فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 39 (پاییز 1395)

To evaluate effect of photosynthate availability under terminal heat stress on yield and yield components of wheat, this research was conducted in a split plot experiment based on randomized complete block design (RCBD) with three replications at the Research Farm of Islamic Azad University of Ahvaz in 2015 cropping season. Treatments were defoliation in four levels: removal of two upper leaves, flag leaf removal, complete removal of spikelet at one side of spike and control (non-manipulated) which assigned to main plots and three planting date including (Nov. 21st , Dec. 5st and Dec. 21st ) to subplots. Results showed that defoliation had significant effect on number of grains/spike, 1000 grain weight, grain yield, biological yield and harvest index at one percent probability level. Planting date also affected number of spike/m2, number of grains/spike, 1000 grain weight, grain yield, biological yield, and harvest index significantly at one percent probability level. The interaction effect of defoliation and planting date on the number of grains/spike, 1000 grain weight, grain yield, biological yield and harvest index was also significant. The highest grain yield (5691 kg.ha-1) belonged to the control treatment (no defoliation) at first planting date (Nov. 21st). This was due to the not coinciding filling periods to terminal heat stress of growing season where maximum assimilates were produced. The lowest grain yield (2123 kg.ha-1) belonged to delayed sowing and removal of spikelet at one side of spike. Maturity of plants during 3rd planting date (Dec. 21st) was coincided to heat stress and thus reduced assimilate production.

In this study the effects of wheat (Triticum aestivum L.) and bean (Phaseolus vulgaris L.) residues, along with application zinc sulfate, on zinc, protein, phytic acid concentrations of wheat grain and grain yield were evaluated to do this an experiment based on randomized complete block design with 3 replications and six treatments (control, zinc sulfate, wheat residue, bean residue, wheat residue zinc sulfate and bean residue zinc sulfate) was conducted in Isfahan during growing season of 2012-2013. Results of ANOVA showed that there were highly significant differences between wheat and bean residues along with application zinc sulfate, protein, phytic acid in wheat grain, phytic acid to zinc molar ratio and yield. The results also showed that the highest grain yield, protein content and grain zinc concentrations were related to bean residues application sulfate zinc treatment and the lowest yield to control. The use of crop residue on the soil caused a significant increase in grain yield and shoot, as compared with that of the control (p

To study the effect of nitrogenous fertilizers and mixed cropping of legumes and maize on its grain yield and yield component of corn in Arak, an experiment was carried at the Agricultural Research Center of Markazi Province in 2013. A factorial experiment based on randomized complete block design with three replications was performed. Treatments were four levels of urea (N0= control, N1= 75 kg.ha-1, N2= 150 kg.ha-1, N3= 225 kg.ha-1) and mixed cropping with four levels (S1= planting corn, S2= planting corn chickpea, S3= planting corn cowpea, S4= planting corn mung bean). Plot consisted of 4 rows, 6 m long with 60 cm between rows space and 20 cm between plants on the rows, and S.C 704 corn hybrid was used. In this study characteristics such as: plant height, number of green leaf, grain yield, number of row per ear, number of grain per ear row, nitrogen use efficiency, biomasses of legumes, nitrogen percentage and 1000 grain weight were assessed. Results indicated that the effect of different levels of urea on plant height, number of green leaf, grain yield, number of grain per row, nitrogen use efficiency, legumes biomass and nitrogen percentage were significant. Effect of mixed cropping on characteristics like grain yield, nitrogen use efficiency, biomasses of legumes nitrogen percentage was also significant. Highest and lowest grain yield (7.37 and 5.47 t.ha-1) were obtained with the use of 225 and 75 kg.ha-1 urea, respectively. The highest and lowest grain yield (7.30 and 6.01 t.ha-1) belonged to sole cropping at corn and mixed cropping of corn mung bean, respectively.

To evaluate the effect of humic acid on some cultural characters of some alfalfa varieties, a field experiment was conducted as factorial split plot based on RCBD design with three replications in 2014. In this experiment, 5 varieties of alfalfa (Yazdi, Hamedani, Baghdadi, Bami and Ranger) and three levels of humic acid (5 and 10 lha-1 and without humic acid, as control) were considered as the first factor and harvest time was as the second factor. Result indicated that except plant height, other characteristics such as dry weight yield, dry weight per plant, root and shoot dry weight per plant, number of leaves and stem diameter were affected by triple interaction effect of harvest time×variety×humic acid. Plant height was affected by double interaction effect of variety×humic acid and also harvest time×variety. Yazdi and Bami had the highest and Ranger had the least values of traits under study in two cuttings, respectively. Also in the between of humic acid treatments, 10 lha-1 treatment produced highest traits measured as compared to control and 5 lha-1 treatment. Bami, Ranger and Yazdi varieties with 10 lha-1of humic acid in two cuttings produced the highest dry weight yield (3.64, 3.55 and 3.26 t.ha-1 respectively) in this experiment.

