مجله علوم باغبانی ایران
سال چهلم شماره 1 (بهار 1388)

Garlic (Allium sativum. L) has been and is clonally propagated, because it does not produce seed under standard conditions. Knowledge of plant recourses genetic diversity can be a first and most important step in achieving breeding program purposes. Because of its high accuracy and reproducibility among different genetic diversity assessment techniques Amplified Fragment Length Polymorphism (AFLP) has its unique importance. To discriminate among closely related garlic clones AFLP was applied to Analyze the genetic relations among Iranian garlic clones. Thirty-seven clones collected from the main cultivation areas of Iran were analyzed to evaluate their genetic diversity. A total 330 unambiguous bands were obtained by five primer combinations of EcoRI+3 and MseI+3, of which, 231 demonstrated clear polymorphism, representing 69% of total bands. Dendrogram obtained from Unweighted Pair Group Method with Arithmetic Averaging (UPGMA) using the coefficient of Jacard clustered Iranian garlic clones in 8 main groups, then the AFLP results were compared with morphological analysis. Based on AFLP results there existed relative high similarities among groups (0.58- 1) even though some of the clones showed very high similarity (>0.95). Sixteen clones in the 1st and 5th group shared 100% of bands of each group indicating that they are likely duplicate ones. In general there were not any significant relationships detected between genetic diversity and geographical origins. Clones of different ecological climates were classified in one group and in some cases clones that had close origins were clustered with clones from other geographical areas. The potential use of AFLP could show not only the differentiation among species, but also between botanical varieties and well-defined ecotype groups. Finally it can be concluded that AFLP fingerprinting technique with discrimination of duplicate accessions in germplasm collection can decrease costs of conservation of plant material, especially in the case of garlic that is propagated by asexual reproduction. The results of AFLP were in broad agreement with the morphological classification.

To reduce peat while increasing the Water Holding Capacity (WHC) of casing soil in button mushroom production an experiment was conducted in 2006 with three hydrogel treatments of: T0= casing soil with no hydrogel, as control, T1= casing soil + 10% hydrogel (V/V), and T2= casing soil + 20% hydrogel (V/V) with three replicates in a completely randomized design. Results indicated that treatment 1 significantly increased the total yield as compared to other treatments. The lowest yield was obtained through T2 due to an eventual decrease of casing soil porosity. The results also indicated that hydrogel use treatments could increase grade one button mushrooms, while decreasing mushrooms of grade three. Because of the increase in total yield and dry matter content of mushrooms a 10%. Hydrogel, as additional supplement for the casing, is recommended.

Eight accessions of Thyme medicinal plant, belonging to Iranian endemic Thymus daënensis, T. eriocalyx, T. migricus and an unknown Thymus spp species, were tested for karyotypic analysis, using squash technique and 2% (w/v) aceto-orcein staining method. Chromosomal parameters examined were: short arm (S), long arm (L), total length of chromosome (TL), arm ratio (AR), r-value, total chromosome volume (TCV), relative length of chromosome (RL), form percentage of chromosome (F%), Difference range of relative length of chromosome (DRL), total form percentage of karyotype (TF%), symmetry index (S%), centromeric index (CI), total chromatin length (X), dispersion index (DI) and coefficient of variation (CV%). ANOVA showed significant differences between accessions for S, TL and TCV. Six accessions were distinguished as diploids and two as tetraploids. The mean length of chromosomes ranged between 0.88 and 1.07 µm. The most common karyotype formula (KF) was 30m (5 accessions), followed by 28m, 56m and 58m+2sm (1 accession of each). Karyotypes were mostly symmetrical, falling in the Stebbins 1A category, except for A8 accession which fell in category. The present study indicated intra- and inter-specific variations in Thyme accessions.

