IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2002 | Volume:2 | Issue:3-4|Papers Count:8

Experiments were conducted to study in vitro propagation of sweet orange using 5mm long epicotyl explants. Explants were excised from in vitro seedlings and cultured on a basic MS medium supplemented with various concentrations of benzyladenine (BA) and naphthalene acetic acid (NAA). After 60 days, the regeneration of adventitious shoots was recorded. The maximum percentage of regeneration and maximum number of adventitious shoots were obtained in BA concentrations of 1 and 2 mg 1-1. Increasing BA concentration decreased the production of adventitious shoots. Concentrations of 0.5 and 1 mg -1 NAA had not a significant effect on regeneration and number of adventitious shoots. However in low concentrations of BA, NAA increased the length of adventitious shoots, and maximum length of adventitious shoots was obtained on media containing 1 mg 1-1 BA and 1 mg 1-1 NAA. For rooting, basal medium with half strength of MS salts plus 3% sucrose, 7.5 g1-1 agar and NAA or indolebutryic acid (IBA) was used. A five-second dip of basal ends of shoots in 1000 mg1-1 NAA or IBA solutions and transferring to half strength MS salts medium were also evaluated for rooting. The maximum percentage of rooting was obtained on IBA-containing media and NAA did not affect rooting. Addicting NAA to medium resulted in callus formation in basal cut ends of shoots. The maximum percentage of rooting and root number and length were obtained in 10 mg1-1IBA. Plantlets were transferred to pots containing a mixture of 50% soil and 50% sand, and were irrigated by one-eighth strength MS salt solution for 10 days and then gradually acclimized to natural environment.

In order to select the superior genotypes for improvement program or for direct production, the comparative studies were carried out on the morpho-biological characters on Persian walnut population, in Khalat-Pooshan Research Station, in Tabriz University, during two years (2000 and 2001). In this study 50 different characters were considered in relation with climatic condition for genotypes evaluation. The means of data for all characters were compared using Dancun' s Test and their morfo-biological characteristics relation were evaluated by cluster analysis, finally the superior genotypes were selected. According to the results the genotype No. 12 for fruit and kernel weight, genotype No. 13 for kernel yield, genotype No. 17 for late leafing and blooming characters, genotype No. 35 for long pistil effective pollination period and genotype. No.3 7 for long anthesis period and lateral bearing were selected. In addition, in this study, 4 homogame, 17 prothandre and 27 protogyne genotypes were identified.

To study the physiological and agronomic characteristics of 20 genotyps of onions for evaluation of genetic variability and correlation between traits, experiment was conducted in 1999 at the Research station of the College of Agriculture, Isfahan University of Technology. Results showed significant (P=0.01) differences among genotyps for all 12 measured traits. The quite large differences for most traits shows high genetic variability among landraces studied. Using 11 traits, based on Pseudo Hotelling's T2 test and cluster analysis, the genotyes were classified in four groups with different physiological and agronomic traits. Principal component analysis revealed three components which explained 85.64 percent of the total variation among characters. The first component was related to productivitiy and the second and third was related to bulb shape. Plot of first principal component against the second confirmed the results obtained by cluster analysis. Finally, application of the results in onion breeding is discussed.

Land application of sewage sludge is considered beneficial as an inexpensive nutrient source. However, high concentration of heavy metals in sewage sludge may contaminate soil, and human and animal food chains. The objective of this study was to evaluate the effect of sewage sludge on yield and uptake of heavy metals by spinach (Spinacia oleracea) and lettue (Lactuca sativa) in soils with different pH levels. The study was carried out in greenhouse using a factorial experiment design with a completely randomized layout, with three replications. The factors were: four levels of sewage sludge: 0 or control (S0), 50(S1), 100(S2), 200 (S3) t ha-1, and one level of inorganic fertilizer (250 kg ha-1 ammonium phosphate and 250 kg ha-1 urea), four soils and two plants (spinach and lettuce). The highest spinach and lettuce yields were obtained in S3 in Rasht soil and S2 in Lahijan and Isfahan soils and S1 in Langaroud soil. Sewage sludge significantly increased concentration of Fe, Zn, Cu, Pb, and Cd in plant roots and shoots, and the concentration of some of the metals in plants reached to toxic levels in Langaroud and Lahijan soils.

