Background and Objectives: The objective of haploid plant production is to obtain doubled haploid (DH) lines universally suited to breeding programs. Crop productivity can be greatly improved by using F1 hybrids, which are made by crossing pure lines with some important traits. These pure lines are very valuable in breeding programs and genetic researches. Production of pure lines in a conventional breeding program via self-fertilization takes a long time and requires high costs, but still may not be 100% homozygous. Alternative biotechnological approaches are by far more efficient and sustainable than traditional methods. The most common and best-known method of obtaining haploid cucurbit plants is via pollination with irradiated pollen, which induces parthenogenetic development of haploid embryos in plants. According to the previous reports, there has not been consensus for superiority of gamma ray doses between 300 and 500 Gy; however these two doses have not been simultaneously compared in any research study published so far. The aim of this study was to investigate the possibility of haploid embryos induction in different cucumber cultivars through pollination with gamma-irradiated pollen and determine the optimal dose of irradiation for cucumber haploid plants production. Materials and Methods: In this study the effects of irradiation doses and maternal genotypes on fruit set, seed production, parthenogenetic embryo induction were investigated after pollination by irradiated pollen and production of haploid plants in cucumber. This research study was performed in a factorial experiment with two factors (gamma irradiation dose and plant genotype) based on a completely randomized design (CRD) with 6 replications. Seven cucumber genotypes including, Extreme F1, Negin F1, Karim F1, Super Dominus F1, Beith Alpha OP, Basmenj and Dasgerdi were pollinated with gamma-rays irradiated pollen grains at doses including 300 and 500 Gy. The pollen viability and pollen tube behavior after irradiation were evaluated. The seeds extracted from the fruits were rescued by in vitro embryo culture, and the ploidy level of the plantlets obtained was determined by flow cytometry. Results: The impact of different doses of gamma irradiation, genotype, and interaction of dose and genotype on total number of seeds produced were significant. The highest number of parthenogenic embryo were observed in genotype Extreme irradiated with dose of 300 Gy (2. 25) and genotype Karim irradiated with dose of 500 Gy (1. 75). No embryo and plant was obtained in genotypes Negin, Extreme and Beith Alpha irradiated with the dose of 500 Gy. The difference of various doses of irradiation on production of haploid plants was not significant, but genotype and especially interaction effect of dose and genotype were significant on production of haploid plants. Pollination of genotype Extreme by 300 Gy – irradiated pollen grains gave rise to the highest number of haploids (1. 25Hs/fruit) produced in this experiment. Conclusion: In this research study similar to previous studies, it was confirmed that production of haploid plants using irradiated pollen grains is an efficient method for producing haploid inbred lines in cucumber. According to our results, different genotypes exhibited different responses to various doses applied and parthenogenic embryogenesis can be induced when optimal dose of irradiation was applied in each genotype.

In recent years, disposal of waste tires is an environmental challenge in many countries. Previous researches has been shown that rubber waste ash and its nanoparticles can be used as an effective source of zinc (Zn) for plant. In this research, feasibility of using nanoparticles and rubber waste (as zinc supplying source in plant) is studied moreover comparing the nanoparticles of rubber waste with commercial zinc sulfate fertilizer available in the market. In this regard, moreover nanoparticles production and characterization them by scanning and transient electron microscope, these wastes were used in cucumber hydroponic culture, then the quantitative and qualitative performance of the fed products were compared with the commercial zinc sulfate fertilizer available in the market. According to the obtained results, by reducing the particle size of the rubber from micron to nano, Zn extractable percentageincreased from 1. 5 to 2. 5%. So, using rubber nanoparticles increased plant performance and also, increased Zn concentration in plant tissues compared with commercial zinc sulfate fertilizer and those grown in control.

This experimental was conducted to investigate the efficiency of polyethylene mulches and suitable sowing method on row, for cucumber in field in Isfahan during 2000 and 2001. Cultivar of cucumber was Super dominos hybrid. Statistical design was split plot on randomized complete block with four replications. Soil cover in three levels (black mulch, transparent mulch and without mulch) were considered as the main plot and sowing method in two levels (single and double rows) as sub plot. Field management and data collection from different treatments were done during growth period. Results showed that transparent polyethylene mulch had a positive effect on early germination of seeds and precocity production. Yield in transparent, black and non mulch treatments were 57.5, 40.2 and 33.6 (tha-1), respectively. Maximum plant vegetative growth and minimum weed were obtained from black polyethylene mulch treatment. Polyethylene mulches had a favorite effect on soil moisture maintenance in bed. Maximum yield was obtained in double row sowing method, but single row sowing increased the marketability of fruits, length and weight of plants.

