مجله علوم باغبانی ایران
سال چهل و چهارم شماره 2 (تابستان 1392)

This reasearch was conducted to study the phenotypic diversity of Thymus kotschyanus populations. Seeds were collected from natural inhabitats (Guilan، Mazandaran، West Azarbaijan، Semnan and Qazvin) and planted in Qom reasearch station in 2007. A number of some such different morphological and phenological traits of the plants as plant،s height، leaf length، leaf width، oil content، internode length، diameter of inflorescence and flowering stage as well as full bloom were evaluated. Analysis of Variance revealed significant differences among populations in all the studied traits except for the cases of peduncle length and diameter of inflorescence. Results of simple correlation analysis revealed the existence of significant correlations among some of the plant،s important characterstics. One of the most conspicuous traits of the plant، namely oil content was in significant positive correlation with the number of flowers per inflorescence and with internode length while being in negative correlation with fresh weight، leaf length as well as leaf width. Factor analysis was also carried out for defining of the determinant factors and the traits constituting each factor. A number of 5 main and indipendent factors explained over 82. 9% of the total variation related to the main effective characterstics. Populations of the plant were separated into six groups as by cluster analysis and through Ward method. Populations of Mazandaran 2 contained the most oil content (2. 5%) as well as the number of flowers per inflorescence، two highly desirable traits to be employed in the plant،s breeding programs.

To evaluate the effect of different levels of drought stress on some physiological parameters in strawberry، potted experiment involing strawberry cultivars ‘Marak٫، ‘Camarosa٫ and ‘Gaviota٫ was conducted during summer 2009. The experiment consisted of three drought stress levels in three replications. The experimental arrangement was a factorial one، based upon a randomized complete block design. Such physiological parameters as leaf Relative Water Content (RWC)، Membrane Stability Index (MSI)، net photosynthesis (A)، stomatal conductance (gs)، transpiration (E) and chlorophyl content were assessed in leaves of strawberry subjected to different drought stress conditions. The recovery of these parameters was also studied after the plants started to be rewatered. It was shown that RWC، MSI، A، gs، E، and chlorophyll content decreased with soil water content being reduced. ‘Gaviota٫ cultivar bore a lower gs and transpiration rate than ‘Marak٫ and ‘Camarosa٫. Recovery of these parameters occurred soon in all the cultivars. Chlorophyll content in ‘Gaviota٫ was higher than those in ‘Marak٫ and ‘Camarosa٫ under different treatments with Chlorophyll recovery not taking place till one day past of the start of rewatering. Level of Prolin increased slowly in all the cultivars as drought stress increased. Level of prolin in ‘Gaviota٫ was higher than those of the other cultivars، but one day past of rewatering، the level of prolin was sharply reduced.

Effect of five hybrid cucurbita (Cucurbita maxima×C. moschata cvs.) namely: Azman-RZ، Ferro-RZ، ES152، ES101 and RS841 as rootstock and two grafting methods (splice and hole Insertion) on the survival rate، some vegetative growth traits and as well on quantitative and qualitative traits in greenhouse grown cucumber، cv. «Khassib» was investigated in greenhouse conditions. The survival rate differed among rootstocks and between grafting methods with ES101 as rootstock and hole insertion، as grafting method exhibiting higher early survival rates. Length of main stem at 30 Days After Planting (DAP)، length and number of internodes، early and final yields as well as rate of marketable fruits were affected by different grafting methods. The kind of rootstock significantly affected the length of main stem at 30 DAP، number and length of internodes، early، middle and end period of harvesting as well as total yield، length to diameter ratio of fruit and rate of marketable fruits (p< 0. 05). For most of the investigated traits، the grafted plants benefited from a better status than non-grafted ones، but not all the rootstocks showed similar effects، so can''t be presented as rootstocks for many cultivars. According to the obtained results RS841 was the superior rootstock for cucumber cv. «Khassib».

