IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2007 | Volume:8 | Issue:1|Papers Count:7

Ficus carica L. ‘Sabz’ is the most important commercial and dried fig cultivar in Iran. It needs to be pruned using special techniques in rain-fed conditions. In this study, in order to determine the best method and intensity of the annual pruning, treatments of winter pruning including thinning out (T) and heading back (HB) of 1-year old branches, shoots summer pruning (SP), and combination of them  were compared in a randomized complete block design. Results showed that severe thinning out of 1-year old lateral branches (ST) along with HB significantly increased shoots length compared to SP treatments and light thinning out of 1-year old lateral branches (LT) treatment. Summer pruning decreased shoot length which is useful to maintain small crown size and optimum soil moisture use in rain-fed conditions. Severe thinning out along with HB increased late mature fruits percentage. It was significantly different with all the T treatments alone and LT treatment. This treatment is not recommended because of its fruit ripening at unsuitable climate conditions in late harvest season. The traditional pruning method in Estahban, moderate thinning out of 1-year old lateral branches (MT), increased the weight of light brown dried fruits and average fruit weight that significantly differed with MT along with HB treatment. Severe thinning along with SP increased dried fruit diameter that significantly differed with all of T along with HB treatments. Severe thinning out increased yield that significantly differed with most of the treatment, however, but it had not significant difference with MT.

An investigation was carried out to study the effect of 1-MCP on vase life extention and postharvest quality in cut carnation cv. ‘Tempo’. Three 1-MCP concentrations (0, 50 and 100 nl. l-1) were imposed on 108 cut carnations. In this study, in addition to determination of best concentration of 1-MCP, optimum time for peak of ethylene production was determined. In this experiment, characteristics such as vase life, dry matter of cut flowers and ethylene production were recorded. Cut carnations were kept in the postharvest room where the temperature was 20±2°C with 60-70% RH, 15-20 mmol.s-1 m-2 light density and 12 hr photoperiod. The results showed that control plants and other treatments (including 50 and 100 nl. l-1) received to peak of ethylene production at 6th, 12th and 24th hr, respectively. The difference between treatments was significant at 1% according to studied traits. Meanwhile 50 nl. l-1 1- MCP with 18.3 % dry matter and 16.3 days vase life was the best treatment and showed a significant performance at 5% and 1% levels, respectively, compared to control.

High rate of root pressure is one of the main reasons of walnut grafting failure at early spring. In this experiment the effects of factorial combination of three seedlings vigor and three methods of root pressure control was investigated on the sap flow rate (SFR), grafting success percentage (GSP) and scion growth, in a completely randomized design with three replications. The effect of seedling vigor on the SFR trends and its correlation with the environmental variables during a 4-week period was studied as a separate experiment. According to the results, the SFR was similar for all of three groups of seedlings at the first week but, the trend of SFR was significantly separated during later weeks of measurements, so that it was decreased significantly in the case of low vigorous seedlings as compared to the vigorous and medium-vigorous seedlings (P<0.01). Also the rate of sap flow showed a positive correlation (r=0.98) with the minimum temperature of a day before of its measurement. The relatively late decline of SFR in low vigor seedlings did not significantly affect the GSP, but in combination with the one week of grafting delay resulted to the non-significant increase in the GSP as compared to vigorous seedlings (P<0.01). In addition, covering graft union with moist sawdust as well as grafting delay for one week resulted to the highest GSP (80-90%) independently from the seedling vigor. The growth rate of scions 45 days after grafting was affected significantly by the seedlings vigor (P<0.05). Thus, by controlling the root pressure via delay in grafting time and covering graft union by moist sawdust or avoiding usage of very vigorous seedlings of forest walnut ecotypes in the nurseries, it could be possible to obtain about 90% of GSP as well as a relatively significant reduction of scion growth.

