مجله علوم باغبانی ایران
سال چهل و سوم شماره 3 (پاییز 1391)

Consumers prefer seedless grapes for table and raisin grape industry. Release of new superior seedless grape cultivars is one of the main objectives in grape breeding programs. Embryo rescue is one of the techniques to develop a new seedless cultivar. Therefore, in this study, the effects of bud flower spraying with BA (50 ppm) and CCC (200 ppm) before blooming were studied in ‘Flame Seedless’ ‘Perlette’ and ‘Askari’. Ovules were extracted 50 days past pollination, cultured on medium and then their embryos were dissected out of ovules and cultured in NN medium. Recovery and germination of embryos were evaluated. Spraying flowers with BA and CCC resulted in 32.94 and 32.05% of recovered embryos and 26.76 and 27.05% of germinated embryos, respectively, which both had significant differences with control.

An experiment was conducted to study the effects of different concentrations of Silver thiosulfate (STS) (0.25, 0.5, 1 and 2 mM), Sucrose (2.5, 5, 7.5 and 10 %), Humic acid (100, 500, 1000, 5000 and 10000 ppm) and Banzyl adenine (5, 10, 20 and 40 ppm) on vaselife of cut ‘Tempo’ carnation flowers. The experiment was arranged in a compeletly randomized design. The results of means comparison indicated that STS at rates of 0.25 and 0.5 mM exerted significant (p<0.05) and positive effects on vase life, solution uptake and relative fresh weight as compared to control. However, the highest vase life (24.7 days) was obtained by STS at the rate of 0.25 mM, which was significantly (p<0.05) more than control (15.8 days) and other treatments. Application of BA and Humic acid not only did not increase vase life, but also at their high concentrations (Humic acid at rates of 500-10000 mg/l and BA at rates of 10-40 mg/l) slightly decreased the flower’s vase lives. Sucrose as well as other treatments did not affect the other evaluated traits

High yield of top quality crop is a prerequisite for profitable production of greenhouse produced cucumber. On the other hand, because of water deficit in Iran it is necessary to economize in this scarce and valuable input. An experiment was carried out in the experimental greenhouse of University College of Agriculture and Natural Resources, University of Tehran to optimize water use in soil culture of greenhouse cucumber, applying drip irrigation as a irrigating system and tensiometer as the moisture measuring instrument. The aim of this research was to determine a suitable starting point of soil water potential at which irrigation pumps would start to operate and while growth and yield of greenhouse cucumber would be at its optimal state. Three water potentials for starting the irrigation system (-25, -45, and -65 centibar) were compared. Results showed the volume of applied water was 1.24 times higher in the -25 centibar treatment than in the -45 one and 2.03 times higher than that in -65 centibar treatment. The treatments had significant effect on water use efficiency. Decrease in volume of applied water resulted in increase of water use efficiency. Water use efficiency was 48 percent higher in -65 centibar treatment in comparison with -25 centibar and 46 percent higher in the -65 centibar as compared with -45 centibar treatment. Increase in soil water enhanced the vegetative growth. Yield quality was acceptable and not seriously affected by different soil moisture levels. Because of better water use efficiency of -65 centibar treatment as compared with the other ones and no serious change in fruit quality and quantity parameters, it can be concluded that a pump starting point of -65 centibars is recommendable for soil based greenhouse cucumber irrigation.

Melon is an economically important crop and Iran is considered as its diversity center. To investigate gene action, heritability and number of effective factors for yield and related traits, six generations, namely: P1, P2, F1, F2, BC1, and BC2 of two crosses of Mirpanji × Tashkandi and Mirpanji × Abasali were produced and evaluated in the spring of 2008, applyig a complete block design of three replications. Significant differences were observed among generations for all the traits. In Mirpanji × Tashkandi, a positive significant cross heterosis over the more dominant parent was found for yield as well as for the acceptable yield (13.76 and 27.34% respectively). Estimates of gene effects as based upon a six-parameter model (according to Mather and Jinks in Mirpanji × Tashkandi cross) showed that a simple additive-dominance model is adequate for the evaluated characteristic except for days to maturity and for fruit length. Both additive and dominance gene effects were important in the governing and acceptable yields in Mirpanji × Tashkandi cross, while epistatic genetic effects were not important. Chi square and Joint Scaling Tests in Mirpanji × Abasali cross indicated that a simple additive-dominance model was not adequate for the evaluated characteristic, while epistatic genetic effects did prove their importance.

