Crop Production
Year:2010 | Volume:3 | Issue:2|Papers Count:15

Seed reserves are controlled by genetic and environmental condition such as nutrition, temperature, drought stress and light intensity. Strong seedling will produce from seeds with high reserves. Therefore, in this work that conducted in pot, field(in Tabriz university) and lab(in Shahrood university of technology) experiments, effect of pre-anthesis nitrogen application and a drought stress during grain filling stage on seed carbohydrate and nitrogen reserves and seedling vigor from these seeds were investigated. Two barley (Hordeum vulgare L.) cultivars named Walfajr and Reihan affected by nitrogen and drought stress levels in a randomized complete block design as factorial split plot with three replications. Three levels of nitrogen (60, 120 and 180 kgha-1) and three irrigation levels (80-85, 55-65 and 35-45 percentage of field capacity) were applied at heading and 10 days after anthesis, respectively. Soil water was controlled by pot weighing and determination of soil moisture in pot and field experiments, respectively. Seed reserves including soluble sugar, starch and nitrogen and seedling vigor from these seeds with different reserves were evaluated. The high N application improved seed reserves. The mild drought stress treatment compared with the well water treatment increased the grain non structural carbohydrate and nitrogen and seed weight, but, these traits decreased by sever drought stress treatments. The grain protein enhanced by 1.3-3.3 % at drought stress treatments. The seeds that harvested from NN MD treatment had proper reserves, and germination rate, coleoptile length, root length and shoot weight in these seeds were higher than from other treatments. EC was low in seeds that obtained from NN and HN significantly. Seed germination rate was higher in Reihan, but, seed reserves in Walfajr were higher and seedling in Walfajr was stronger.

In order to study the yield and growth indices of spring safflower as double cropping, an experiment was carried out in 2007 at the research farm of faculty of agriculture, Yasouj University, Iran. The experiment was a factorial based on randomized complete block design with three replications. Factors included of combination of four sowing dates (May 16, June1, June 16 and July 2) and four cultivars (Arak 2811, Esfahan 14, IL111 and PI). Results showed that Esfahan 14, compared to other cultivars, had the highest grain and biological yields due to higher Leaf Area Index (LAI), Crop Growth Rate (CGR), Dry Matter (DM) and Net Assimilation Rate (NAR). Thus it might be suggested as appropriate cultivar for double cropping in Yasouj. Third sowing date produced the highest grain and biological yields relative to others. It appears that cultivars in third sowing date, due to grater LAI, probably had more radiation intercept and photosynthesis, so that had the grater CGR and DM and grater seed and biological yield. Finally, increasing of above mentioned indices resulted in grater seed and biological yield at third sowing date. Maximum NAR (10.1 gr m-2 leaf day-1) and LAI (2.76) were seen at third sowing date. Finally, with respect to the results, LAI, CGR and DM were the effective indices on seed yield of safflower cultivars.

To evaluate the effect interference of mustard on yield and yield components of canola, and observation competition difference of mustard in pot and field condition, experiments were conducted in 2006 and 2007 in the greenhouse and farm of College of Agriculture, Ramin Agricultural and Natural Resources University of Khouzestan, respectively. Pot experiment the factorial set of treatments was arranged within a completely randomized, and field experiment a split-plot design was arranged in a randomized complete block design with three replications. Treatments were various mustard densities in five levels (0, 1, 2, 3 and 5 plants pot equal with 0, 7, 14, 21 and 35 plants m-2 in field) and canola densities in three levels (10, 13 and 16 plants pot equal with 60, 80 and 100 plants m-2 in field). Result in pot condition indicated that increase in mustard density was caused to decrease all traits seed yield, pod number per plant, seed number per pod, and 1000-seed weight. While in field condition, except seed number per pod, and 1000- seed weight was significant on other traits, but increase density of canola at both conditions was caused to increase only seed yield. Interaction between different densities of mustard and canola in pot condition on seed number per pod, and in field condition seed yield and seed number per pod had significantly. In addition, curve of yield loss showed that the effect of interference different densities of mustard on seed yield of canola was differed in greenhouse and field condition. The seed yield most loss of canola was got in greenhouse from densities 10, 13 and 16 plants per pot and in field from densities 80, 60 and 100 plants m-2, respectively. This order was representative of difference competition in pot and field conditions.

