JOURNAL OF CROPS IMPROVEMENT (JOURNAL OF AGRICULTURE)
Year:2018 | Volume:20 | Issue:3 |Papers Count:12

The current research has been conducted to investigate the effects of different seed coating treatments on seed germination of canolaunder drought and salinity stresses. For so doing, it has conducted two factorial experiments, based on completely randomized designwith four replications in the central laboratory of Aburaihan Campus, University of Tehran. In both experiments, one of the factors hasincluded 10 different seed coating treatments (T1-T10), varying in terms of seed priming type, the kind of coat, and employedfungicide. The second factor has been different for both experiments. The first experiment investigates the levels of drought stress, viz. 0,-0. 8,-1, and-1. 2 MPa, while the second one deals with the levels of salinity stress, viz. 0, 7, 14, and 21 ds/m NaCl. Results indicatethat the lowest hydrotime constant (θ H) belongs to T9 (22. 627 MPa h), T3 (22. 538 MPa h), and T6 (22. 263 MPa h), with the lowestbase water potential (Ψ b (50)) observed in T4 (-1. 332 MPa) and T1 (-1. 324 MPa) and the maximum germination percentage undersalinity stress (Gmax) showing up in T2 (86. 75%). Furthermore, the highest threshold to salinity tolerance (Xo) belongs to T3 (16. 38ds/m) and the highest germination rate to T3 in all levels of salinity. Totally, seed coating treatments of T3, T6, and, T9 have been thebest treatments under drought stress with T3 being the best treatment under salinity stress. Also, investigation of relations among theparameters of hydrotime model and salinity model indicates that by decreasing the hydrotime constant, the threshold of salinitytolerance will be increased and more negative values of base water potentials result in higher values of maximum germination insalinity. What is more, seed priming with humic acid improves germination rate and can increase the threshold of salinity and droughttolerances. As a result, seed producers are recommended to use seed priming with humic acid prior to any seed coating treatment.

In order to evaluate the increment possibility of bean seed yield by application of brassinosteroid, the present study has conducted asplit factorial experiment, based on randomized complete block design with three replications. The experiment has been carriedout in the research farm of Agriculture Faculty, the University of Zanjan, during cropping seasons of 2016-2017 and the irrigationlevels include optimal irrigation with drought stress applied to main plots and bean cultivars (Kusha cultivar and COS16 genotype). Four levels of brassinosteroid, namely no-application (control), two, four, and six μ M have been allocated to subplots as factorial. Drought stress has been applied in the flowering stage, wherein the bean plants have been simultaneously sprayed with bothbrassinosteroid (epibrassinolide) and drought stress. Results show that drought stress decreases leaf area index, yield components, seedyield, biological yield, and harvest index and the application of epibrassinolide minimizes the negative effects of drought stress, increasing the above traits. The highest seed yield belongs to the application of two μ M of epibrassinolide with an average o f 2068. 2kg. ha-1. Also, among the studied cultivars, the Kusha cultivar under optimal irrigation with an average of 3025. 45 kg. ha-1 shows higherseed yield, compared to COS16 genotype. Therefore, the use of epibrassinolide can be suggested as a solution to increase drought stressresistance and enhance seed yield of bean under optimal irrigation and drought stress conditions.

In order to evaluate the effect of smoke-water and urea fertilizer on some growth indices, grain yield, and yield components of wheat, the present study has carried out a field experiment as a split-plot, based on randomized complete block design with three replications. The experiment has been conducted in Razi University Research Station, Iran, during the cropping season of 2015-2016, and theexperimental treatments include different levels of urea fertilizer application (90, 180, 300, and 360 kg ha-1) as the main factors and leaffoliar application with different concentrations of smoke-water (0%, 0. 001%, 0. 01%, 0. 1%, and 1% v/v) as the sub-factors. Resultsshow that smoke-water significantly improves all studied traits, increasing wheat grain yield, compared with the control treatment in allurea fertilizer levels. The highest grain yield (922 g. m-2) belongs to the application of 350 kg ha-1 urea and smoke-water at theconcentration of 1% v/v, while the lowest one (339 g. m-2) is related to the application of 90 kg ha-1 urea and foliar with distilled water. The grain yield has been improved by 15. 22%, 11. 36%, 7. 18%, and 7. 67% from the application of 90, 180, 300, and 360 kg ha-1 urea, respectively, in 1% concentration of smoke-water, compared to the control treatment. It seems that smoke-water application improvesthe growth indices and yields of wheat by both increasing nitrogen efficiency and reducing the yield loss.

