Iranian Journal of Horticultural Science
Year:2012 | Volume:43 | Issue:1|Papers Count:10

Embryogenic Callus initiation from anther and whole flower explants in four grapevine cultivars including Flame Seedless, Shahroodi, Perlette and Red Sultanina cultured on PIV and Harst nutrient media was studied. Results showed that whole flower explants of ‘Flame Seedless’ cultured on PIV medium had the most potential for callus production. Later callus were transferred onto GES1CA medium for embryogenesis. In the latter medium, ‘Shahroodi’ expressed the highest rate of embryogenic callus production as compared with the other three cultivars. Meanwhile, only the anther explants showed the potential for producing embryogenic callus.

Damage caused by freezing can be the result of differences in cellular processes, including changes in membrane properties, interactions between macromolecular and enzymatic reactions. In this experiment, Total Soluble solids (TSS) and relative water content of the reproductive buds of cultivars “J. H. Hale”, “Elberta,” “Redhaven,” “Sorkh Sefid Mashhad” and “Amsden” peaches, along with nectarines: “Independence”, “Kuota”, “Stargold” and “Nectard no:6”, were evaluated in the months October, November, January, February and March 2009 under natural conditions. Extent of orchard electrolyte leakage, the level of LT50 (i.e. the temperature killing 50 percent of the sample) and total soluble sugar of the cultivars were assessed under controlled conditions in February 2009. Results showed that in February and under natural conditions, the total soluble sugars of peach and nectarine cultivars, in February were more than those at the other times and the relative water content in all the peach and nectarine cultivars increased with approaching the time of bud opening in March. In controlled conditions, by reduction of temperature, amount of electrolyte leakage intensified while the total soluble sugars decreased. Also, the level of resistance in peaches and nectarine cultivars varied, so that “Sorkh Sefid Mashhad”, “Redhaven” and “Amsden” peach cultivars as well as “Starglod” and “Nectared 6”, nectarine cultivars had the highest resistance to winter freezing conditions in the month of February.

This experiment was designed and conducted to increase to yield as well as quality of greenhouse cut-rose. The experiment was conducted in a factorial arrangement, based upon a completely randomized design of three replications, under hydroponic conditions. The study was followed with the aim of investigating the effects of cultivar type (‘Bull's Eye’-‘Cherry Brandy’), pot volume (5-8L) and canopy management method (bending-pruning). The experimental work was performed for a period of six months in a greenhouse located in north-east of Tehran. Based on the results, ‘cv. Bull's Eye’ showed preference over Cherry Brandy’ only with regard to production rate, but some qualitative traits which relate to flower, causing satisfaction of customers and promoting marketing, were more pronounced in ‘cv. Cherry Brandy’. Effect of pot volume was significant on flowering stem count as well on fresh and dry weights of roots; in a way that better results were obtained in 8L substrate volume. Bending resulted in yield reduction as compared with pruning, but with a consideration of the rest of the traits, bending method resulted in positive and significant effects.

Kiwifruit softening and the spread of gray mold on the fruit are the most important factors to be considered in Kiwifruit storage life. In this study, the effect of calcium chloride (0, 1, 2, 4 and 8 percent) for 2, 4 and 8 minutes of dipping time were examined to improve the fruit physicochemical characteristics. Following fruits being dried (24 hours), they were stored at 0.5oC and 85-90% RH for 18 weeks. Samples were taken at 6th, 12th and 18th weeks and subsequently measured in some triats including water loss, firmness, TSS, TA, TSS/TA, pH, L* and a* values of color indices and ascorbic acid in comparison with control. Results showed that the fruits immersed in 4 and 8 percent of CaCl2 solution for 4 and 8 minutes had the highest firmness (3.4 kg). Water loss in control fruits was recorded higher (0.3 kg) than in all CaCl2 treatments. PH and TA parameters did not show significant changes during storage. Due to decrease in TSS through CaCl2 application, there occurred a significant difference in TSS/TA ratio. A positive relationship was observed between the L* value (47 value) and firmness especially when 2, 4 and 8 percent of CaCl2 were applied. In general, ascorbic acid increased in both control and CaCl2 treated samples but it was recorded higher in control during storage. In conclusion, CaCl2 treatments increased fruit quality and storage life due to inhibition of TSS increase and continuous firmness.

