نشریه علوم سبزی ها
سال سوم شماره 2 (پیاپی 6، پاییز و زمستان 1398)

In order to investigate the possibility of chilling resistance induction and reduce the chilling injury of cucumber seedlings, a factorial experimental based on completely randomized design with three replications was conducted in a greenhouse at Ilam University, Ilam Iran in 2018. The experimental factors were included concentrations of 0, 5, 10 and 15 mM gamma-aminobutric acid (GABA) and two methods of application including seed priming and foliar application at four true leaf stages. Treated plants were incubated at 3 °C for six nights and then investigated for different characteristics. Results showed that all GABA treatments reduced chilling injury in cucumber seedlings. Moreover, although there were no significant differences among the different GABA concentrations for most of the studied characteristics, seed priming was better than foliar application. The lowest chilling index, lipoxygenase activity and highest shoot fresh weight were observed in seed priming application of GABA but with no significant differences among GABA concentrations. The highest shoot dry weight (6.77 and 6.68 g.plant-1), chlorophyll index (20.57 and 21.07 mg.g-1 FW: leaf fresh weight), total protein (1.29 and 1.25 g.kg-1), proline (21.92 and 22.42 μmol.g-1 FW), catalase activity (115.67 and 126.9 U.g-1 FW) peroxidase (0.61 and 0.63 U.g-1 FW) and the lowest ion leakage (30.22 and 29.22 %), malondialdehyde (0.65 and 0.60 μmol.g-1 FW) and hydrogen peroxide (1.27 and 1.19 μmol.g-1 FW), were observed in seed priming application of 10 and 15 mM GABA concentrations, respectively. Therefore, seed priming application of 10 mM GABA is recommended for reducing the chilling injury in cucumber seedlings.

Inter and intra-specific crossing is a useful technique to introduce characteristics from wild plants to commercial cultivars of asparagus. In this research, Inter and intraspecific crosses between Iranian wild asparagus and European commercial asparagus was carried out at university of Cordoba (Spain) during 2015-2018. Specific allele for each parental species and accessions was detected with help of molecular markers. The genetic nature of hybrid plants was then confirmed by detecting of parental specific alleles in progeny. Thereafter, some of the most important morphological properties were evaluated in parental and progeny plants populations. Successful interspecific hybridization was obtained between Asparagus breslerianus and A. officinalis. Specific allele (1086 bp in length) was detected by TC6 primer in A. persicus. Morphological analysis showed that the highest coefficient of variation (CV %) was related to number of spear, main stem diameter, length of primary and secondary branches and number of cladode. The number of spear, number of secondary branch and number of cladode were higher in hybrids obtained by crossing between A. persicus × A. officinalis than parental plants. Diameter and height of main stem, number of primary branch, diameter and length of primary and secondary branches, width and length of spear scale, leaf diameter and internode length of primary and secondary branches played an important role to create morphological variability in parental and hybrid asparagus populations.

Eggplant (Solanum melongena L.) is one of the most important crops in tropical and subtropical areas. Study of variation among existing varieties is essential for development of new varieties. This study was conducted to investigate the quantitative characteristics and trait correlations in 14 eggplant genotypes. The cultivars and genotypes were grown in a randomized complete block design with three replications at research farm of Sari Agricultural Sciences and Natural Resources University during 2018. Various traits including plant height, fruit weight, number of fruits per plant, day to 50 % flowering, number of branches per plant, fruit length, fruit diameter and fruit yield were measured. The results showed that there were significant differences among the genotypes for all measured traits at 1 % probability level. According to the results of mean comparisons AVF1 was identified as the best genotype with high fruit yield per plant. The study of trait correlations revealed that fruit yield had a positive and significant correlation with fruit weight, number of fruit per plant, number of branches per plant and fruit length. Using the stepwise regression analysis number of fruits per plant and fruit weight were selected as the significant variable in the model. The biplot analysis based on the first two components showed that there is a suitable genetic diversity among the studied genotypes, which can be used in eggplant breeding programs. Also, according to the direct relationship between the number of fruits per plant and the weight of fruit with fruit yield, these two characteristics can be used as a selection indicator to improve yield in eggplant.