Cucumber is a warm season crop that suffers from chilling injury at temperatures below 10OC. In recent years, jasmonates have been used for reduction of chilling injuries in plants. An experiment was, therefore, conducted to test whether methyl jasmonate (MeJA) application at various concentrations (0, 0.05, 0.1 and 0.15 mM) through seed soaking or foliar spray would protect cucumber seedlings, subjected to chilling stress. Results showed that MeJA application decreased chilling index, ion leakage, malondialdehyde content and hydrogen peroxide free radical and increased growth parameters, proline contents, chlorophylls contents and antioxidant activity. Although, seed soaking method provided better protection compared to foliar spray method, the highest cold tolerance was obtained with 0.15mM MeJA application in both application methods that caused low level of chilling index (1.67), malondialdehyde content (0.11 nm g-1 FW), hydrogen peroxide free radical (0.22 nm g-1 FW) and ion leakage (32.87%). In general, it may be concluded that MeJA could be used effectively to protect cucumber seedling from damaging effects of chilling stress at the early stages of growth.

Cucumber is one of the important agricultural products consumed in various forms by people in Iran and other places in the world. One of the important factors in reducing the production of this product is soil and water salinity. The aim of the present research was to investigate the effects of salinity (NaCl) on vegetative and physiological characteristics of cucumber (CUCUMIS SATIVUS L. ). In this experiment, after growth of plantlet, (after weeks), they were exposed to different concentrations of sodium chloride solution including, , , and mM were treated and irrigated. Samples were taken after applying all salinity concentrations to different plant rows. Then characteristics such as the number and length of the root, the number of leaves, the weights of fresh and dry root and shoot, relative chlorophyll and chlorophyll fluorescence were measured. The results of data analysis showed that different salinity concentrations reduced vegetative and physiological characteristics of the cucumber. The highest quality of vegetative characteristics was observed in control plants and, with increasing the salinity concentration, the vegetative characteristics decreased until the lowest quality was observed in all mM salinity treatments. The highest amount of potassium in shoot and root was observed in control plants and then mM NaCl treatment, and the lowest amount was observed in mM NaCl. The highest levels of root and shoot Na were observed in and mM NaCl, respectively. Salinity caused the reduction of chlorophyll in the plant and in conclusion some of plants due to reduction of chlorophyle level induced chlorosis and finally were dead. This problem was observed in plants with higher salt concentrations.

In an attempt to investigate the effect of osmopriming on seed germination characteristics of cucumber (CUCUMIS SATIVUS L.), a factorial experiment in a completely randomized design with 3 replications was conducted in laboratory. Treatments included: PEG with 5 and 10% concentrations, KNO3 with 1 and 2% concentrations, and KCL with 2 and 4% concentrations and the seed soaking times were 6, 12, and 18 hours. The results indicated that the maximum radicle and shoot lengths were respectively found under KCl 4% and PEG 5% priming treatments and 12-hour time period. The maximum R/S length ratio, R/S dry weight ratio, and R/S fresh weight ratio were respectively obtained from KNO3 1 and 2% priming treatments in 6- and 18-hour periods. The highest and the least radicle, shoot, and total dry weights were respectively obtained from PEG 5% and KNO3 2% treatments in 6- and 18-hour time periods. The highest germination percentage and germination rate belonged to the priming under KCl 2 and PEG 2 and 5% treatments during 6- and 12-hour periods. Therefore, seed priming with KCl better enhances seed germination and seedling growth in comparison to the other solutions.