The effects of some oxidative stresses specially drought and salinity stresses on regulation of  a-dox1 and a-dox2  genes expression were investigated in tomato roots under greenhouse and hydroponic conditions. To asses the role of abscisic acid (ABA) and ethylene three genotypes including wild type ‘Ailsa Craig’ (‘AC’), the near isogenic ABA deficient Flacca (‘Flc’) strain and the ethylene receptor mutant Never ripe (‘Nr’) were used. Roots of stressed tomato plants were harvested and subjected to RNA extraction and RNA- hybridization with a-dox probes. The results showed that none of the stress treatments affected the regulation of a-dox2 gene expression. Salt (24 hr exposure of 170 mM NaCl) and drought (36 hr exposure) stresses upregulated   a-dox1 expression in ‘Flc’ and AC roots. In roots of ‘Nr’ high level of   a-dox1 expression was detected following salt treatment but, drought had no effect on its response. The greater upregulation of   a-dox1 in ‘Flc’ roots is most likely due to an increase in ethylene levels in this genotype. In adult plants, different concentrations (0, 100, 170 and 300 mM NaCl) of salt treatments had no effect on a-dox expression in ‘AC’ and (‘Nr’ plants. However, over expression of a-dox1 was detected at 170 mM level in ‘Flc’ roots. Different times (6 hr, 1, 3 and 6 days) exposure of salt treatments was carried out on ‘AC’ and ‘Flc’ roots. Upregulation of   was observed at 1 day exposure in both genotypes. Furthermore, overexpression of this gene was detected at 6 hr exposure only in ‘Flc’ roots. The results of greenhouse experiments showed that regulation of   were depended on plant growth stages due to change in ethylene contents. The expression of  a-dox1 was upregulated in roots of six week-old hydroponically grown ‘Flc’ plants following 24 hr exposure of 1 and 5 mM H2O2 treatments, However, upregulation in ‘AC’ plants was observed only at 5 mM H2O2 level. In the last experiment,   was upregulated by wounding and salt (after 6 and 24 hr exposure) treatments as well as 1 and 5 mM H2O2 (after 24 hr exposure). The regulation of short length form of   (a-dox1 5') in the all above mentioned experiments was the same as a-dox1  but, with much lower level upregulation. This study confirmed a potential role for a-dox1  in protecting roots of tomato plants from different kinds of oxidative stresses.

Using interspesific hybrids as rootstocks in genus Prunus is of interest for rootstock breeding programs in the world in recent years. A research was carried out on 106 natural and artificial interspesific hybrids at Sahand Horticultural Research Station in years of 2002-2005. Evaluation and selection of progenies was conducted according to some individual traits that are very important for clonal rootstocks. Morphological characteristics studied and rooting ability were tested on the 7 selections by hard-wood and semi-hardwood cuttings that had been treated with indolebutyricacid (with doses 2000 and 1500 Mg l-1, respectively) in greenhouse and outdoor conditions based on RCB design with three replications in each method. HS314 and HS312 genotypes (peach × almond) and HS302 and HS304 (prune × apricot) had high vigor, very good climatic adaptation and high rooting ability (30-60%). HS408 (plum × apricot) and HS721 genotypes (prune × almond) had complete flowers but their pistils were very short and sterile. Although they had very good characteristics as a rootstocks but their rooting percentage were low.

Many studies carried out for increasing the level of product quality including color, flavor, TSS and acidity. The effects of cane girding and boron foliar spray on pH, TSS, acidity, TSS/acidity and boron content of petioles are investigated in this study. Girdling carried out at two times, at the beginning of flowering and the stage of verasion. Boron was applied at foliar spraying with 0, 1500, 3000 ppm of boric acid at one week to flowering. The highest rate of pH resulted from foliar spraying of boron and foliar spray boron + veraison girdling treatments, showed that foliar spray was more effective on pH and TSS. The greatest rate of TSS was at foliar spraying with 3000 ppm of boron. The highest TSS/acidity was attained at foliar spraying with 3000 ppm of boron. Foliar spray with 3000 ppm of boron + girdling at flowering treatment had the most effective on content of boron attained from petiole analysis.