In order to determine the effects of different concentrations of indolebutyric acid, position and time of cutting of semihard wood cuttings of almond x peach hybrid, clone G.F. 677, an experiment was conducted in Khalat-Pooshan Research Station, in Tabriz University at 1991. This experiment was arranged in a split factorial using a randomized complete block design with 3 replications. Hormone treatment included 4 levels: 0, 100, 200 and 300 ppm, position of cuttings on the shoots at 3 levels: terminal, middle and basal, and time of cutting at 5 levels: from 6 July to 6 August with 15 days interval. Results showed that hormone treatments increased the percent of rooting (P<0.0 I), and highest rooting was obtained with 200 ppm IBA on 6 August (p<0.01). Three-way interaction of 200 ppm IBA x basal cuttings x cutting on 6 August were significant for rooting percent and number of root at 1% and 5% levels, respectively. Length of root with 200 ppm IBA and number of root on 6 July and 6 August were more than others (p<0.01). Effects of 200 ppm IBA x meddle cuttings x cutting on 6 July for length of roots was significant at the 1% level.

Vegetable crops generally receive excessive amounts of fertilizers, especially nitrogen fertilizers. Recent attention has been focused on the possibility of over fertilization with nitrogen, due to their effects on the human health. Many species are known to accumulate nitrate. The nitrate has no toxic effects on plants, but it will be converted to nitrite, injurious to human consuming the crops. The objective of this project was to investigate the effect of different nitrogen levels on yield and accumulation of NO3-N in the edible parts of spinach and parsley. Five different nitrogen levels of 0, 50, 100, 150 and 200 Kg N ha-1 were used in complete randomized blocks in 1998 for spinach. Nitrogen levels of 0,80, 160,240 and 320 Kg N ha-1 were also used in complete randomized blocks for parsley in 1999 in Khalat Pooshan research station in Tabriz University. The results showed that with increasing of nitrogen levels for spinach and parsley, the yield was increased. Also, application of nitrogen fertilizer had significant effects on nitrate accumulation in spinach and parsley. Considering the accumulation of nitrate, there were remarkable differences among leaf blades, petiols and stems in both vegetables. Nitrate concentration in leaf blades was lower than petiols and stems. The average of nitate concentration in different nitrogen levels in leaf blades of spinach was 0.524% D.W. and in parsley was 0.21% D.W. In order to have an acceptable yield and a low concentration of nitrate in these two vegetables, it is recommended to use 50 Kg N ha-1 for spinach and 80 Kg N ha-1 for parsley, in different areas of vegetable crops production in Tabriz.

To study the applicable ways for increasing the quality of melon crop in Isfahan, different combinations of irrigation systems (surface, trickle and porous pipe) and polyethylene covers (transparent, black and no polyethylene mulch (control) were used. The study was carried out as a split-plot experiment in a randomized complete block design (irrigation systems as main plot and soil covers as subplot) with three replications. During growth period, cultural practices were done and fruits were sampled in three stages in order to measure the total soluble solids (TSS), water content, and dry matter and also plant vegetative growth. Results showed that irrigation systems and soil covers (P=5%) have significant effect on recorded characteristics. Trickle and porous pipe irrigation systems caused at least 1% increase in TSS. In prous-pipe irrigation system, water seepage caused plant vegetative growth and fruit yield to reduce, due to poor quality of the pipes. The best treatment with high water use efficiency was trickle irrigation system. The effect of different polyethylene mulches on TSS was equal. The highest and lowest rates of TSS were 6.65% for porous pip irrigation with clear mulch and 4.19% for surface irrigation without mulch, respectively. Leaf area and length of plant and fresh-weight were higher in surface irrigation with polyethylene mulches.