Effect of different amounts of nitrogenous fertilizer as Urea (0, 50, 100, 150, 200 and 250 kg N/ha) was studied on growth, yield and nitrate accumulation in cucumber cv. Daminos. The experimental design was a complete randomized block with four replications. Several plant and fruit characteristics consisting of number of male and female flowers, lengh and weight of plants, number and weight of fruits, dry matter percentage of fruits and plant and eventually yield of first and second grade fruits were recorded. Nitrate amout in fruits as measured for every harvest of morning and afternoon. Results showed that the number of female flowers increased with increasing the level of nitrogen. This increment was correlated positively with the increment of plant length. Nitrogen application at levels of 150-250 kg/h showed significantly higher total yield compared to that lower levels. Nitrate amount in fruit tissue was increased with increasing level of applied nitrogen and reached its highest level with application of 250 kg/h nitrogen. The level of nitrate was always higher in fruits harvested in the morning compared to those harvested in the afternoon. The level of nitrate reached its toxicity threshold in treatments of 200 and 250 kg/h nitrogen when harvested in the moning but for afternoon harvest it reached toxicity threshold when 250 kg/h nitrogen was applied. It can be concluded that nitrogen can be applied at 200 kg/h if it is supposed to be harvested in the afternoon but only 150 kg/h nitrogen can be recommended if it is supposed to harvest in the morning.

The compatibility studies of Pseudomonas fluorescens (Pf1) with azoxystrobin at different concentrations viz., 100, 150, 200, 250 and 300 ppm revealed that it was compatible with all the concentrations of azoxystrobin tested and the growth of the bacterium was unaffected even at the maximum concentration of 300 ppm. The field experiment revealed a foliar application of Pf1 (2.5 kg ha-1) and azoxystrobin (250 ml ha-1) combined, reduced downy mildew as well as powdery mildew disease severities more than azoxystrobin (250 and 500 ml ha-1) alone. An application of Pf1+azoxystrobin treatment recorded only 2.22 and 1.00 Percent Disease Index (PDI) of downy mildew and 1.85 and 0.50 PDI of powdery mildew during the first and second seasons, respectively. The treatment also recorded a maximum fruit yield of 14.30 and 15.65 tonnes ha-1 for the first and second seasons, respectively. Application of Pf1 along with azoxystrobin significantly increased the survival of Pf1 in the phylloplane of cucumber crop. In addition, there was multifold increase in peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, b-1, 3 glucanase, chitinase and phenolics in plants treated with Pf1+azoxystrobin.

One of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops is low temperature. Hydrogen sulfide (H2S) is an important signaling molecule involved in several stress-resistance processes such as drought, salinity and heavy metal stresses in plants. The aim of this study was to investigate the effects of exogenous H2S on improving chilling tolerance of cucumber seedlings. The results indicated that seedlings exposed to chilling stress (4 º C) increased the level of electrolyte leakage, lipid peroxidation, hydrogen peroxide, proline content and guaiacol peroxidase (GPX) activity; while sugar soluble content decreased. Pretreatment with sodium hydrosulfide (NaHS), a hydrogen sulfide donor, slightly reduced the malondialdehyde content, hydrogen peroxide content and electrolyte leakage, which were induced by chilling stress and also elevated the activity of antioxidant enzymes, soluble sugar and proline levels, and reduced glutathione content in plants under chilling stress condition. Pre-treatment with other Na+ and sulfur-containing components including Na2S, Na2SO4, Na2SO3 showed no significant effect on lipid peroxidation and hydrogen peroxide content under chilling stress. It can be concluded that the effect of NaHS pretreatment on alleviation of cold stress damages is probably related to its ability to release H2S because Na+-or sulfur-containing compounds (except NaHS) had no similar effects on alleviation of chilling damages.

The scarcity of water, along with the concern of safe production of food, emphasizes the need for new agricultural techniques. Increasing dissolved oxygen concentration in water promotes the growth of plants in many ways. The aim of the present research was to investigate how cucumbers (CUCUMIS SATIVUS L. ) morphologically and physiologically respond to water enriched with air Micro-NanoBubbles (MNBs) as an oxygen saturating measure. The plants from early stage of seed planting (two groups, 32 plants in each) were cultured either with air-nanobubbles water or with tap water for 12 weeks, and the steric stability of MNBs in water was confirmed through zeta potential measurements (-20. 47 mV). The number of blossoms in the plants irrigated by air MNBs water was almost 3. 8 times more than the number of blossoms in those that were irrigated by tap water. MNBs water increased leaf area up to an average of 77%. Physiological indices such as chlorophylls a, b, and carotenoids were, respectively, 1. 34, 1. 44, and 1. 35 times greater in the plants watered with MNBs than those with tap water. Overall, this study demonstrated that water with air micro-nanobubble had a positive effect on cucumber plants and is potentially an effective tool for the environmental friendly, economical, and profitable production of the plant.