مجله علوم گیاهان زراعی ایران
سال چهل و هفتم شماره 4 (زمستان 1395)

Potato is one of the susceptible crops to drought. This research was carried out as a split factorial experiment in a randomized complete block design with three replications in Karaj in 2014. Potato genotypes at 11 levels (Agria, Caesar, Savalan, Sante, Marfona, Milva, Picasso, Hermes, Jelli, 397081-1, 397069-2), irrigation treatment in two levels (stress and control) and samplings in two stages (after stress and recovery) were considered. Irrigation was done as drip and conventional systems and in the stage of tuber production, watering for stress treatment was stopped and control treatment was irrigated normally. After getting to ninety percent of the soil moisture deficit, irrigation restarted until the soil moisture reached to the field capacity and normally continued up to the end of growing season. The results showed that there were significant differences among genotypes, the irrigation levels and the stages of measurement for large and small diameters of the tubers, number of tubers and healthy tubers, the tuber smaller than 35 and larger than 55 mm, dry and fresh weight of the healthy tubers per plant. However, number of tubers between 35-55 mm was, significantly different for the genotypes and irrigation levels. The most changes were observed in the tuber number smaller than 35 mm, dry and fresh weight of the healthy tubers. In addition, in this research, genotypes were categorized in 4 groupes according to the estimated drought tolerance and sensitivity indices.

This study carried out to investigate the effect of supplemental irrigation and nitrogen application times on seed yield and agronomic characteristics of dryland wheat (Triticum aestivum L.) Kohdasht variety in Gachsaran dryland agricultural research station. For this purpose, the irrigation times in main plots (Rainfed, Planting, Flowering, Planting Flowering with rates of 50mm) and different nitrogen rates (0, 30, 60, 90 and 120 kg.h-1) in sub plots were studied based on RCBD split plot design for three consecutive years, during 2009-12 seasons. According to the results, the relationship between the amount of applied nitrogen and seed yield following the quadratic regression equation and average requirement of nitrogen for Kohdasht variety wheat was determined 80 kg.h-1 to achieve 95 percent of maximum seed yield. This value change of nitrogen, could explain 86 percent of variation in grain yield (R2=0.86). Also among supplemental irrigation treatments, the amount of 50 mm irrigation at wheat flowering stage compared to rainfed (non-irrigated), increased grain yield by 43 percent. Finally, according to the findings of this study, it is necessarily recommended to apply 80 kg.h-1 nitrogen in combination with supplemental irrigation at wheat flowering stage, to improve and increase yield.

In most regions with mediterraneanclimate such as Iran, wheat farming is faced to drought and heat stresses at grain filling period and consequently a sharp decrease in grain yield. The evaluation of heat stress on wheat cultivars yield in Jarahi Mahshar region, was conducted through a split plot design with randomized complete block basis with three planting dates as the main factors (First: 2014.11.6, Second: 2014.12.6 and Third: 2015.1.5) and three cultivars of wheat (Chamran, Falat, Virinak) as sub-plots with three replications in cropping season 2014-15. Results showed that planting date and the cultivars had a significant impact on grain yield, yield components, spike height, biological yield, harvest index, the scale of redistribution, share of redistribution, efficiency of redistribution, length of spike, amount and efficiency of current photosynthetic. Interaction effect between planting date and the cultivars significantly impact on the numbers of spike per square meters, the number of grains per spike, grain weight (1000 numbers), grain yield, scale of redistribution, efficiency of redistribution, amount of current photosynthesis, biological yield, harvest index, spike length, share of redistribution and current photosynthesis efficiency. Chamran had the highest yield with average of 5548 kg.ha-1 in first planting date and Falat had the lowest yield with an average of 2100 kg.ha-1 in third planting date.

The existence of genotype × environment interaction necessiate the assessment of genotypes yields in wide range of environmental conditions, so that obtained information could increase their selection and introduction efficiency. In this study to determine the yield stability and analysis of genotype × environment interaction pattern, 66 mutant lines of rice with 5 check cultivars were evaluated using a randomized block design with three replications for three years (2012-2014). Analysis of additive main effects (analysis of variance) and multiplicative interaction effects (principal components analysis) revealed that the effects of genotype, year, and interaction between of them were highly significant. Total interaction effect was divided into one significant interaction principal component at 5% probability level and residual (noise) via AMMI model. The first principal component explained 57.57% of the total variation. Biplot of the first principal component and mean yields (AMMI1 model) for evaluated genotypes and environments (years) revealed that high yielding genotypes of G7, G41 and G69 with the least genotype × environment interaction effect were more stable genotypes and G63, G20 and G33 with yield lower than average recognized as unstable genotypes.