Salinity stress is one of the most constraints for agricultural production in arid and semi-arid regions. Thus, genetically improved tolerance bred cultivars tolerant to salinity are needed for the future. The identification and selection of salt-tolerant genotypes is the starting point for such breeding purposes. Therefore, nineteen onion cultivars were selected and tested in two salinity levels (0 and 100 mM NaCl) in a completely randomized design with three replications in a hydroponic culture environment. The experiment was conducted at Horticulture Department of the Agricultural Sciences and Natural Resources University of Khuzestan during 2016-2017. The results analysis of variance revealed significant differences among yield of cultivars in no salinity (Yp) and salinity stress (Ys) conditions indicating the presence of genetic variation among the cultivars. In addition, in order to assess the salinity tolerance of cultivars, various stress tolerance indices were calculated based on Yp and Ys. Thus, the Esfahan and Azarshahr cultivars were identified as the most salt-tolerant cultivars. Principal component analysis showed that 94.3 % of total variance is explained by the first two components. The cluster analysis based on salinity tolerance indices divided the cultivars into three groups. In overall, stress tolerance index, geometric mean productivity, harmonic mean and yield index can be introduced as the most desirable indices for screening salt tolerant cultivars.

Eryngo (Eryngium caucasicum Tratvu.)is an endemic plant used as a leafy herb that its seed germination behavior has not been well studied. Research on its domestication and propagation can enhance its maintenance and commercialization. Therefore, a laboratory experiment was carried out with eight constant temperatures ranging from 0-35 °C (0, 5, 10, 15, 20, 25, 30 and 35 °C with three replicates in a completely randomized design at Agriculture Faculty, Ferdowsi University of Mashhad, Iran in 2016. Two regression models, including Intersected Lines Model and Quadratic Polynomial Model were applied to germination data to evaluate cardinal temperatures and R2 value was used as criteria for comparison between the models. Results showed that seed germination occurred at temperature of 10-25 °C. Optimum germination uniformity was obtaned at temperature of 10 to 20 °C. The temperature of 15 °C with highst germination percentage (88.33 %), germination energy (92.5 %), time to 90 % germination and germination uniformity (7.17 day) was found as the optimum temperature for seed germination. Quadratic Polynomial Model was found as a better model to evaluate eryngo seed germination. The temperature of 0.85, 15.33 and 29.81 °C were respectively estimated as minimum, optimum and maximum temperatures for eryngo seed germination. It is concluded that the data can be used to predict germination of eryngo response to temperature and management of the plant in agriculture as a new leafy herb.

Increasing waste production and accumulation of agricultural products is one of the environmental problems in different parts of the world. One of the ways to consume agricultural waste is to use it as a growth media for mushroom and to convert waste into higher value-added crops. In this experiment, the effects of substrates of wheat straw, date palm leaf, sugar cane bagasse and supplementary treatments including soybean meal, rapeseed meal and chicken manure (2.5 % W: weight) on growth, yield ad some biochemical constituents of oyster mushroom, in the mushroom cultivation hall of the Educational and Research Station of Khuzestan University of Agricultural Sciences and Natural Resources during 2014 were investigated. The results showed that adding soybean meal to palm leaf and wheat straw substrates or adding poultry manure to palm leaf significantly increased the yield of oyster mushroom (6.39, 5.97 and 6.30 kg, respectively). The yield of oyster mushroom in sugarcane bagasse or supplementation was lower than that of wheat straw and palm leaf. Growth period in bagasse containing supplements was significantly longer than other treatments. Total protein was increased significantly after the rapeseed meal was added to all three substrates, but soybean meal only was able to increase protein content in bagasse substrate (22.95 %). The highest oil content in bagasse substrate was found in rapeseed meal (1.81 %), the highest soluble carbohydrates, total phenol content were measured in wheat straw+ rapeseed meal, bagasse+ soybean meal were shown 59.11 % and 706 micrograms per gram of dry weight, respectively. The biochemical efficiency of oyster mushroom was affected by planting time and the lowest biological efficiency was in the bagasse substrate. The results showed that adding supplement to wheat straw and palm leaves yield and quality characteristics of oyster mushrooms were better than bagasse and the growth period was shorter than bagasse.