The effect of gibberellic acid (GA3) spraying on some characteristics of cyclamen flowering trend during the second flowering year was investigated. GA3 sprays were applied in concentrations of 0, 20, 30, 40, and 50 mg/l. The trial was carried out as a randomized complete design of three replications. The total flower count, flower count during the flowering peak, days from spraying to flowering peak, petal length, flower spout diameter and petiole length were measured. Results showed that different concentrations of GA3 had no effect on the total flower count throughout the flowering period. The highest flower count during the flowering peak was achieved with 40 mg/l concentration of GA3. The floral display was also incredibly increased using this concentration of the GA3. Increase in GA3 concentration, resulted in decreasing the days from spraying to flowering peak. Use of 50 mg/l concentration of GA3, resulted in a minimum day count from spraying to flowering peak. On the other hand, this concentration of GA3, resulted in an inordinate of the increase petiole length, lowering the floral display. Petal size and flower spout diameter were not affected by different concentrations of gibberellic acid.

The present research was conducted to determine the percent self-incompatibility in some Asian pear (Pyrus serotina Rehd.) as well in European pear (Pyrus communis L.) cultivars. The experiment was carried out during 2006 and 2007 growing seasons. Pollen grains were collected and tested for viability using in-vitro pollen culture. For microscopic examination of pollen tube growth in the style, pollinated flowers were sampled and fixed in the FAA solution after 48, 72, 96 and 120 hour post pollination. At the time of flowering stage and during both seasons, Asian and European pear cultivars exhibited a reasonable overlap of flowering. Pollen viability test on Asian pear (as well as microscopic examination of pollen tube growth) in all the studied cultivars showed 55 to 70% pollen germination, indicating that pollen grains involved in the experiment were healthy and viable, although in most of the studied cultivars pollen tube stopped growth at a one third point to style ending. Results as based on the final fruit set (in-vivo test) showed a fruit set of less than 5% for Asian, European and as well for the native studied cultivars. So, one can conclude that all the studied cultivars were self-incompatible. Therefore, as for the future breeding programs, cross pollination is suggested within Asian pears as well as among Asian and European pears to create and produce working material of enough variability. In addition, in order to produce higher yields, it is necessary to carry out control pollination experiments (utilizing various cultivars as pollen and seed parents) to determine cross-compatible groups for the newly established Asian pear orchards in Iran.

Artemisinin, a secondary metabolite, is produced by Artemisia annua L. plant and is nowadays, the most effective drug in the treatment of malaria. This component and its derivatives are also used against hepatitis B and different types of cancers. Chemical synthesis of artemisinin is possible but because of its complex structure and low yield, it is not economically feasible. Since this plant serves as the only commercial source of artemisinin production while also producing it at very low levels, efforts to increase the production source of this valuable drug are indispensable. In this study, the effects of four hormones namely: gibberellic acid (GA3), cytokinin(2-iP), methyl jasmonate(MeJA) and salicylic acid(SA) on artemisinin production were studied at different time points following treatments. It was observed that MeJA had the highest positive effect on artemisinin production as compared to the other three hormones, and in a descending order of effect there stood 2-iP, SA, and GA3. Therefore, due to the more provoking and uniformly increasing effects on artemisinin content throughout the study, MeJA is a proved to be a promising and suitable candidate for further studies in field applications.