This experiment was conducted to study the effect of plant density and sowing season spring and Summer on quantitative characteristics and yield of corn (704 maize hybrids), Split-plot arrangement in randomized block design with three replications was used and during 2015 in Andimeshk. The different densities of 65, 75, 85 and 95 thousand plant per hectare was considered as main plots and sowing season in two levels sowing Spring (25 March) and sowing Summer (21 July) were randomized in sub-plots. Results showed that The effect of plant density on was significant in all the tested characters exception The number of active leaves and leaf fag. The effect season sowing on traits such as number of active leaves, leaf fag and 1000 grain weight were not significant. with of plant density increasing from 65 to 75 thousand plant per hectare increased fresh forage yield, but in densities Above was decreased. The highest grain yield in density of 65 thousand plant per hectare and Related was to sowing Summer. based on the findings of this experiment and in order to achieve the highest fresh forage yield in sowing spring and the plant density of 85 thousand plant per hectare in the Khuzestan and other regions with similar ecological conditions are recommended.

In order to study the effect of organic and inorganic fertilizers on quality and quantity production of fodder Amaranth (Amaranthus spp. L.) a field experiment was conducted in agricultural faculty of Shahid Chamran University in 2015. The experimental design was split plot based on RCB with three replications. Main plots were including Organic 1, Organic 2, Chemical, Integrated and Control and subplot including 2 Amaranth cultivars (Plansman and Koniz). Our results showed that both organic methods and Koniz Cv. had the highest plant height, leaf and stem dry matter and total dry matter. The highest fodder yield (368 gr/m2) belonged to Koniz Cv. with organic 2 methods due to better stem and leaf dry matter. Total dry matter production had the highest significant correlation with stem dry matter. Both organic methods had the highest digestibility, metabolic energy, crude protein and water soluble carbohydrates. No significant differences observed between cultivar for quality characters. Application of integrated method in Koniz Cv. had highest digestibility (57 percent) but had no significant differences with organic 2 methods. The highest crude protein (17 percent) belonged to Cv. Plansman with Organic 1 treatment. Total dry matter had positive correlation with digestibility but negative correlation with crude protein. In conclusion, we found that appling organic fertilizer methods will have good effective on quality and quantity of fodder production from Amaranth in Khuzestan.

In order to modeling of growth stages and yield of corn according to Hamedan province meteorological data (minimum and maximum temperature, radiation and rainfall) By using the sub models of phenology, production and distribution of dry matter and leaf area changes in maize studies was conducted at the Faculty of Agriculture, University of Vali-e-Asr Rafsanjan in spring 2015. Daily changes of phenology, total dry matter and leaf area was calculated using the model and the yield was predicted. One of the criteria to evaluation of a model is Comparison between coefficients of linear regression of observed and predicted yield (b=0.29±2.11 and a=0.93±0.23) and coefficients of line 1:1 (1, 0). Accuracy of the model related to coefficient of variations of predicted and observed seed yield (CV=4.13) was very high so that in field experiments coefficient of variations limit is 20 to 25. R2 quantity of seed yield was 0.69; showing that the probability for coordination of predicted and observed data is 69 percent. The Root mean square error is the other statistics which is used to evaluation of model accuracy. The Root mean square error of seed yield was 0.36, which is evidence of accuracy of model for yield prediction. domain variation for observed and predicted data were 8.54-9.99 tones and 8.02-9.25 tons per hectare respectively and the means were 9.09 and 8.75 tones per hectare respectively.

The present study was carried out in order to examine the effects of different cultivation dates on the properties of panicle and the yield of rice cultivars using a split plot design in the form of a randomized complete block basis with three replications in the crop year of 2010-11. The main factor was cultivation date at three stages (26 May, 10 and 26 July) and the sub-factors were Red Anbouri (long and short) and Champa. The results of the variance analysis indicated that the effect of cultivation date and the cultivar on the yield of the rough rice was significant at a level of 1%. First cultivation date resulted in maximum total dry material with an average of 13810 Kg.ha-1, maximum flag leaf width with an average of 1.14 cm, height with an average of 120.89 cm, and number of plants with an average of 504 plants per square meter. The second cultivation date caused the maximum flag leaf length with an average of 33 cm, day up to 50% of flowering with an average of 108 days. The third cultivation date led to the maximum yield of rough rice with an average of 4269.33 Kg.ha-1, harvest index with an average of 40.01%, the number of florets and seeds with averages of respectively 187.67 and 161.44 per cluster, the dry weight of flag leaf with an average of 0.14 gr and day until full maturity with an average of 144 days. As a result, the third cultivation date due to avoid susceptible panicle emergence to heat stress, is the best time of rice cultivation to achieve the highest agrain yield in Kuhzestan.