The effect of Ca، Zn and B spray application on preharvest fruit drop، sugars، calcium، zinc، and boron concentrations and as well on some physicochemical fruit properties of five commercial Asian pear cultivars (‘KS’7، ‘KS’8، ‘KS’11، ‘KS’12 and ‘KS’14) was investigated under Tehran Province،s environmental conditions. Trees were sprayed one month past fruit set until harvest within two week intervals with Ca، Zn، B and as well with their mixtures at 5% concentrations. Fruit drops were recorded from treatments، start untill harvest. At the time of fruit harvest، fruit sugar and mineral contents were determined using HPLC and ICP، respectively. Results revealed that Ca، Zn and B applications decreased preharvest fruit drop in a way that a combination of Ca، Zn، and B applications rendered a 6. 3% fruit drop in comparison with 17. 3% occurring in control. Throughout the research، fructose was found out as the dominant sugar followed by glucose، sorbitol and sucrose in the studied cultivars. Spray applications of Ca، Zn and B increased the fruits، fructose، glucose، sorbitol and sucrose contents in all the studied cultivars (1-2. 5، 1-2. 1، 2-3. 7 and 0. 7-2. 2 % fresh weight، respectively). In addition، total soluble solids increased by 1-2 ºBrix total sugars (1-2 % of fresh weight)، total acidity (0. 07-0. 12 mg 100-1g) and dry weight (1-1. 5g) of fruits in all cultivars. Spray of Ca increased fruit firmness (1-2 N varied with cultivar). Spray of Ca، Zn and B applications increased Ca، Zn and B mineral contents of both leaves and fruit.

In order to prevent the shrinkage of olive fruit and maintain its fresh being، and also to increase the oil content and dry matter، the effect of kaolin at three levels of application (0، 2. 5% and 5%) on four varieties of olive (Mission، Conservolea، Keillet، Blady) was evaluated within a period of four months، in Ahwaz، the tests being repated in 3 replicates. Results revealed significant effects of kaolin on fruit size، flesh/stone (wet weight)، flesh/ stone (dry weight) and oil contentof the fruit. Kaolin did not significantly affect oil content in wet matter. The highest fruit size، flesh/ stone (dry weight) belonged to 2. 5% kaolin while the lowest was related to control. Highest vs. lowest wet weights of flesh/ stone were attributed to 5% kaolin vs. control، respectively. In contrast، a maximum of oil content went to control، while a minimum belonging to 2. 5% treatment.

The following study was conducted at the Research Station of Horticultural Sciences (University of Tehran، Karaj) to investigate the effect of different irrigation levels and fruit site on the stalk upon the traits of: sink-source relationship، yield، and fruit quality in two Iranian melon cultivars. The statistical design was a split split-plot of three replications. Treatments consisted of a factorial arrangement of three irrigation levels (starting irrigation at -50، -65 and -75 cbar)، four thinning levels (retainment of fruit at the second، fourth or seventh node of each of two secondary stems vs. control plants undergoing no thinning) along with two cultivars of Iranian melons (Zard Jalali and Suski Sabz). Results revealed that water stress reduced fruit weight as well as yield. The lowest fruit weight and yield were obtained in the case of severe stress treatment (-75 cb). Thinning methods exerted significant effects on mean fruit weight and yield. The highest values having been obtained from fruits kept on the 7th node treatments. The cultivar “Zare Jalali” bore higher fruit dry matter (%) and benefited from a higher flesh firmness as compared with “Suski Sabz”. The first water stress treatment increased Total Soluble Solids (TSS) content. Retainment of fruits on the 7th node resulted in the highest level of TSS (10. 77%). Water stress resulted in a significant shortening of the ripening time for about 7 days. Retainment of fruit on the 2th node caused earlier ripening of the fruit. Water stress reduced photoassimilate production and improved fruit sweetness. Also، water stress and thinning affected fruit ripening.

Apricot (Armeniaca vulgaris L.) is a popular and an economically profitable fruit of the temperate zone. Various apricot genotypes grow in different areas in Iran. The genetic diversity of 30 cultivars and genotypes of Iranian apricot and as well، of two foreign cultivars (as control) was studied through morphological attributes and RAPD markers. In a first experiment، 21 quantitative and qualitative characteristics regarding the fruits، leaves، trees as well as flowers were evaluated. Results of simple correlation analysis revealed the existence of significant، positive vs. negative correlations among some important traits. In a second experiment RAPD markers، through an application of 35 decamer primers، were used for genetic diversity analysis of the apricot cultivars. Bands of acceptable resolution and high repeatability were picked out to be used in calculations. A cophenetic coefficient of r=0. 79 was found out between similarity matrices. Grouping of cultivars through cluster analysis was highly varied. The study demonstrated RAPD markers as a useful technique for studying the genetic diversity as regards apricot cultivars and genotypes. As a whole، the results indicated that there exists a high level of polymorphism among cultivars and genotypes in Iranian apricot indicating that Iran could be one of the main origins of diversity of the apricot throughout the world.