To determine the effects of potassium foliar application (with two levels, use and non-use) from potassium sulphate source and top-dressing application of potassium fertilizer (with two levels, use and non-use) from potassium chloride source on number of seeds per capitulum, number of side branch per plant, seed yield, seed oil content, oil yield, seed to coat ratio, plant height and shoot dry weight in three safflower, genotypes including KW.2, Padideh and Goldasht a factorial experiment based on the randomized complete block design (RCBD) with three replications, was conducted during 2013 growing season at the Agricultural Research Center of Semnan province (Shahroud). Results showed that the highest average of number of seeds per capitulum (28.70), number of side branch per plant (17.83) and seed to coat ratio (1.47) were found in KW.2 genotype. The highest seed yield (2627.7 kg/ha) and oil yield (1350.5 kg/ha) were found from potassium sulphate foliar application in Padideh and KW.2 genotypes respectively. The interaction effect of genotype × potassium foliar application was significant for seed and oil yields. In conclusion, it was determined that potassium sulphate foliar application has better impacts on seed and oil yield of safflower genotypes than potassium top-dressing application.

Micronutrients have an important role in growth and yield of plants. This investigatin was carried out to evaluate effect of foliar applications of three micronutrients (Fe, Mn and Zn) at different times (4-6 and 8-10 leaf stage) with three replication on sugar beet. Based on results obtained all of the micronutrients used increased sugar beet sugar yield. Highest root yield was obtained by using 9 % of micronutrients at 4-6 leaf stage, but other concentrations did not have any effect on sugar beet yield. All of the three micronutrient concentrations increased root yield significantly. Application of 6% concentration increased root yield by 15.6 %. Mn application did not have any effect on sugar yield. 9 % concentration of Zn foliar application increased sugar yield by 16.4 %, and application of 6 and 9% of Fe increased sugar yield by 18.6 and 36 % respectively. Sugar percent did not changed by Mn application, but high concentrations of Fe and Zn at 8-10 leaf stage increased it. Highest increase in sugar percent obtained by using Fe 9 % foliar appliction. Because of economical importance of sugar and root yield, foliar application of 9 % of Fe and Zn at 8-10 leaf stage will be suitable.

Environmenal problems resulting from application of nitrogen fertilizers in the production plant materials led agricultural specialists to use clean and alternative methods to towards the organic farming and use of organic fertilizers. In this study, thus, the effect of nitrogen and vermicompost fertilizer rates on yield, yield components, essential oil content and some morphological traits of marigold was studied in a split plot experiment based on completely randomized blocks design with 3 replications in Shahr-e-Rey region during 2013 growing season. Nitrogen rates with 3 levels (0, 60, 120 and 180 kg.ha-1) were assigned to main plots and vermicompost with 3 levels (0, 10, and 20 t.ha-1) to the sub plots. Mean comparison of simple effects indicated that the plants treated with 120 kg.ha-1 nitrogen fertilizer and 20 t.ha-1 organic fertilizer vermicompost produced higher trait values under study than control (non application of vermincompost). Interaction effect of experimented factors was significant on all traits under evaluation. Thus, highest seed yield (1567 kg.ha-1), biological yield (6664 kg.ha-1) and essential oil yield (8.85 kg.ha-1) obtained by the application of 120 kg.ha-1 nitrogen fertilizer and 20 t.ha-1 varmicompost. Based on the results obtained it could be said that nitrogen and vermicompost may improve seed and biological yield and yield components of marigold.

