مجله به زراعی کشاورزی
سال بیستم شماره 3 (پاییز 1397)

This research was conducted to investigate the effects of different seed coating treatments on the seed germination of canola under drought and salinity stresses. In order to, two factorial experiments were conducted based on completely randomized design with four replications in laboratory. In both experiments, one of the factors were 10 different seed coating treatments. The second factor was different in two experiments: in the first experiment, the levels of drought stress of 0, -0.8, -1, and -1.2 MPa were considered, and in the second experiment, the levels of salinity stress of 0, 7, 14 and 21 ds/m NaCl were investigated. Results indicated that the lowest hydrotime constant (θH) were observed in T9 (22.627 MPa h), T3 (22.538 MPa h), and T6 (22.263 MPa h). The lowest base water potential (Ψb (50)) were belonged to T4 (-1.332 MPa) and T1 (-1.324 MPa). The maximum of germination percentage under salinity stress (Gmax) was observed in T2 (86.75%). The highest threshold to salinity tolerance (Xo) was belonged to T3 (16.38 ds/m). The highest germination rate was belonged to T3 in all levels of salinity. Totally, seed coating treatments of T3, T6 and T9 were the best treatments under drought stress and T3 was the best treatment under salinity stress.

In order to evaluate the increment possibility of bean seed yield by the application of brassinosteroid, a split factorial experiment was conducted based on randomized complete block design with three replications at the research farm of Agriculture Faculty, the University of Zanjan during the 2016-2017 cropping season. In this experiment, irrigation levels included optimal irrigation and drought stress were applied to main plots and bean cultivars including Kusha cultivar and COS16 genotype, and four levels of brassinosteroid including of no-application (control), two, four and six μM were allocated to subplots as factorial. Drought stress was applied at the flowering stage, and bean plants were sprayed with brassinosteroid (epibrassinolide) simultaneously with drought stress. The results showed that drought stress decreased leaf area index, yield components, seed yield, biological yield and harvest index and the application of epibrassinolide minimized the negative effects of drought stress and increased in the above traits. The highest seed yield was obtained by application of two μM of epibrassinolide with an average of 2068.2 kg.ha-1. Also, among the studied cultivars, the Kusha cultivar under optimal irrigation with an average of 3025.45 kg.ha-1 showed a higher seed yield compared to COS16 genotype. Therefore, the use of epibrassinolide can be suggested as a solution to increase drought stress resistance and enhance seed yield of bean under optimal irrigation and drought stress conditions.

In order to evaluating effect of smoke-water and urea fertilizer on some growth indices, grain yield and yield components of wheat, a field experiment was conducted as a split plot based on Randomized Complete Block Design with three replications. The experiment was conducted during the season of 2015-2016 at Razi University Research Station, Iran. The experimental treatments were different levels of urea fertilizer application (included 90, 180, 300 and 360 kg ha-1) as main plot and leaf foliar application with different concentrations of smoke-water (included 0, 0.001%, 0.01%, 0.1% and 1% v/v) as sub plot. The results showed that smoke-water significantly improved all evaluated traits and increased wheat grain yield compared to control treatment in all urea fertilizer levels. The highest grain yield (922 g m-2) was obtained in application of 350 kg ha-1 urea and smoke-water at concentration of 1% v/v and the lowest grain yield (339 g m-2) was related to application 90 kg ha-1 urea and foliar with distilled water. The grain yield improved 15.22%, 11.36%, 7.18% and 7.67% by application of 90, 180, 300 and 360 urea kg ha-1 respectively, in smoke-water 1% concentration compared to the control treatment. It seems that smoke-water via improve increasing nitrogen efficiency could increase growth indices and grain yield of wheat.

In order to study the effect of terminal drought stress on agronomic and qualitative traits of canola genotypes in the application of ammonium sulfate condition, an experiment was performed during two years of 2015-2016 and 2016-2017. This study was conducted as a factorial split-plot design based on completely randomized block design with three replicates at the research farm of the Seed and Plant Improvement Institute (SPII). At the pod formation stage, irrigation factors were included two levels, normal and restricted, and at the elongation stage, ammonium sulfate was included two levels of 0 and 150 kg per hectare, as factorial was set in the main plots and cultivars including BAL111, BAL119, BAL121, BAL128, and Nima were set in subplots. The results showed that among the genotypes examined, line BAL128 had the highest grain yield (3904 kg/ha), which increased 28% compared with the control treatment. The highest amount of grain oil (45.53 percent) was obtained in the second year of experiment and under normal irrigation conditions. By application of ammonium sulfate, the amount of oil increased by 2.5 percent in comparison with normal condition. The BAL128 line had the highest percentage of grain oil (44.29%). in normal irrigation condition, the use of ammonium sulfate resulted in decreasing the amount of glucosinolate to 22.88%. However, in restricted irrigation condition, the amount of glucosinolate decreased to 17.25 percent. In the irrigation and fertilizer treatments of this experiment, among the lines studied, The BAL128 line is recommended for similar experimental conditions.