Grapevine rootstocks are of the potential to increase cultivars، adaptation to different climates، soil types and a variety of unfavorable conditions. Considering the existence of a rich grapevine germplasm in Iran، it is possible to pick up vigorous genotypes and cultivars as drought tolerant rootstocks for commercial use due to their vast genetic potential. In this study، 698 fruitful genotypes from the collection of the National Iranian Grapes Research Station، Takestan (Qazvin province) were studied as based upon the characters considered in the grapes، descriptor with emphasis on vigor grape، descriptor related traits and some potent genotypes being selected within three distinct stages. The first stage of evaluation، that included leaf and branches، hair density traits، resulted in choosing 150 genotypes، further evaluated for trunk diameter and shoot length in three replications as the second stage. A third stage of evaluation was comprised of 17 morphological traits associated with drought tolerance، studied on the screened genotypes in field conditions at the National Collection of Grape Varieties of Iran. The final number of genotypes was decreased to 44، within medium screening، and with consideration of others، recognized drought tolerant genotypes. Results indicated that there was not any correlation between trunk diameter and shoot length، and therefore shoot length could not be considered as an index of vigor and its related drought tolerance. There were significant positive vs. negative correlations between and among the studied traits، except for shoot length. Kaj Angur of Bojnurd، Sorkhak from Quchan، Siyah Mamuli (Ordinary Black) of Zarghan and Ghalati of Shiraz bore drought tolerance traits and were proposed as promising، but only after، undergoing further complementary experiments.

In order to investigate the effect of different levels of cycosel and naphthalene acetic acid on some vegetative traits and on essential oil yield from rose-scented geranium (Pelargonium graveolens Heritier)، an experiment was conducted in 2008 in the research greenhouse of Horticulture Department of Zanjan University. The study was arranged as a factorial experiment، based upon a randomized complete block design of three replications. The first factor included different levels of naphthalene acetic acid (0، 40، 80 and 120 ml) while the second involving cycosel (0، 500، 1000 and 2000 ml). Analysis of variance of the data showed the effect of naphthalene acetic acid was significant as regards all the factors except plant dry yield. The effect of cycosel acid was significant on all the factors too. Furthermore، interaction between cycosel and naphthalene acetic acid was significant regarding all the factors too. Mean comparison of، and relations between characters indicated that application of suitable concentrations of cycosel as a plant growth retardant along with naphthalene acetic acid as a growth promoter was effective on increasing traits essential oil yield (mlplant-1)، percentage (ml100gr -1) related with herb production of plant، dry matter yield per plant and leaf/stem fresh weight ratio. The most increace in more characters obtained in plant that was treated by suitable concentration of cycosel such as 500 and 1000 mlL and naphtalen acetic acid with 40 ml، which were most effective on balanced increasing of essential oil yield and herbage yield in Geranium.

Alstroemeria is a cut-flower that has recently become increasingly popular because of its beautiful flowers of various colors، and high yield. Leaf yellowing is considered as a primary index of Alstroemeria flower deterioration. In order to study how to alleviate this disorder and improve the flower،s longevity as well as its other quality traits، a factorial experiment was conducted on the «Napoli» cultivar of Alstroemeria cut-flowers. Throughout the experiment، different levels of ethanol (0، 2، 4، 6%) and of GA3 (0، 50، 100، 150 mg/liter) along with 4% sucrose، were applied in preservative solutions in either one of the two forms of pulse or continuous application. The evaluated traits were: flower longevity، chlorophyl content، flower fresh weight، solution uptake، relative water content، flower diameter، as well as ion leakage. Based on the obtained results، the most leaf chlorophyll content was found in cut-flowers treated with 100 mg/L GA3 in either one of the pulse or continuous methods. But، the continuous method proved to have better effects on flower vase life، solution uptake، flower fresh weight and as well on the diameter. Also، application of 2% ethanol along with either 100 or 150 mg/L of GA3 was found out to bring about the most increased flower longevity. Application of higher concentrations of ethanol in this treatment caused a decrease in the flower vase life.