To study the effects of postharvest treatments of spermidine and putrescine on storage quality of ‘Hayward’ kiwifruit, the present research was performed. In November 2010, fruits were hand picked from Fajr Orchardist Corporation in Sari and transported to postharvest physiology laboratory. Fruits were dipped for 4 minutes in either spermidine or putrescine solutions (0.5, 1.0 and 1.5 mM), and distilled water being used as control. The design of the experiment was a complete randomized one of 4 replicates in each treatment. Following a two month period of storage (at 5°C and 90±5% relative humidity), results showed that postharvest treatments of spermidine and putrescine can beneficially affect qualitative characteristics of ‘Hayward’ kiwifruit and for each treatment, the degree of effectiveness depends on polyamine utilized and the concentration applied. In comparison with control, treated fruits benefitted from lower weight loss and TSS, higher total acidity, vitamin C, and fruit firmness. As regards pH, there were no significant differences observed between treated and control fruits. In total, spermidine at its 1.5 mM concentration was the most suitable treatment in maintenance of quantitative and qualitative characteristics of kiwifruit.

Ziziphora tenuior, named Kakooti in Farsi, is one of the aromatic and medicinal plants of a wide distribution in Iran. In this study, RAPD molecular markers, (by utilization of 16 primers) was applied to determine the genetic diversity of 39 samples of Ziziphora tenuior from 21 geographical regions in Iran. A number of 100 polymorphic bands out of 110 amplified ones was produced and analyzed through NTsys software. Jaccard's similarity coefficient was employed to calculate similarities among the samples. Calculated similarity based on the polymorphic bands, stood in the range of 0.19 to 0.77 with a mean of 0.43. Most amplified polymorphic fragments (12) were related to the primer TIBMBA-06, while the primer TIBMBB-13 carried the lowest (3) amplified polymorphic bands. Mean number of amplified bands for primers was 6.9, while the mean number of polymorphic bands was 6.3. Cluster analysis was performed based upon similarity matrix and UPGMA method. According to cluster analysis within the similarity coefficient of 0.43, Ziziphora samples were divided into 6 groups. Based upon similarity matrix, the lowest similarity (0.19) was found for two samples from Mashhad and Eslamieh Yazd with high geographical distance whilst the highest similarity (0.77) found between two samples from Yasuj within the same geographical region. The results finally indicated high genetic diversity among the studied genotypes.

Paclobutrazol was utilized to analyze its role in water stress amelioration and post drought recovery of container-grown pear (Pyrus communis cv. Biroti) saplings. Following planting, paclobutrazol was applied as soil drench at concentration of 0, 0.15 and 0.3 mg per pot. Three months following planting, saplings were subjected to three water stress treatments of: 0, -0.4 and -0.8 MPa. Control treatment was subjected to daily irrigation. Irrigation was applied when soil water potential reached -0.4 and -0.8 for the water stress treatments. All traits were recorded during water stress as well as two day following rewatering. Results showed that Paclobutrazol effectively slowed down growth parameters. Paclobutrazol decreased saplings, growth, mean leaf area, trunck diameter, shoot and plant dry weights. But, significant differences were not observed between 0.15 and 0.3 gr/pot paclobutrazol treatments. Paclobutrazol did not affect membrane stability index. Leaf chlorophyll (a, b and total) contents were affected by paclobutrazol and water stress treatments, but their interaction was not significant. Total leaf chlorophyll content was higher in 0.15 and in 0.3 gr/pot paclobutrazol treatments than in control. Leaf proline (73.4 µmol/gr dry weight) and total carbohydrate (2.35 gr/100 gr dry weight) contents were recorded as the highest in -0.8 MPa water stress treatment. Photosynthesis rate, stomatal conductance and transpiration (4.59 molm-2s-1(were recorded as least in -0.8 MPa water stress treatment. These parameters were identical at the beginning of water stress treatment and withing two days after rewatering. When compared with non-paclobutrazol-treated controls, paclobutrazol treatments contained higher sub-stomatal Co2. In conclusion, the results showed that paclobutrazol induces more water stress tolerance in pear (cv. Biroty) by affecting the vegetative, biochemical and gas exchange traits.