The present study conducts an experiment in order to investigate the effect of terminal drought stress on agronomic and qualitativetraits of canola genotypes in the application of ammonium sulfate condition. Carried out during two periods of 2015-2016 and 2016-2017, the experiment entails a factorial split-plot design, based on completely randomized block design with three replicates, and hastaken place in the research farm of the Seed and Plant Improvement Institute (SPII). In the pod formation stage, irrigation factorsinclude two levels, namely, normal and restricted, while for the elongation stage of ammonium sulfate, the two levels are 0 and 150 kgper hectare, both set in the main plots as factorial with cultivars including BAL111, BAL119, BAL121, BAL128, and Nima, set in thesubplots. Results show that among the examined genotypes, line BAL128 has had the highest grain yield (3904 kg/ha), which hasincreased by 28%, compared with the control treatment. The highest amount of grain oil (45. 53%) has been obtained in the second yearof experiment and under normal irrigation conditions. By applying ammonium sulfate, the amount of oil has increased by 2. 5% incomparison with normal condition. The BAL128 line has had the highest percentage of grain oil (44. 29%). In normal irrigationcondition, the use of ammonium sulfate reduces the amount of glucosinolate by 22. 88%; however, in restricted irrigation condition, theamount of glucosinolate declines by 17. 25%. In the irrigation and fertilizer treatments of this experiment, among the lines studied, theBAL128 line is recommended for similar experimental conditions.

In order to study the effect of Nitrogen rate and plant density on grain yield as well as the efficiency of Nitrogen use in blessed thistle, afield study has been carried out as a randomized complete block design with factorial arrangement of the treatments in three iterationsduring the growing seasons of 2013 and 2014, at Research Field of Tarbiat Modares University. The treatments have been comprised offour pure Nitrogen rates (viz. 0, 50, 100, and 150 kg N ha-1) from urea sources and five plant densities (namely 5, 10, 15, 20, and 25plants m-2). The main effects of nitrogen and plant density have proven to be significant for grain yield, NUE, plant height, SPADvalue, root to shoot weight ratio, and Nitrogen content of the grain. It has been found that higher Nitrogen rates leads to greater grainyield, SPAD value, plant height, and grain Nitrogen, though it results in lower agronomic efficiency as well as Nitrogen recovery andutilization. What is more, higher densities result in decreased grain yield and chlorophyll index, while improving NUE throughoutincrement of root to shoot weight ratio and plant height. All in all, the novel findings of this study could be used for the management ofNitrogen.

In order to investigate the impacts of irrigation cutting and chemical and biological fertilizers, Azoto Barvar 1 and phosphate Barvar 2on grain yield, essential oil, and biochemical properties of cumin, an experiment has been conducted as split plot, based on arandomized complete block design with three replications in the University of Zabol Research Farm during 2016. Main factors includefour levels of irrigation cutting, namely conventional irrigation, irrigation cutting between stem elongation to flowering stages, irrigation cutting between flowering stage and the beginning of the grain filling period, and irrigation cutting from the beginning to theend of the grain filling period. The sub-factor is the different type of phosphorous fertilizer, including control (no fertilizer application), Azoto Barvar 1 and Phosphate Barvar 2, and triple superphosphate. Results indicate that the interaction of irrigation cutting andphosphorous fertilizer has been significant on seed yield, oil percentage, carbohydrates, proline, total protein, absorption of nitrogen, phosphorous, and potassium. The greatest seed yield, oil percentage, total protein, nitrogen, potassium, and phosphorus has beenobtained from conventional irrigation along with the application of Azoto Barvar 1, while the greatest proline has been achieved fromirrigation cutting between beginnings to the end of grain filling period along with the application of triple superphosphate. The greatestcarbohydrate has been observed from irrigation cutting from the beginning to the end of the grain filling period along with theapplication of Phosphate Barvar 2. In conclusion, results indicate that biofertilizers have positive impacts on the improvement ofnutritional conditions of plants under irrigation cutting conditions.