To evaluate morphological markers linked with drought stress resistance for screening almond genotypes in the breeding programs the effect of drought stress was studied on six nominated almond genotypes seedlings. The six pre-selected water stress mimposed almond genotypes included: homozygote sweet (Butte from University of California), heterozygote sweet (Shahrood12, Shahrood18, Shahrood21 and White) and homozygote Bitter (Bitter Genotype). Moisture treatments were: well irrigated plants (?s=-0.33 MPa) vs drought stressed ones (?s=-1.8 MPa). The factorial experiment was conducted based on a randomized complete block design (2 irrigation factors, 6 genotype factors) of 3 replications. Such morphological and physiological traits as: leaf RWC and water potential, stomatal size and density, leaf and root N content, chlorophyll fluorescence, leaf size, root and shoot dry weight (DW), were assessed. Results indicated that different genotypes show varied degrees of resistance to drought stress. Analysis of leaf morphological traits and water status in plants showed genotypes, different strategies in coping up with and compensating for the effect of drought. All genotypes preserved their leaves although, having produced smaller leaves. Leaf size, root or shoot DW, stomatal density and root or leaf nitrogen content were not correlated with drought resistance in the studied seedlings. Ratio of root DW to leaf area increased with drought in White cultivar, while (by considering chlorophyll fluorescence and water relations) this genotype was the most resistant to drought among the studied cultivars. Specific leaf area (SLA) and stomatal size being the lowest in Butte led to the conclusion that it was the least resistant to drought.

Some crops have been observed to posses effects of allelopathic type. It would be interesting and useful as well to study these plant's allelopathic effects on other crop plants, particularly in rotation and intercropping. So, in this study, the allelopathic potential of cucumber organ's extract on seedling growth of cucumber, eggplant, pepper, and tomato was evaluated using a randomized factorial experiment, in a hydroponic system under greenhouse conditions. In this research, the first variable was plant type (cucumber, eggplant, pepper, and tomato) while the second one cucumber organ type (leaf, root, or stem) extract. Alcoholic extracts (5% w/v) of leaf, root, and stem of cucumber were prepared. The extract's effects on plant growth indices namely: number of leaves and flowers, root and shoot length, root and shoot fresh weight, as well as root and shoot dry weight were investigated. Results showed that all cucumber organ extracts exert significant inhibiting effect on growth indices of all tested plants. Under the allelopathic effect of cucumber organ extracts, eggplant and cucumber faced the most respective reduction in growth, in comparison with other plants tested. Therefore, it becomes evident that cucumber exerts the most allelopathic effect on eggplant. Also, a considerable reduction of cucumber growth could be attributed to self-toxicity in cucumber. In comparison with other cucumber organ extracts, root extract has the most retarding effect on plant growth. So, can be said that it has the most allelopathic effect. This phenomenon could be attributed to an initial production of allelopath chemicals in roots.

Breeding of almond to attain self compatible cultivars is among the objectives followed in almond breeding. Early identification of self-compatible genotypes from self-incompatible ones is very important in saving of time and expenses. There are different methods of either classical or molecular nature to recognize self-compatibility in genotypes. In this study, PCR-based method with specific primers was employed to determine self-compatible genotypes. Almond self-incompatibility system is of a gametophytic type controlled by a single multi-allele locus, expressed as S-RNase in style. In this research work, two commercial cultivars of Ferragnes (s1s3) and Ferralise (s1s3) were reciprocally crossed with self-compatible cultivar of Tuono (s1sf). Progenies (s1sf and s3sf) were grown and selfed (Bagging method) when they entered the flowering stage. Seeds of new generation were made to germinate following stratification. Seedlings were then studied through simple and multiplex PCR. Results indicated that the ratio of self-compatible to self-incompatible progenies was as according to Mendelian rules (1:1). Therefore, PCR was recognized as a precise method for identification of self-compatible genotypes when they are still very young.

One of the problems encountering gerbera production is the decreasing flower quality and yield especially when grown in non-standard greenhouse coditions. In this research the effect of weekly humic acid (HA) (500 mg/L) spray was studied and compared with application of 2 solutions containing 3.5 and 7 meq/L of calcium along with the same concentration of HA on Gerbera jamesonii L. It was demonstrated that although HA spray did not increase the uptake of most nutrients yet it could improve the yield in comparison with the solution alone a pplications. Calcium uptake was higher in the treatment involving HA along with a higher Ca concentration. There was no significant difference observed in postharvest life and total protein content among treatments. HA spray could significantly improve cell membrane stability of petal parts and decrease the stress imposed by scape senescence. It was probably through the hormone-like action of HA that the postharvest life of flowers was improved.