To study the effect of salicylic acid concentrations and foliar application times on yield and yield components of maize in the northern Khuzestan, a field experiment in 2014-2015, as factorial in the form of randomized complete block design with three replications was conducted. Experimental factors were salicylic acid concentration in five levels, 0, 0.25, 0.5, 0.75 1 Mm and foliar application times with three levels: once at 6-8 leaf stage, twice at 6-8 leaf stage and ten days after that, thrice at 6-8 leaf stage and twenty days after that. Results showed that the leaf area index, grain yield and yield components, like grain thousand weight, number of kernel rows per ear and number of kernels per row, were affected significantly by different salicylic acid concentrations and foliar application times, but the effect of salicylic acid concentration ×foliar application time interactions were not significant. Biologic yield was affected by different concentration of salicylic acid. The highest biologic yield of 18150 kg/ha related to 0.75 Mm salicylic acid concentration and lowest to control (no foliar application) with 15140 kg.ha-1, but the effect of foliar application times and their interactions were not significant. Foliar application of salicylic acid increased grain yield. The highest grain yield of 8998 kg.ha-1 related to 1 Mm concentration treatment and lowest (6897 kg.ha-1) to control (no foliar application). Highest grain yield (8592 kg.ha-1) belonged to two time foliar applications, at 6-8 leaf stage and ten days after that. The conclusion is that the application of salicylic acid could be beneficial in increasing grain yield of maize.

The effects of biological and chemical fertilizers, along with the use of salicylic acid, on the agronomic characteristics of corn in a factorial experiment based on randomized complete block design with three replications were evaluated at the Agricultural Research Station of Boroujerd in 2011. Factors were three levels of phosphorus fertilizer (0, 100 and 150 kg ha), two levels of biological fertilizers (mycorrhizal fungi) (inoculation and non- inoculation of seeds) and two levels of salicylic acid (0.5 and 1 mM), respectively. The results showed that phosphorus fertilizer and mycorrhizal inoculation of seeds affected number of seed rows, seed weight, seed yield and biological yield significantly. Seed yield of plants inoculated with mycorrhiza was 8412 kg.ha-1 which is 24% higher than non-inoculated ones. The effect of salicylic acid on plant height, stem diameter, ear length, ear diameter, number of seed rows, seed weight, seed yield and biological yield and harvest index was also significant. The yield of plants with 1 mM salicylic acid treatment amounted to be 8316 kg.ha-1 which is 24% higher than none treated ones. Phosphorus and mycorrhizal interaction on the number of rows of seeds, seed weight, seed yield and biological yield were significant. Salicylic acid and phosphorus interactions and three way treatment effects were only significant on grain yield. This study showed that salicylic acid and mycorrhizal inoculation of seeds can increase seed yield by improving yield components.

This study was aimed at the evaluation of yield and essence responses of two fennel (Foeniculum vulgare) local varieties to mycorrhiza under water stress conditions. It was performed in a split split plot experiment based on randomized complete block design at the Agricultural Research Station of Islamic Azad University, Tabriz Branch, Iran, during 2013. Factors under study were two fennel land races of Esfahan and Malayer assigned to main plots, three levels to irrigation (70, 100 and 130 mm evaporation from pan) to sub plots and use of two mycorrhizal strains (Rhizophagus intraradices and Funneliformis mosseaeas) and control to sub sub plot. Results revealed that relative water content of leaves in inoculated seeds were improved. It was also observed that chlorophyle content index of fennel leaves in inoculated plants increased by 39% compared to the control. When inoculated plants were irrigated at 100 mm evaporation from pan, it was increased in secondary branches by 4.7 per plant. Plants irrigated at 70 mm and 100 mm evaporation produced higher essence yield (18.5 l.ha-1), but its increase was only 11 l.ha-1 when plants irrigation at 130 mm evaporation. It is concluded that plants in semi arid areas may tolerate drought when seeds inoculated with mycorrhiza better than plants non-inoculated seeds.

To study the effects of irrigation regimes and organic fertilizers (compost and vermicompost) on mucilage percentage and some quality characteristics of borago (Borago officinalis) a field experiment was conducted in a split plot arrangement based on randomized complete block design with three replications at the Research Farm, Faculty of Agriculture, University of Zabol, Iran during 2012. Irrigation regimes were S1: 100% FC, as control, S2: 80% FC (moderate stress) and S3: 60% FC (severe stress) and application of organic fertilizers: N1: without fertilizer as control, N2: 40 t.ha-1 compost, N3: 4 t.ha-1 vermicompost were assigned to main plots and sub plots, respectively. The results showed that N, P and K, as well as the amount of chlorophyll a, carotenoid and total chlorophyll content decreased with increasing drought stress, but decreasing effects of fertilizers levels on traits were not high. Stress conditions and application of compost increased sodium percentage. By increasing drought stress, soluble carbohydrates and mucilage percent also increased. Highest mucilage percent (2.37) was obtained from moderate stress treatment. Highest total dry yield (13.48 t.ha-1) was also due to non-stress conditions. This was not significantly different mild stress. Application of organic fertilizers, particularly compost, resulted in greater performance. It can be concluded that acceptable yield of dry borage and higher mucilage percent can be obtained from irrigation at 80 percent field capacity and use of compost in Zabol climatic condition.