The present study aims at investigating the morpho-physiological responses of purslane plant to methyl jasmonate under salinity stress. As such it has conducted a split plot experiment, based on a completely-randomized design with two factors and three replications, inMedicinal Plants Research Center, Shahed University, Tehran, in 2017. The factors include salinity with four levels (0, 3, 6, and 9dS/m) as main factors and methyl jasmonate with four levels (0, 0. 25, 0. 5, and 0. 75 mM), the latter regarded as a sub-factor. Resultsshow that by increasing salinity levels, the growth indices such as root length, fresh weight of root, chlorophyll b, total chlorophyll, andthe amount of superoxide dismutase decline, while by increasing the salinity levels, the proline content and the activity of catalase andMDA in the leaf rise. Applying methyl jasmonate under salinity stress reduces not only the growth indices but also the photosyntheticpigments. The highest number of branches, number of leaves, and chlorophyll b have been obtained at a salinity of 6 dS/m with 0. 5 mMmethyl jasmonate. By raising methyl jasmonate level, the proline content and the activity of CAT increases, while the amount of MDAand SOD enzymes decreases. Therefore, it can be concluded that the tolerance of Portulaca oleracea plant to salinity is up to 6 dS/m, and that the consumption of low amounts of methyl jasmonate can improve yield and physiological indices in purslane.

The present study attempts to find the most suitable planting time and place as well as the best variety of Brompton stock for cultivationin the spring. As such, it conducts an experiment as split-split-plot arranged, based on randomized complete block design with threereplications in Shahid Bahonar University's greenhouse, Kerman, during 2016-2017. The treatments include planting date (fifth ofSeptember, October, November, December, and January) as the main factors, planting sites (inside/outside the greenhouse) as the subfactor, and the variety (two red and white ecotypes along with two cultivars of Cinderella Pink and Cinderella Violet) as sub-subfactors. The significant difference of planting time could be seen in the plant's height, number of days for budding and flowering, floretand inflorescence diameter, number of florets per plant, fresh weight of the floret and the plant, itself, and vase life of flowers. This, however, cannot be detected in inflorescence height. The planting site has had significant influence on all traits, except plant height, inflorescence height, and leaf number per plant. Results show that the delay in planting has decreased the number of days for buddingand flowering in all varieties, cultivated in both planting sites. The growth period of local varieties has been significantly longer thanthe breeding varieties. Moreover, planting outside the greenhouse has had more appropriate conditions in terms of temperature thaninside. In general, planting the local red variety on 5 October and outside greenhouse conditions is the most suitable treatment forsupplying the Brompton stock to the New Year market in the beginning of spring.

In order to determine the best time and amount of Glycine Betaine (GB) for increasing tomato yield under drought stress condition, anexperiment has been carried out as split plots, based on RCBD design with four replications, during 2016 growing season. Theexperimental factors include the main factors (irrigation period in 6 and 12 days) as well as the sub-factors, namely the time (in 3 levelsof sowing, flowering, and fruit set) and the amount (in 3 levels of 0, 3, and 6 kgha-1) of GB application. Results from RWC, leaf area, and electrolyte leakage show the efficiency of GB application under stress condition. The use of GB in non-stress condition leads todecreased fruit weight with no significant difference observed between 3 and 6 kgha-1 dosages. In stress condition, application of 3kgha-1 GB in the sowing, flowering, and fruit set stage has increased fruit weight by 33%, 40%, and 60%, respectively, compared to theaverage fruit weight in control treatments. Although the positives effect of 3 kgha-1 GB in the flowering time on fruit yield has beenobvious (i. e., 62% higher) in this study, it seems that the application of this amino acid at the non-stress conditions has had some toxiceffects on tomato fruit yield.