Manganese is a microelement for plants and is not actually counted as a metal pollutant. Manganese toxicity in some agricultural soils due to its excessive regeneration leads to undesirable symptoms in plants. Silicon is well known as reducing stress and toxic effects of some elements. A hydroponic experiment was conducted to evaluate the effect of silicon and manganese on leave of lettuce (Lactuca sativa L. cv. Siahoo) in greenhouse of Agricultural Faculty of Maragheh, Iran in 2016. The experimental design was completely randomized factorial design with three replicates. The treatments were three level of manganese (0.5, 2.5 and 5 mg/l) from MnSO4 source and three level of silicon (0, 14 and 28 mg.L-1) from Sodium metasilicate source. The results showed that with increasing manganese concentration, the levels of malondialdehyde, catalase, ascorbate peroxidase and hydrogen peroxide increased and total protein and fresh weight and dry weight of plant decreased. The highest plant fresh and dry weight loss was observed in 5 mg.L-1 manganese. Sodium metasilicate significantly reduced the level of malondialdehyde and hydrogen peroxide and increased the activity of the enzyme catalase, ascorbate peroxidase, total protein, plant fresh and dry weight. In general, application of high concentrations of manganese in nutrient solution decreases the plant growth and yield, while silicon application reduce the toxic effects of manganese and enhances the plant yield.

In order to investigate the effects of organic and biological fertilizers on growth characteristics and nutrient content of spinach (Spinacea oleracea L.), two experiments carried out under organic farming conditions at Mohaghegh Ardabili University, Iran during 2013. In the first experiment, to determine the optimal levels of organic fertilizers, vermicompost, compost, washed and unwashed spent mushroom compost with the ratios of 10, 20, 30, 40 and 50 percent by volume and control media based on a complete randomized design with four replicates were used. The results showed that the highest vegetative growth parameters were obtained in plants grown in medium containing 30 % vermicompost, 10 % consumed mushroom compost and 10 % unwashed consumed mushroom compost. The second experiment was carried out in a factorial arrangement in a completely randomized design with four replications. At first, spinach seeds of P1, P10 and P19 strains of Pseudomonas putida and strains R69, R150 and R159 from Pseudomonas fluorescens (first factor levels) were inoculated. Subsequently, inoculated and uninoculated seeds were planted in optimum substrates consisted of volume ratio of 30 % vermicompost, and the washed and unwashed consumed mushroom compost each with a 10 % volume ratio (second factor levels). The results revealed that the effect of organic and biological fertilizers on growth indices and nutrient content of spinach was significantly different in compare to the control. The highest plant height, chlorophyll content, leaf area, leaf fresh weight, leaf dry weight, total dry weight and the highest amount of nitrogen, calcium and potassium were observed in plants inoculated with R150 strain of P. fluorescens and 30 % vermicompost in the planting bed. Application of non-leached mushroom compost residue, vermicompost and leached mushroom compost residue and plant growth promoting bacteria had significant effects on growth indices and nutrient content of spinach. Among different plant growth promoting bacteria, P. fluorescens R150 strain had more effect on the studied traits.

To study the effect of different irrigation levels and plant densities on yield, yield components and morphological traits of artichoke (Cynara scolymus L.), a field experiment was conducted at Sarabelle Agricultural Research Station in Ilam province, Iran, during 2014-2015. The experiment was conducted as a split plot in a randomized complete block design with three replications. The treatments were four irrigation levels including 25 %, 50 %, 75 % and 100 % (control) of the plant water requirement that assigned to the main plots and four plant densities of 10000, 20000, 30000 and 40000 per hectare that assigned to the sub plots. The results showed that the highest plant height (242 cm), 1000-seed weight (36 g), number of buds (10 per plant), lateral shoots (10 per plant), total shoot dry weight (20872 kg.ha-1) and grain yield (2781 kg.ha-1) were obtained under 100 % plant water requirements. The highest total plant height (228.2 cm), 1000-seed weight (37 g), total shoot dry weight (20306 kg.ha-1) and grain yield (2830 kg.ha-1) were obtained at 40000 plant.ha-1. The highest number of buds per plant (10) and number of lateral branches (12) were observed at the density of 10000 plants.ha-1. The highest oil yield (694 kg.ha-1) was obtained at 40000 plants.ha-1 and under 100 % of the plant water requirement. According to the results, the highest grain yield was obtained at 40000 plants.ha-1 and under 100 % of the plant water requirement, but even under severe water deficiency conditions, it had high ability to produce forage, seed, bud and shoot. Under severe drought conditions(25 % of the plant water requirement) more than 9.8 ton shoots dry matter, 1.7 ton grain yield and 0.7 ton oil seed per hectare were obtained.