Genetic diversity of 36 genotypes of dwarf and semi-dwarf apple rootstocks along with seven Iranian dwarf rootstocks were investigated by use of RAPD DNA markers. A set of 100 random primers was utilized in PCR reaction from which 10 primers resulted in good amplification with high polymorphism. Among primers, 10 selected RAPD primers produced 160 bands, in which, 136 were polymorphic. Cluster analysis was done based on polymorphic bands using Dice similarity coefficient and UPGMA method. The highest genetic similarity (90%) was detected between B9a and B9b samples. Grouping of dwarf apple rootstocks showed the most proper correlation with their sampling area, showing either close genetic background or existence of the same parents. In cluster analysis, four distinct groups of 0.6 similarities were identified. Cophenetic coefficient between similarity matrices and dendrogram was 0.89, showing a proper fit of dendrogram with similarity matrices. This experiment showed RAPD markers as a suitable and efficient technique to differentiate apple Dwarf rootstock samples.

A principal obstacle facing intensive pear orchard establishment in Iran is the absence of appropriate dwarfing or semi-dwarfing rootstocks, compatible with commercial cultivars, as well as showing adaptability with alkaline soils. This research aimed at an evaluation of the hawthorn seedlings (Crataegus sp.) as a potential dwarfing rootstock for pear and a comparison of its dwarfing effects with clonal quince A and normal pear seedling rootstocks on several commercial and fire blight tolerant pears (2005-2010). The evaluated cultivars were Spadona, Dar Gazi and Harrow Sweet, beside two moderately fire blight susceptible cultivars namely Bartlett and Shah Miveh. Results confirmed high dwarfing effects of Crataegus and semi-dwarfing of quince A rootstocks on pear cultivars. Reduced tree size on dwarfing rootstocks resulted from decrease in the tree height and its canopy expansion ended up to reduced tree vigor, but the rootstock type did not affect the length of the internodes. None of scion/rootstock combinations demonstrated incompatibility-dependent disorders including abnormal scion/rootstock growth rate. With respect to the low growth induced in the shoots of pear cultivars on Crataegus rootstock, and difficulties in transplanting of this rootstock due to its weak root productivity, it seems that this species does not possess the potential to be used as an efficient dwarfing rootstock for commercial pear cultivars.

Calla lily, an ornamental bulbous plant from Araceae family (consisting of seven species) is characterized by spadix inflorescence and utilized for cut flower as well as for pot plant. A greenhouse study was conducted in university college of Agriculture and Nature Resources of Tehran University, to evaluate the quantitative and qualitative characteristics of pot plant of Calla lily. The type of design was a completely randomized design of factorial arrangement and three replications. Experimental factors included preplant treatment with three levels of gibberellic acid (0, 100, 200 ppm) and three levels of benzyl adenine hormone (0, 100, 200 ppm) as well as two levels of storage temperature (10oc, 20oc) and two levels of rhizome storage duration (4 & 8 weeks). The results indicated that effect of duration of preplanting storage of rhizomes was significant on the number of days from planting to emergence. Also, storage temperature exerted a significant effect on this trait at 1% level. A temperature of 10ºC delayed the number of days from planting to emergence. According to significant four way interaction, maximum shoot number (7.67 shoots per rhizome) was obtained when 4 weeks of storage temperature of 20oC × gibberellin solution at (200ppm) × benzyladenin solution at 200ppm were applied. However, a minimum of shoot number (1 shoot for every rhizome) was observed when 8 weeks of storage × temperature of 10oC × dipping rhizomes in distillated water × foliar spraying with distillated water were employed. A comparison of means in evaluation of interaction effects of four factors indicate that plants which are related to treatment number 16, had the highest leaf area. This treatment was related to plants the rhizomes of which were dipped (during preplanting) in 200 ppm gibberellin solution and were stored for four weeks in a temperature of 20oC with their foliage being sprayed by distillated water. Meamwhile, application of gibberellin caused the increase in rhizome diameter (at the end of experiment) to be less than that in control treatment. So, maximum increase in rhizome diameter was observed in control treatment.