Regulated deficit irrigation and subsurface irrigation lead to increased high water use efficiency and water saving. As such, the presentstudy conducts a field factorial experiment, based on randomized complete block design with three replications in Agricultural andNatural Resources Research and Education Center, southern Kerman, during 2014-2016. It evaluates two factors, namely deficitirrigation (100% ETc in total growing stages, 60-100% and 80% ETc, with the exception of flowering and fruit-filling stages) andirrigation method (deep subsurface, subsurface drip, and surface drip irrigation). Vegetative traits, yield, and water use efficiency havebeen measured during the growing period of sweet orange (Citrus sinensis var. Mars Early) grafted on Citrus aurantium with the resultsshowing that the regulated deficit irrigation practices save water by about 17%, compared to complete irrigation. It also reducesvegetative growth, even though there has been no statistically significant difference in the yield. Furthermore, subsurface irrigationsaves water by about 10%, compared to surface drip irrigation, improving at the same time vegetative growth and water use efficiency. Therefore, it can be concluded that regulated deficit irrigation and subsurface irrigation are very effective for improving the water useefficiency and water saving.

The limited water resources of Iran renders modern methods of water conservation and preservation, e. g. the use of superabsorbentpolymers in the soil, one of the confront approaches of water deficit. As such, in order to investigate the effect of superabsorbent onvegetative and reproductive growth of Page Mandarin in drought stress condition, the present study has conducted a factorialexperiment, based on completely-randomized design, with three replications in the Citrus and Subtropical Fruits Research Center ofRamsar during 2016. The factors are consisted of three levels of water stress (100%, 75%, and 50% of field capacity) andsuperabsorbent (0%, 0. 25%, and 0. 5% wt). Results show that by increasing water stress, amounts of electrolyte leakage, proline, fruitcracking, and titratable acidity have increased. Also, at the 50% of field capacity level, 0. 5% superabsorbent application has caused asignificant increase in leaf relative water content, total chlorophyll content, leaf water potential by 60%, 15%, 23%, and 87. 5%, respectively, while reducing electrolyte leakage and total soluble solids by 65% and 22%, respectively, compared to the same treatmentcondition without any superabsorbent. Therefore, it seems that superabsorbent can increase plant tolerance for counteracting moisturestress via maintaining unusable water.

In order to investigate the effect of foliar application of potassium sulfate (K2SO4; 0%, 1. 5%, and 3%) and iron chelate (Fe-EDDHA; 0%, 0. 5%, and 1%) on fruit set, fruit yield and quality, leaf mineral nutrient content, raisin yield, and autumn and winter cold toleranceof ‘ Bidaneh-Sefid’ grape, this study has conduced a factorial experiment, based on randomized complete blocks design in a commercialvineyard in Bahareh, Malayer, Iran, during 2016-2017. Vines have been sprayed during three stages, including one week beforflowering, as well as two and five weeks after corolla abscision. According to the results obtained, the combined effects of K2SO4 andFe-EDDHA have been significant on fruit set, fruit yield and quality, and raisin yield, not to mention vines' cold tolerance, wi th thehighest fruit set percentage and yield belonging to 1. 5% of K2SO4 in combination with 0. 5% iron chelate. The grapes' K, Fe, and Mnconcentration has had a positive and significant correlation with fruit yield per vine and the highest ascorbic acid concentration has beenobserved in vines, treated with 1. 5% K2SO4. It is also found that raisin yield has been the highest in combined treatments of 1. 5%K2SO4 and 1% Fe-EDDHA and the lowest in control vines (0% for both K2SO4 and Fe-EDDHA). The highest autumn cold hardinesshas been recorded in vines, treated with 3% K2SO4 and 1% Fe-EDDHA, whereas the highest winter cold tolerance has been achieved inthe ones, treated with 3% K2SO4 and 0. 5% Fe-EDDHA. The lowest cold tolerance belongs to control vines. There has been a positiveand significant correlation between cold tolerance and K content and a negative one with Mg concentration. Totally, the highest fruitand raisin yields and their desirable qualities have been obtained in K2SO4 and Fe-EDDHA with moderate concentration; however, thehighest bud’ s cold tolerance has been seen in the combination of these fertilizers with higher doses.