To calculate correlation coefficients and path analysis of some traits related to grain yield, 15 genotypes of safflower were studied under non-stress and drought stress conditions at two different sites (with 10 meter distance) in the field of College of Agriculture of Lorestan University, Iran. Each experiment was conducted in a randomized complete block design with three replications. Analysis of variance showed that there were significant differences among the genotypes for all measured traits and yield in both stress and non- stress conditions. By using stepwise regression, best model was estimated for the two conditions. Sequential path analysis of the correlation between grain yield and other traits showed that days to start flowering, 1000-seed weight and stem diameter had direct effects on grain yield under non-stress conditions, while under drought conditions, seed weight per plant and 1000-seed weight had direct and positive effects on grain yield. Thus, to obtain high yielding varieties of safflower under drought stress condition, we showed attempt to select varieties with high seed weight per plant.

Salinity is one of the main factors to reduce crop production worldwide, especially in dry land farms. In this study the effect of pretreatment of wheat seed with hydrogen peroxide (H2O2) on various traits of wheat (Sardary) including morph-physiological parameters and yield components under salinity conditions were evaluated. This experiment was carried out in a randomized complete block design with three replications, in greenhouse. Treatments were three salinity levels (0, 80 and 120 Mm) and four concentrations of hydrogen peroxide (0, 25, 50 and 80 Mm). In this study, salinity affected all of yield components, levels of antioxidants, photosynthetic pigments, length and number of leaf stomata. Pretreatment of seed with hydrogen peroxide alleviated the effect of salinity on yield through positive effect on plant water relation, pigments, leaf area and stomata. Plants from pretreatment of seed with hydrogen peroxide had higher relative water content, chlorophyll and carotenoid pigments, leaf area and lower number of stomata and larger length of stomata under salt stress condition as compared with control. Seed pretreatment with hydrogen peroxide also reduced the adverse effect of salinity.

Quantitative and qualitative traits and stability of marketable tuber yield of 14 promising potato clones, along with three commercial cultivars (Agria, Marfona and Savalan) as checks, were evaluated at the Ardabil Agricultural and Natural Resources Research Station during 2013 and 2014. The experiment was based on a randomized complete block design with four replications. During growing period and after harvest, traits like main stem number per plant, plant height, tuber number and weight per plant, total and marketable tuber yield, dry matter percentage, baking type, hollow heart, tuber inner ring and discoloration of raw tuber flesh after 24 hours were measured. Combined ANONA for quantitative traits showed that there were significant differences among promising clones as to total and marketable tuber yield, tuber number and weight per plant, plant height, tuber mean weight, main stem number per plant and dry matter percentage and their interactions with year in total and marketable tuber yield. The clone 9 (397078-3) with the least amount of marketable tuber yield had significant difference with clones 4 (397045-13), 1 (397031-16), 3 (397031-11), 6 (397009-8) and 12 (397067-6) in 2013 and with clone 4 (397045-13) and Agria cultivar in 2014. The clones 4(397045-13), 1 (397031-16) and 12 (397067-6) had uniform tuber, yellow to dark-yellow skin and light-yellow to yellow flesh color, tuber shape of oval round and round, shallow to mid shallow eyes, no tuber inner ring, hollow heart and tuber inner crack and mid-late maturity. They were selected for home consumption of chips, french-fries and frying. Based on the results of factor analysis, "tuber yield", "number of tuber" and "plant structural and quality "were named as first, second and third quality determining factors respectively. In this experiment, GGE Bi-plot model and AMMI Stability Value (ASV) parameter, were acceptable methods for the selection of marketable tuber yield stability which found to be simultaneously could introduce clones 1 (397031-16), 3 (397031-11), 4 (397045-13) and 12 (397067-6) to be selected as stable clones with high marketable tuber yield.