This experiment was carried out in the Agricultural Faculty of Guilan University. The Factorial experiment was performed based on a completely randomized design of three replications. The experimental factors comprised of: lillium cultivars, Navona (Asiatic) and Fangio (LA), four levels of calcium nitrate (0, 1, 1.5 and 2 mM) in combination with three levels of IBA (500, 750 and 1000 ppm). The results indicated that calcium content, significantly affected all sections of the plants at the level of 5% (a=%5) except for the adventitious roots in crown. The longest vase life, wet and dry weights of plants as well as leaf area were observed at 2 mM calcium nitrate level treatment. The most adventitious roots per plants were observed in 1000 ppm of IBA treatment. The lowest leaf necrosis, ethylene production in flower, floret drop and cell leakage of leaf, stem and flower observed at the 2 mM calcium nitrate and at 1000 ppm IBA. However, interaction of calcium nitrate and varieties indicated that threshold of good nutrition in the two varieties varies. Overall, it is indicated that, the best growth in Navona and Fangio occur in 1.5 and 2 mM of calcium nitrate application, respectively. The results finally showed that one of the methods of decreasing leaf necrosis while increasing vase life in lily cut flower is the use of calcium nitrate, accompanied with somehow promotion of adventitious roots.

As regards the kind of use and production of biomass, lettuce benefits from a potential of acting as a bioreactor in producing recombinant proteins as well as edible vaccines. For the propose, one needs to optimize tissue culture and gene transformation in Lactuca sativa. Seeds of two cultivars TN-96-39 and TN-96-41 were disinfected in a solution of 2.5% sodium hypochlorite containing 0.1% Tween 20 for 25 minutes. This was followed by three rinses of sterile distilled water. The seeds were then germinated in Petri dishes on filter paper soaked with sterile distilled water. The cultures were continuously exposed to white fluorescent light at a constant temperature of 25oC, for a minimum of 16 hours. When aseptically germinated seedlings were 48 to 72 hours old, cotyledons were excised near the cotiledonary node, and cut into either 6 or 8 pieces to expand the already existing wound on the explants for callus growth. The most suitable growth regulators for callus production and embryogenesis were 0.05 mg/l NAA, and 0.2 mg/l BA. The most appropriate growth regulator for direct regeneration and proliferation was found out as 0.05 mg/l NAA, 0.4 mg/l BA. To produce roots, shoots were transferred to MS medium culturing 0.2 mg/l of NAA. Strong root bearing plantlets were planted in pots to produce seeds. Transgenic plants of lettuce cultivars (TN-96-39, TN-96-41) were produced by use of Agrobacterium tumefaciens vectors containing the b- glucuronidase (GUS) reporter gene and the nptII gene for kanamycin resistance as a selectable marker. High frequency of transformation based on kanamycin resistance and GUS expression, was obtained with 72-h-old cotyledon explants cocultivated for 48 h with Agrobacterium tumefaciens strain LBA4404 & 2 minute dive for infection at cultivar TN-96-39. Progenies of T0 and T1 plants along with PCR & assay demonstrated linked monogenic segregation for kanamycin resistance and for GUS activity.

Grape vine is one of the important horticultural crops with unique standing as regards use and consumption. The fruit is utilized from immature to ripened state and as raisins. Its leaves can be used when they are soft and fresh. Therefore it is necessary to improve Iranian grapevine quality as well as quantity. The main purpose of this study was the use of Phenyl Phetalamic Acid (PPA) to increase fruit set and fruit quality. The experiment arranged in factorial design, included four cultivars (Razeghi, Askari, Sefidali and Rish baba) along with three concentrations of PPA (0, 500, 1000 mg/Lit) as based on a completely randomized design of three replications in Kashmar vineyards (Khorasan Razavi province) in spring 2010. PPA was sprayed at 50% flowering stage. Analysis of variance indicted that using PPA exerted significant effects on cluster (weight, length and number), and on berry (number, weight, length and diameter). The most fruit set index (berry number per cluster) was observed in Sefidali with 263.11 berries per cluster. Askari, Razghi and Rish baba with 113, 109.89 and 76.11 respectively, stood as the next ones. Askari and Razeghi showed similar and insignificant differences towards the reaction while their differences were significant from Rish baba. Results revealed interaction effects to be significant for cluster, berry and seed traits while insignificant for number of berries per cluster. Based on the results, cluster characteristics were affected by 1000 mg/L of PPA significantly. It could positively affect the fruit set and increased it by 26.2% compared with control (except for Askari). The most effective treatment for berry characteristics was 500 mg/L of PPA that showed insignificant differences with the 1000mg/L of treatment. Finally PPA as an auxin synergist showed positive effects on grapevine fruit set, probably with a decrease in apical dominance of terminal buds and diverting metabolites to clusters, resulted in improvement of berries characteristics.