 13 hybrids obtained from crosses among four seedless male parents and seven seeded female parents and comparing them with Iranian native seedless cultivars (Bidaneh Sefid, Bidaneh Ghermez, Askari, Yaghouti), this work was conducted in randomized complete block design with eight replications during years 2014 and 2015 in College of Agriculture and Natural Resources, University of Tehran. Hybrids were 4 to 5 years old and trained to figure of self-supported. Comparisons of data showed significant differences among hybrids for all measured traits. According to panel test hybrids were derived in to groups of seedless and semi seedless. Hybrids B98 and Q45, had the highest berry size while Yaghouti had the lowest. Hybrids B98 and Q45, had the gratest berry weight. Bidane Ghermez had the highest ratio of sugar to acid. Hybrids L125, B98 had the highest and Bidane Ghermez had the lowest single seed fresh weight. Considering all qualitative and quantitative traits, hybrids I21, S51, B98¡ L127¡ Q45¡ I73¡ R80¡ S55 and L125 were selected as superior hybrids.