In this study, the Rysto gene, originaly found in wild potato (Solanum stoloniferum), confers extreme resistance against PVY. It was identified in 21 potato clones and varieties and they were evaluated for some agronomic traits. For this purpose five trials were conducted. In first trial 320 potato genotypes were planted on the farm and 55 symptomless clone and cultivars were selected. In second trial, 55 genotypes along with sensitive control genotype (Desireh) were planted in 20 cm pots in the greenhouse at 15-20 °C with three replications. After five weeks, upper leaves were infected artificially with sap from tobacco fresh leaves checked for infection with PVYNTN and additional infections were repeated after 48 hours. Symptoms were recorded and all plants were tested by enzyme-linked immunosorbent assay (ELISA) about 4 weeks after inoculation. Plants that showed visual symptoms or/and gave at least a positive ELISA result were considered as susceptible and symptomless response with negative ELISA results were considered as resistant. In third trial, 23 genotypes were planted in the greenhouse and the PVY infected young tobacco shoots were grafted to symptomless genotypes with negative ELISA results with three replications and were selected as resistance genotypes. In fourth trial, all the PVY resistant genotypes were checked by molecular marker (STM0003) for detection of Rysto gene. Finally four potato varieties (Jelly, Sante, White Lady and Savalan cultivars) and 19 advanced clones were regarded as carriers of Rysto gene. In the fifth experiment genotypes were evaluated for marketable tuber yield of varieties and clones resistant to virus PVY in field conditions and 397009-8 clone was selected as high-yielding and tolerant genotype to PVY virus. Also, This clone did also have appropriate quality traits like oval-round tuber shape, uniform tubers, short stolon length, light yellow flesh color, yellow skin color, good tuber dry matter percent, tuber flesh texture of relatively soft (multipurpose) and shallow depth tuber eye.

To evaluate effects of the various concentrations of two herbicides of the trifluralin and Imazethapyr and weeding on weeds control, yield and yield components of soybean (Glycin max L.), an experiment was carried out based on randomized complete block design with three replications at the Agriculture Land of Ghravolhaji Village in Kallale district of Golestan province in 2014. Treatments consisted of planting soybean under weeding, without weeding and application of trifluralin and Imazethapyr as 100% trifluralin, 75% trifluralin 25% Imazethapyr, 50% trifluralin 50% Imazethapyr, 25% trifluralin 75% Imazethapyr, 100% pursuit, 100% Imazethapyr 25% trifluralin, 25% Imazethapyr 100% trifluralin, 100% Imazethapyr 50% trifluralin and 50% Imazethapyr 100% trifluralin. density of each weed, their total density and inhibition percentage were measured. Results showed that the effect of chemical weed control on all traits measured, except seed number per pot, 1000 seed weight, content of chlorophyll a and total chlorophyll, were significant. The highest leaf area, plant height, number of pods per plant, aerial plant dry weight, seed number per plant and seed weight per plant were observed in the treatment of the 100% Imazethapyr (238.67 cm2), weeding (57.69 cm), both treatments of weeding (33.10) and 25% Imazethapyr % trifluralin (28.3), both treatment of weeding (163.92 g) and 100% Imazethapyr (163.70 g), weeding (67.10 seed per plant), both treatment of weeding and 100% Imazethapyr 50% trifluralin (10.27 seed per plant) respectively. The highest seed yield was obtained from weeding treatment (2383 kg/h). Based on the results, the highest content of protein and chlorophyll b in soybean were obtained from weeding treatment. The highest inhibition percentage of weeds was found in the additional treatment of 50% Imazethapyr 100% trifluralin (75.19) and 100% Imazethapyr 25% trifluralin (72.86). The lowest and highest total phenols content and proteins also were obtained in the treatment of 100% trifluralin. Although treatments mentioned above had inhibitory effects on weeds they also decreased the yield components and seed yield of the soybean.

Water or soil salinities are the most important factors that reduce the seed germination of plants. Ethephon can break seed dormancy in a variety of plants, such as cereals and speeds up germination. In some plants pretreatment of seeds with salicylic acid has increased the germination percentage. To study effect of salicylic acid and ethephon on seed germination of wheat (Seivand cultivar) under salinity condition a factorial experiment in a completely randomized design with three replications was conducted at the Plant Research Laboratory of Neyshabur Branch of Islamic Azad University in 2011. Four salinity levels (0, 50, 100, 150 mM), three salicylic acid levels (0, 0.5, 1 mM) and four ethephon levels (0, 0.5, 1, 2 mM) were used. The results showed that at salinity condition seed germination rate and percentage, shoot and root length, their dry weight and α-amylase activity decreased and proline content increased. Pretreatment of seeds by salicylic acid increased seed germination percentage, some growth parameters, α-amylase activity and proline content under salinity condition. Moreover, pretreatment of seeds by ethephon decreased some growth parameters and increased proline content but its effect on germination and α-amylase activity were not significant. It seems that Salicylic acid as a plant growth regulator under salinity condition and ethephon convertion to ethylene, activated plant tolerance mechanisms to salinity condition and decrease damaging effect of salinity on seed germination and seedling growth of wheat.