In order to study of the interaction between mycorrhizae symbiosis, soil and foliar spary of Flomix on yield and yield components of corn (Zea may L.), a factorial experiment was carried out based on Randomized Complete Block Design (RCBD) with three replications in Agriculture Research Staion of Shahrood University of Technology in 2014. The treatments included mycorrhizae symbiosis at 2 levels (check and application of mycorrhizae), foliar spray at 3 levels (check, once sprayed and twice sprayed) and soil spray at 3 levels (check, once soil application and twice soil application). The results of variant analysis showed that interaction between mycorrhizae symbiosis, soil and foliar spray of Flomix significantly increased biological yield, harvest index, 1000-seed weight, grain nitrogen content, and number of row per ear traits. Also grain yield and number of seed per row was significantly affected by interaction between foliar spray and soil spray. In addition, interaction between mycorrhizae and foliar spray significantly affected on seed depth trait. Mean comparisons showed treatments combination of twice foliar spray뜈 soil spray of Flomix increased seed per row and once foliar spray뜈 soil spray of Flomix increased grain yield. According to the mean comparisons results, treatment combination of foliar spray once soil spray flomix let to 2090 kg.h-1 grain yield. The lowest grain yield obtained from check treatment 1444 kg.h-1. The highest biological yield equivalent to 6557 kg.h-1 resulted from treatment combination of mycorrhizae symbiosis twice foliar spray once soil spray of flomix and the lowest biological yield equivalent to 3190 kg.h-1 obtained from chck treatment.

In order to evaluate the response of bulb yield per plant, chlorophyll content and photosynthetic pigments concentration to priming and seed size of onion genotypesa field experiment was conducted in 2012 and 2013 cropping season at Agriculture and Natural Resources Research Center of East Azarbayjan, Iran. The experimental treatments included priming (at four levels: hydro priming, osmopriming (in %2 KNO3), priming with Folammin amino acid (in 2%) and control (without priming), seed size (at three levels: small, medium and large) and cultivars (at two levels: Red Azarshahr and Zargan). Following characteristics such as bulb yield per plant, chlorophyll content including: bulbing stage, physiological maturity stage, photosynthetic pigments concentration including: chlorophyll a, chlorophyll b, carotenoid, total chlorophyll and chlorophyll a/b ratio of onion were studied. Analysis of variance of data showed that all studied characters were significant in 1% level of probability. Results showed that seed priming and seed size improved bulb yield per plant, chlorophyll content and photosynthetic pigments concentration characteristics. The highest bulb yield per plant, chlorophyll a, chlorophyll b, chlorophyll a/b ratio were obtained from plant that primed with Folammin amino acid 195.85 (g), 33.48, 7.79 (mg/g.FW), 4.3, respectively and the lowest were achieved from control plants. Also mean comparison indicated that the higher values of bulb yield per plant, chlorophyll a, chlorophyll b, chlorophyll a/b ratio were obtained from large seed size 180.66 (g), 21.60,7.20 (mg/g. FW), 3.9, respectively and the lower of it achieved from small seed size.

Seed priming is a method which is effective in improving germination and seedling establishment under stress conditions. To investigate the effects of seed priming on emergence and morphological characteristics of root of three canola cultivars, an experiment was arranged in a randomized complete block design in split plot with three replications. Main factors including five sowing dates with an interval of ten days and three canola cultivars and priming treatments including priming with water, zinc sulfate and control as sub plots were arranged in a factorial experiment. Results showed the highest emergence rate was achieved in Okapi by zinc sulfate priming with an average increase of 32 percent in all sowing dates. The most of the fresh and dry weight of three cultivars resulted from the first sowing date, 6 September. Sowing date October 16 under the hydropriming and primed with zinc sulfate increased root length by 7 and 10 percent in the Okapi, 18 and 23 percent in Zarfam and 32 and 35 percent in Talayeh compared with their controls, respectively. Root volume of Okapi on September 26, October 6 and 16, increased respectively 38, 61 and 71 percent in hydropriming and 51, 67 and 47 percent by priming with zinc sulfate compared with their control treatments. The highest root area on 6 and 16 September in all three cultivars was achieved by priming with zinc sulfate. Despite the decrease in root diameter of delay sowing date, priming treatments could increase root diameters compared with controls in each sowing date.