To inspect the effect of methyl salicylate (MeSA) vapor on fruit shelf life quality in kiwifruit (Actinidia chinensis cv. Hayward) an experiment was carried out in Citrus Research Institute, Ramsar, Iran in 2006-2007. The experiment was based on a completely random design of three replications. The treatments consisted of MeSA at five rates (0, 8, 16, 24 and 32 µL/L) and storage time of five levels (every month of five month duration of shelf life during the whole period of the experiment. Assessed qualities included: Total Soluble Solids (TSS), Titrable Acidity (TA), vitamin C, pH, firmness of pulp, activity of Ascorbate peroxidase (APX) and fruit ethylene production. The results of the experiments revealed that treatment with 32 µL/L of MeSA had the greatest effect on delay of postharvest ripening of fruits. Fruits treated with 32 µL/L of MeSA had a slower trend in decrease of pulp firmness and vitamin C as well as a slower trend in increase of TSS, ethylene production, and APX activity during storage as compared to control. Fruit TA decreased during shelf life period but MeSA did not have a significant effect on this trait. The highest delay effect of MeSA application on decrease trend of pH was observed in the 24 µL/L of MeSA application treatment.

Post-harvest losses particularly due to fungal invasions, is a major factor in limiting the shelf life of many fruits and vegetables. In order to study the effects of essential oils of thyme (Thymus kotschyanus), basil (Ocimum basilicum) and rosemary (Rosmarinus officinalis) on control of grey mold (Botrytis cinerea) disease in pear, a series of in vitro and in vivo (during cold storage of pear fruits) experiments was conducted. The concentration of essential oils used were 0 (control), 100, 200, 300, 400 and 500? l/l of PDA and 0 (control), 100, 300 and 500? l/l for in vitro and in vivo experiments, respectively. The results of in vitro experiment showed that rosemary and thyme oils had the lowest and the highest inhibitory effects on the fungal growth. Rosemary oil had no inhibitory effect on the fungal growth even at 500? l/l of PDA, but thyme oil, at concentrations above 200? l/l of PDA, completely inhibited the fungal growth. The results of in vivo (cold storage of fruits) experiment showed that essential oil treatment had significant inhibiting effects on fungal growth. The number of infected fruits and disease severity were reduced in the treated fruits. With increase in the essential oil concentration, fungal growth was further reduced. The highest vs the lowest number of infected fruits and disease severity were observed in 0 (control) vs 500? l/l of essential oil treatment, respectively. Also the results of this study revealed that thyme and rosemary essential oils had the highest and the lowest reducing effects on the number of infected fruits and on grey mold severity, respectively.

Milkthistle (Silybum marianum L.) is a rangeland medicinal plant growing wild in different locations in Iran. In the present research work, the effect of N, P and K in their different proportions of N0P0K0, N100P100K50, N150P150K100 and N200P200K150 kgHa-1 as compared with control (no fertilizer application) on the plant's growth was put to test. Suc variables as plant height, no. of capituls, no. of capituls per plant, diameter of capitul, no. of seeds per capitul, one thousand seed weight, and seed yield were assessed in a randomized complete block design of 4 treatments of each in 3 replications. Results indicated that different proportions of NPK exert different significant effects on plant height, no. of seeds per capitul and on seed yield. The highest plant height (107.81 cm) was resulted from N200P200K150 treatment, the greatest no. of seeds per capitul (223.08) from N150P150K100 and the greatest yield (3.6 tons ha-1) was the result of the treatment N100P100K50. There was a decrease in total silymarin and silybin observed with increase in NPK application. Increase in NPK application caused increase in vegetative growth and decrease in silymarin and silybin. This is while non application of NPK (control) resulted in an increase of 20.57% silymarin as compared with the N200P200K150 treatment. Silybin content of silymarin was the highest in N150P150K100 treatment. This was while even though total silymarin in control was at the same level as in treatments N150P150K100 and N100P100K50, but silybin available in its silymarin was reduced to an even zero level. Therefore it is concluded that the most suitable NPK proportion as regards; seed yield, and silymarin and silybin contents in milkthistle, variety Budakalazi, and in the area of Peykan Shahr, Karaj, Tehran would be N100P100K50.