IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2009 | Volume:10 | Issue:1|Papers Count:7

This research was conducted to evaluate the effect of root zone temperature (RZT) on calcium concentration and leaf necrosis of lily 'Navona' in three different seasons during 2006 and 2007. Bulbs with 16-18 cm in circumference as plant material and cocopeat and perlite mix as medium used in experiments. Traits such as incidence and severity of leaf necrosis and mineral concentration of leaves were analyzed. Results indicated that with incrementing the RZT from 9 to 20 °C, calcium uptake and mean Ca concentration of leaves significantly increased. In second experiment, that Ca concentration of leaves was 0.55% DM, leaf necrosis was not occurred. In the first and third experiments, mean Ca concentration of leaves were 0.22%, and Ca concentrations of middle leaves (the most sensitive part to necrosis) were 0.11 and 0.13%, respectively. Calcium concentration of necrosed area in damaged leaves, were 0.09 %. Also reduction in light intensity and increment of relative humidity in second experiment, did not significant effect on calcium concentration and thus leaf necrosis did not occurred. On whole results revealed that low RZT was the main reason of incidence and development of leaf necrosis in lily 'Navona'.

This study was conducted to determine physiological respons of Lolium perenne L. 'Bartwingo' and Poa pratensis L. 'Barimpala' to salinity and ammonium: nitrate ratio during germination and early seedling growth. The five salinity levels (0, 20, 40, 60 and 80 milimolar sodium chloride) were applied in half strength Coic nutrient solution containing 6 meq I-1 nitrate and 4 ammonium levels (0, 0.25, 0.5 and 1 meq I-1). In generals salinity reduced germination percentage and rate, shoot and root length and shoot chlorophyll content in both species. Shoot proline and malondialdehyde content increased as salinity levels increased. Regardless of salinity, effects of ammonium levels were not considerable, but interaction between salinity and ammonium concentrations showed that in both species, at higher salt concentrations, increasing ammonium concentrations reduced germination rate, shoot and root length and shoot chlorophyll and increased proline and malondialdehyde, Whereas in nonsaline nutrient solution or in low salinity levels there was no significant difference among ammonium levels and in some parameters result was opposite with those in higher salinity. These data suggest that, feeding these two turfgrass cultivars with mixture of nitrate and ammonium (according to Coic nutrient solution) result in the best growth, but in high salinity medium, ammonium levels must be reduced as salinity increases.

The effects of N supply, growing medium and transplanting time on the photosynthesis, growth and macronutrients level of two olive (Olea europaea L.) cultivars ('Arbiquina' and 'Roughani') Were studied. In two propagation times (spring and autumn), the rooted plants were grown in plastic pots containing perlite: sand (1: 1) or soil: sand: organic matter (1: 1: 1) mixtures and were irrigated with different amounts and forms of nitrogen for 9 months. The result of this study indicated that olive can use both the nitrate and ammonium forms of N. However, high level of nitrogen, especially ammonium form, is deleterious to the photosynthesis and growth of olive nursery plants, therefore, depended on olive cultivars, addition of small amounts of NH4 to N03 solution (12 meq lit-1), increases of the photosynthesis and growth (4, 6 meq lit-1 NH4). for 'Arbiquina' and 'Roughani', respectively. Addition of NH4 to nutrient solutiond influences not only the rate of growth but also the absorption of other ions. Absorption of NH4 by plants, as compared to N03, decreases K and increases N and P uptake. The mean effect of the cultivar on the organs concentration of nutrients was significant and high N and P and high K use efficiency was seeing in 'Arbiquina' and 'Roughani' cultivars, respectively. On the other hand, olive growth and photosynthesis affected by growing media and transplanting time, so that, the soil media and spring time were the best for these purposes.