In order to study the effect of N rate and plant density on grain yield and N use efficiency of blessed thistle, a field study ‎was carried out in a randomized complete block design with factorial arrangement of treatments in three replications‏ ‏at ‎Research Field of Tarbiat Modares University in 2013 and 2014 growing seasons.‎‏ ‏Treatments comprised of four pure N ‎rates (0, 50, 100 and 150 kg N ha-1)‎‏ ‏from urea source and five plant densities (5, 10, 15, 20 and 25 plants m-2).‎‏ ‏The main ‎effects of nitrogen and plant density were significant for grain yield, NUE, plant height, SPAD value, root to shoot weight ‎ratio and N content of grain. Increasing N rates increased grain yield, SPAD value, plant height and grain N, but agronomic ‎efficiency, N recovery and utilization were decreased by increasing of N rate; Higher densities resulted in decreased grain ‎yield and chlorophyll index, while improved NUE throughout increment of root to shoot weight ratio and plant height‏.‏‎ ‎Novel findings of this study could be used for N management. ‎

In order to investigate the effects Azoto of irrigation cutting and chemical and biological fertilizers, Azoto Barvar 1 and phosphate Barvar 2 on grain yield, essential oil and biochemical properties cumin, an experiment was conducted as split plot based on a randomized complete block design with three replications at the University of Zabol Research Farm during 2016. Main plots included four levels of irrigation cutting; conventional irrigation, irrigation cutting in between stem elongation to flowering, irrigation cutting in between flowering to beginning of the grain filling period and irrigation cutting in between beginning to end of grain filling period. The subplot was the different type of phosphorous fertilizer including control (no fertilizer application), Azoto Barvar 1 and Phosphate Barvar 2 and triple superphosphate. Results indicated that the interaction of irrigation cutting and phosphorous fertilizer was 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 obtained at conventional irrigation along with the application of Azoto Barvar 1, while the greatest proline was achieved at irrigation cutting between beginnings to the end of grain filling period along with the application of triple superphosphate. The greatest carbohydrate was observed at irrigation cutting between beginnings to the end of the grain filling period along with the application of Phosphate Barvar 2. In conclusion, results indicated positive effects of biofertilizers on the improvement of nutritional conditions of plants under irrigation cutting conditions

In order to investigate the morpho-physiological responses of Purslane plant to methyl jasmonate under salinity stress a split plot based on a completely randomized design with two factors and three replications was carried out in medicinal plants research center, Shahed University, Tehran during 2017. The factors were, salinity with four levels (0, 3, 6 and 9 dS/m) as a main factor and methyl jasmonate with four levels (0, 0.25, 0.5 and 0.75 mM) as a sub factor. The results showed that by increasing salinity levels, the growth indices such as root length, fresh weight of root, chlorophyll b, total chlorophyll and the amount of superoxide dismutase decreased, while by increasing the salinity levels the proline content and the activity of catalase and MDA in the leaf increased. Applying methyl jasmonate under salinity stress reduced the growth indices and photosynthetic pigments. The highest number of branches, number of leaves and chlorophyll b was obtained at 6 dS/m salinity and 0.5 mM methyl jasmonate. By increasing methyl jasmonate level, the proline content and the activity of CAT increased, while the amount of MDA and SOD enzymes decreased. Therefore, it can be concluded that the is the tolerance of Portulaca oleracea plant to salinity was up to six dS/m, and consuming low amounts of methyl jasmonate can improve yield and physiological indices in Purslane.

In order to study the most suitable planting date, planting site and variety of hoary stock for the supplying at spring season, an experiment was conducted as split-split-plot arranged based on randomized complete block design with three replications at experiment station of Shahid Bahonar University of Kerman in 2016-2017. Treatments were planting dates (5 September, 5 October, 5 November, 5 December, 5 January) assigned to main plot, planting sites (inside and outside of greenhouse) as subplot and variety (two red and white ecotypes and two violet and pink breeding varieties) as sub-subplot. The significant difference of planting date was detected in plant height, number of days to budding and flowering, floret and inflorescence diameter, number of florets per plant, fresh weight of floret and plant, and vase life of flowers but did not detect in inflorescence height. The planting site had significant effect on all the traits except plant height, inflorescence height, and leaf number per plant. The results showed that the delay in planting decreased number of days to budding and flowering in all the varieties and both planting sites. The growth period of local varieties was longer than the breeding varieties, significantly. Planting outside the greenhouse had more appropriate conditions than inside. In general, planting the local red variety at 5 October and out of greenhouse conditions was the most suitable treatment for supplying the hoary stock to the market on the first of spring.