In order to evaluation of genetic variation and comparison of 8 populations of Iranian anises, a study was conducted in the research farm of University of Zanjan in randomized complete block design during 1392 and 1393. Evaluated traits were days to flowering, days to maturity, grain filling period, plant height, number of fertile umbels, umbelet numbers per umbel, grain yield, biological yield, harvest index and grain essential oil percentage. Combined analysis of variance showed significant differences between years and between studied populations, point of all traits except grain filling period. The highest coefficients of genetic and phenotypic variation were found in traits of grain yield, biological yield and grain essential oil percentage and the highest heritability in traits of grain essential oil percentage, biological yield, grain yield, umbelet numbers per umbel and plant height, respectively. Based on cluster analysis, 8 under studied populations were divided into three groups that the first group of populations were better than others in terms of important traits such as days to flowering, days to maturity, plant height, number of fertile umbels, grain yield and biological yield. The results showed that there has been a high diversity between anise populations and yield and essential oil percentage is able to increase by selection in anise populations. Also regarding to excellencey of Qazvin, Markazi and Sabzevar populations, selecting within them can be proposed to improve yield and essential oil percent.

The use of plant growth promoting rhizobacteria, is a solution to reduce the application of chemical fertilizers. In this research, first 51 rhizobacteria isolated from alfalfa rhizosphere, were screened from plant growth promoting point of view. According to the results of the screening of bacteria, 2 Rhizobium isolates, 2 Bacillus isolates and 4 Pseudomonas isolates were selected as superior strains to prepare the inoculums. To evaluate the effect of selected isolates on soybean growth indices, a completely randomized block design was carried out with 12 treatments and 3 replications. Treatments were included 4 Pseudomonas isolates, 2 Bacilli isolates and 2 Rhizobium isolates, mix of Bacillus, Rhizobium and Pseudomonas, control without Fertilizer and bacteria, half of fertilizer recommendation and Fertilizer recommendation. All Plant Growth Promoting Rhizobacteria treatments were accompany with Bradyrhizobium. The results indicated that bacteria inoculation significantly increased soybean growth indices, such shoot dry weight, root dry weight, root nodules, pods, seed weight, Fe, Zn, Mn, concentration of shoot, shoot nitrogen and phosphorus uptake compared to the control and the highest shoot Mn concentration was related to T8 treatment and the highest shoot N and P concentrations resulted from T5 (Bacillus), T8 (Rhizobium) and T1 (Pseudomonas) treatments. Generally, Pseudomonas bacteria were more effective than Bacillus and Rhizobium, to increase soybean growth indices and it can be attributed to high plant growth promoting properties of bacteria. According to the results, the usage of plant growth promoting rhizobacteria (PGPR), can decrease consumption of chemical fertilizers, especially N and P fertilizers. However, their use in field conditions requires further investigation.

This study was conducted to evaluate the effect of salinity and temperature on seed germination characteristics of lemon balm (Mellissa officinalis L.) in various temperatures of 20, 23, 25, 27, 30 and 32ºC and water potentials of 0, -0.2, -0.4, -0.6 and -0.8 MPa were used as treatments in Seed Laboratory, College of Agriculture and Natural Resources, University of Tehran in 2015. Data were analyzed using combined statistical design. Percentage of germination decreased as salinity increased at each level of temperature. Estimate of threshold point for salinity was -0.132 MPa. Segmented function was evaluated to describe cardinal temperatures. The base, optimum and ceiling temperatures of lemon balm were 17.30, 30.9 and 35ºC under optimum conditions of water potential, respectively. Response curve of the base temperature increased linearly from 17°C (control) to about 23°C (-0.8 MPa) by decreasing water potential. The base and optimum temperature and the biological time for germination were increased by increasing salinity. The results showed that Melissa officinalis L. is sensitive to salinity in germination stage.

In the present study, the effect of plant growth regulators on direct somatic embryogenesis and plant regeneration of two Iranian sunflower hybrids (Azargol and Farrokh) were examined. After the flowering, immature embryos ten day after pollination were used as explants. Immature embryos were surface sterilized and subsequently transferred to embryogenesis medium containing MS medium elements and B5 vitamins, 120 g/l sucrose and different combinations of plant growth regulators (BA in two levels,1 and 2 mg/l in combination with NAA or 2,4-D in three levels 0.1, 0.25 and 1 mg/l and 2,4-D in two levels, 0.33 and 1 mg/l. Analysis of variance showed significant differences between hybrids, hormones and hybrids×hormones interaction. The somatic embryos were first observed 10 days after culture on medium containing 120 g/l sucrose and a callus intermediate was not formed. Somatic embryos of two sunflower hybrids directly obtained on a medium supplemented with 2 mg/l BA and 0.25 mg/l NAA with more number and speed.