Assessment of genetic relationships of plant populations and selecting of suitable parents for hybridization and production of new cultivars is highly important. In this study, genetic diversity of 15 olive cultivars from different origin (Iran, Spain, Syria, United States. and Greece) were evaluated using AFLP markers. A total of 695 bands were produced using nine primer combinations in which 675 (97%) bands were polymorphic. The maximum and minimum number of bands were produced by P2 and M21 and P2 and M24 with 101 and 64 bands, respectively. Comparing of correlation coefficients showed that the best similarity coefficient for clustering is simple matching coefficient with coefenetic coefficient of 92%. Dendrogram classified the genotypes in three main groups and most of the Iranian cultivars were clustered in one group. High similarity was observed among most of the Iranian and Spanish cultivars. It seems that the Iranian and Spanish cultivars have the similar origin.

Self -incompatibility is one of the major problems in almond commercial cultivars. To solve that, many breeding programs have been conducted. In this research, late blooming, self- compatible cultivar of 'G-2-25' (S11Sf) as a female parent was crossed with self- incompatible cultivars of 'Desmayo Largueta' (S1S25) and 'Marcona' (S11S12) both as male parents. Progenies were evaluated for their S- allele genotype by fluorescent microscopy, analyzing of stylar ribonucleases by NEpHGE and PCR methods. The results showed that all different methods including fluorescent microscopy, NEpHGE and PCR, could differentiate self- compatible from self- incompatible genotypes and their results confirmed each other. The ratio of S- allele genotypes in population obtained from crossing of 'Marcona' and 'G-2-25' was according to expected mendelian ratio. However, in crossing between 'Desmayo Largueta' and 'G-2-25', only genotypes of S1S11 (21%), S1Sf (53%) and S25Sf (26%) were obtained and there was no S11S25 genotype among progenies. This situation may be related to lethal gene effects, or certain reciprocal effect among S- alleles.

Considering growth pattern and ecological factors are two important aspects in the orchard management system. This research was conducted in order to determine fruit and vegetative growth patterns of 9 Asian pear cultivars grown under the Research and Collection Orchard, Department of Horticulture Science at Tarbiat Modares University during 2006 and 2007 growing seasons. At the first year (2006), 45 mature trees (9 cultivars in 5 replications) and at the second year (2007) 90 trees of Asian pears were selected for the experiment. The assessments were carried out from 57 days after full bloom (DAFB) at the 7 and 10 days intervals during the first and second years of the experiment until the fruit harvest. The obtained data was used to analyse and compute the cumulative and absolute vegetative and fruit growth pattern. Also the meteorological information of the experimental site was obtained for two years from the nearest meteorological station 1 km from the experiment Results indicated the existence of a simple and completed fruit sigmoid curve for all studied cultivars. The onset of different stages of the cumulative growth curve was different among the studied cultivars. According to the results, 'KS7', 'KS10', 'KS11' and 'KS14' are early maturing: 'KS6', 'KS9', 'KS13' are mid season, and 'KS8' and 'KS12' are late maturing fruit cultivars. The simultaneous monitoring of vegetative and fruit growth pattern in the cultivars is one of the main objective and strength of the present research. This is a possibility for using the obtained results for the management of Asian pear orchards under Tehran environmental condition.

In June bearing strawberries, short day is necessary to induce flowering and produce one crop per growing season. On the other hand, growth regulators with similar effects of short- days on flower initiation may improve out of season production and increase yield in strawberries. In this study, the effects of short days (SD), various rates of paclobutrazol (0.2, 0.4 and 0.6 mg active ingredient per plant) (PBZ) at non- inductive day lengths and their combinations (SD+PBZ) on vegetative and reproductive growth of 'Camarosa' cultivar (a June bearing strawberry) were investigated. In general, applying of PBZ in long days increased leaf chlorophyll contents, plant dry weight, number of leaves, petiole thickness and root dry weight compared with SD treatment. The results also indicated that the application of PBZ at the rate of 0.6 mg per plant led to 216.67, 180, and 206 % increase in flower numbers, fruit numbers and yield, respectively, when compared with SD treatment. However, this treatment reduced leaf area and petiole length. SD+PBZ treatments had no significant effect on number of flower and fruits per plant in comparison to SD treatment. The PBZ application had no significant effect on fruit firmness, total soluble solids and vitamin C.