In order to determine the best time and amount of Glycine Betaine (GB) in increasing tomato yield in drought stress condition, an experiment was carried out in Split Plots on RCBD design with four replications, during 2016. The experimental factors included main factor (irrigation period in 6 and 12 days) and sub factors including time (in 3 levels including sowing, flowering and fruit set) and amount (in 3 levels including 0, 3 and 6 kgha-1) of GB application. The results from RWC, leaf area and electrolyte leakage showed the efficiency of GB application in stress condition. Using GB in non-stress condition led to decrease in fruit weight and no significant difference was observed between 3 and 6 kgha-1 dosages. In stress condition, 3 kgha-1 GB application in sowing, flowering and fruit set stage increased fruit weight by 33%, 40% and 60% respectively compare to average fruit weight of control treatments. Although the positives effect of 3 kgha-1 GB at flowering time on fruit yield was obvious (62% higher) in this study, it seems that the application of this amino acid in non-stress conditions had some toxic effects on tomato fruit yield.

Since the regulated deficit irrigation and subsurface irrigation cause to increase high water use efficiency and water saving, a field factorial experiment was carried out based on randomized complete block design with three replications at the South Kerman Agricultural and Natural Resources Research and Education Center during 2014-2016. In this study, two factors including deficit irrigation (100 percent ETc in total growing stages, 60-100 percent and 80 percent ETc except in the flowering and fruit-filling stages) and irrigation method (deep subsurface, subsurface drip and surface drip irrigation) were evaluated. Vegetative traits, yield and water use efficiency were measured during growing period of sweet orange (Citrus sinensis var. Mars Early) grafted on Citrus aurantium. The results showed that the regulated deficit irrigation practices save water compared to complete irrigation of about 17 percent and reduce vegetative growth, although there were no statistically significant differences in yield. Subsurface irrigation saved water compared to surface drip irrigation of about 10 percent, improved 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 use efficiency and water saving.

Considering the limited water resources in Iran, utilization of modern methods of water conservation and preservation, such as the application of superabsorbent polymers in the soil, is one of the confront approaches of water deficit. For this purpose, in order to investigate the effect of superabsorbent on vegetative and reproductive growth of Page Mandarin in drought stress condition, a factorial experiment bases on the completely randomized design with three replications was conducted in 2016 at the Citrus and Subtropical Fruits Research Center of Ramsar. Factors were consisted of three levels of water stress (100, 75 and 50% of field capacity) and superabsorbent (0, 0.25 and 0.5% wt). The results showed that by increasing of water stress, amounts of electrolyte leakage, proline, fruit cracking and titratable acidity were increased. As well as 50% of field capacity level, 0.5% superabsorbent application was caused significantly increase leaf relative water content, total chlorophyll content, leaf water potential 60%, 15%, 23% and 87.5% and decrease electrolyte leakage and total soluble solids 65% and 22% respectively, compared with condition of treatment without applying superabsorbent. So, it seems that superabsorbent can increase the plant tolerance in counteracting moisture stress by maintaining unusable water.

In order to investigate the effect of foliar application of potassium sulfate (K2SO4; 0, 1.5 and 3 percent) and iron chelate (Fe-EDDHA; 0, 0.5 and 1 percent) on fruit set, fruit yield and quality, leaf mineral nutrient content, raisin yield and autumn and winter cold tolerance of ‘Bidaneh-Sefid’ grapevine, a factorial experiment was done based on randomized complete blocks design in a commercial vineyard in Bahareh village of Malayer city during 2016-17. The highest fruit set percentage and yield was achieved in 1.5 percent of K2SO4 in combination with 0.5 percent iron chelate. Berries K, Fe and Mn concentration had a positive and significant correlation with fruit yield per vine. Raisin yield was found to be highest in combined treatments of 1.5 percent K2SO4 and 1 percent Fe-EDDHA and the lowest raisin yield was related to control vines. The highest autumn cold hardiness was recorded in K2SO4 (3%) × Fe-EDDHA (1%) treated vines. However, the highest winter cold tolerance was achieved in K2SO4 (3%) × Fe-EDDHA (0.5%) treated vines. The lowest cold tolerance was observed in control vines. There was a positive and significant correlation between cold tolerance and K content and negative correlation with Mg concentration. Totally, the highest fruit and raisin yields and their desirable qualities were obtained with K2SO4 and Fe-EDDHA at moderate concentration. However, the highest buds cold tolerance was obtained with the combination of these fertilizers at higher doses.