In order to investigate the effects of seed priming by polyamines on germination and seedling growth charecteristic of okra (Abelmoschus esculentus L .Basenti) at different temperatures two laboratory experiments were conducted as factorial layout based on a completely randomized design with four replications in 2014. In the first experiment, treatments were consisted two times (12 and 24 hours) and seed priming with five concentrations of spermine and spermidine (0, 0.5, 1, 1.5 and 2 mM). To determine the optimal time for okra seeds priming. The optimal seeds priming was occurred at 12 hours for all concentrations of spermine and spermidine. There after, seed germination and seedling growth study of primed seeds were carried out at temperatures of 10, 15, 20 and 25 °C in the second. Results showed that both seed germination and seedling growth of okra decreased by decreasing of temperature. The highest seed germination was observed at 25 °C. In addition, seed priming by spermine and spermidine caused significant increase in all germination and seedling growth characteristics of okra at 25 °C. Seed priming at 0.5 and 1 mM concentrations of spermine and spermidine were more efficient to improve seed germination and seedling growth charactristics of okra under different temperatures.

To study the effect of humic acid on alleviating the deleterious effect of drought stress in tomato (Lycopersicum esculentum Mill.), a factorial experiment based on randomized complete block design with three replicates and nine treatments was conducted. The treatments were 100, 50 and 25 % of field capacity (FC) irrigation with three humic acid levels (0, 500 and 1000 mg.L-1). Drought stress caused decrease in chlorophyll content, fresh weight of shoot and root, dry weight of root and number of fruit per plant. Humic acid improved tissue relative water content, chlorophyll content and fresh and dry weight of shoot. Also, treatment with 50 percent FC and 1000 mg.L-1 humic acid improved chlorophyll and relative water content and fresh weight of shoots and roots. Similarly, treatment with 25 percent of FC and 500 mg.L-1 humic acid increased chlorophyll content, relative water content and fresh and dry weight of roots. The chlorophyll content, tissue relative water content and fresh weight of shoot and root increased 20, 40 and 38 percent, respectively in 25 % FC and 500 mg.L-1 humic acid. However, fruit numbers per plant, fresh and dry weight of fruit were not affected by the treatments significantly. In conclusion, 1000 mg.L-1 humic acid in moderate drought stress (50 % FC) with 500 mg.L-1 humic acid in high drought stress were effective to alleviate the adverse effect of drought stress.

In order to investigate the effects of selenium and nitrogen on some growth and biochemical characteristics of edible onion (Cultivar Yellow Isfahan), a factorial experiment was conducted base on randomized complete block design with three replications at Razi University in year 2017. In this experiment, the first factor includes the time of split of nitrogen fertilizer (based on soil test, which includes 500 kg urea per hectare) in six levels including control, total fertilization at the time of transplantation, half fertilization at the time of transplantation, third fertilization at the time of transplantation, half fertilization at the time of transplantation+ half fertilization at the time of bulb initiation, third fertilization at the time of transplantation+ third fertilization at the time of bulb initiation+ third fertilization at the time of bulb growth and three levels of selenium (0, 10 and 50 mg.L-1 sodium selenate). The highest yield (21.44 Kg.m-2), fresh weight (251.83 g.bulb-1), the bulb length (84.19 mm), bulb diameter (78.66 mm), total phenol (19.87 mg.g-1 FW: fresh weight), total phenol (19.87 mg.g-1 FW: fresh weight), total flavonoid (9.30 mg.g-1 FW: fresh weight) and antioxidant activity (11.44 %) of the onion bulb were observed with nitrogen application of in three stages (third fertilization recommended at the time of transplantation+ third fertilization at the time of bulb initiation+ third fertilization at the time of bulb growth). Selenium had a positive effect on yield, fresh weight, length and diameter of bulb and total flavonoid in onion. Therefore, use of sodium selenate along with nitrogen plays an important role in improvement the growth and physiological characteristics of onion such as bulb dry weight (84.73 g.bulb-1) and nitrogen use efficiency (1 Kg.mg-1 DW: dry weight). In conclusion, split application of of 500 kg.ha-1 urea at the time transplantation, bulb initiation and bulb formation equally one third in each stage, and 50 mg.L-1 sodium selenate can be recommended for onion production.