This research was conducted to study the effects of different salinity levels and exposure times on grain yield and yield components in a green-house experiment at Gorgan University of Agricultural Science and Natural Resources during 2007- 2008 growing season. A factorial sand culture experiment with three completely randomized replications was used. Salinity levels were -0.002, -0.25, -0.50, -0.75 and -1 MPa (NaCl) and three salinity exposure time (throughout the growing season, from two-leaf to double ridge stage and from double ridge stage to maturity). Results indicated that effect of salinity, salinity exposure time and their interaction effect were significant for seed yield and spike number per plant. Effects of salinity and exposure time for number of aborted floret and number of grain per main stem spike were significant, but their interaction wasn’t significant. The highest and the lowest yield and spike number per plant obtained belonged to control and -1MPa throughout the growing season treatments. Yield and number of head per plant decreased along with increasing salinity severity and exposure time. Significant correlation was seen between yield and number of grain per plant (r=0.97) and grain weight (r=0.77).

Recently, biological fertilizers extensively recommended because of over application of chemical fertilizer and their effects on environment and production resources. In order to study the effect of inoculate phosphate solubilization microorganisms (PSM) and plant growth promoting rhizobacteria (PGPR) on nutrient use efficiency in corn [Zea mays (L.) cv. SC 604] an experiment was conducted in 2007. Experiment laid out as split plot based on randomized complete block design with three replications. Three levels of manures (consisted of 20 Mg.ha-1 farmyard manure, 15 Mg.ha-1 green manure and check or without any manures) as main plots and eight levels of biofertilizers (consisted of 1-NPK or conventional fertilizer application; 2-NPK +PSM+PGPR; 3-NP50%K+PSM+PGPR,4-N50%PK+PSM+PGPR; 5-N50%P50%K+PSM+ PGPR; 6-PK+PGPR; 7-NK+PSM and 8-PSM+PGPR) as sub plots were treatments. Results showed that, using of PSM and PGPR in addition to conventional fertilizer applications (NPK) could improve the agronomic efficiency, nutrient use efficiency and relative agronomic efficiency. According to results, farmyard manure, green manure, PGPR and PSM application significantly improved the nutrient use efficiency by 37.2% and 82.1% compared to control. Also, nitrogen recovery in green manure and check plots enhanced with adding of biological fertilizer compared to lack of these biofertilizers by 55.2% and 17.6%, respectively.

In order to study of nitrogen absorb and use efficiency of wheat (Triticum aestivum) and wild oat (Avena fatua) at vegetative growth stage, a factorial experiment was conducted based on completely randomized block design with three replications in research greenhouse of faculty of agriculture, at Ferdowsi University of Mashhad in 2008. The first factor was competition between wild oat densities of 0, 2, 4, 6 and 8 plants per pot) and wheat (density of 8 plants per pot and the second factor was five different levels of nitrogen (1, 4, 8, 12 and 16 mM) The experiment was finished at the end of vegetative growth stage of wheat and data were analyzed using regression analysis. Results showed that nitrogen percentage (NP), nitrogen absorb efficiency (NAE) and nitrogen use efficiency NUE) in wheat and wild oat were affected by experimental factors. Nitrogen content increased in wheat as well as wild oat when nitrogen level increased to reach to asymptote at 8 mM nitrogen. NP was decreased in wheat (except at 1mM nitrogen) when weed density increased, but was not affected in wild oat by wheat competition. NAE of wheat was decreased exponentially in all weed densities and was not affected by wild oat competition. NAE of wild oat followed a positive significant linear relationship with adding of density. It indicated the growth up of nitrogen absorb of wild oat in competition situation. NUE was similarly affected in wheat as well as wild oat.

The first step in identification of genes which control traits in stress and no stress conditions is localization of chromosomal related to traits. In order to locate the genes controlling drought resistance and screening quantitative indices of drought resistance in wheat, substitution line series of Hope into the genetic background of Chinese Spring (CS) were tested in a randomized complete block design with three replications under two irrigated and water stress conditions. Based on the potential (Yp) and stress (Ys) grain yield, criteria of drought tolerance such as: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), stress susceptibility index (SI) and stress tolerance index (STI) were estimated. The results exhibited high significant differences among the lines for traits studied indicating the presence of genetic variation and possibility of determination of the genes controlling these traits on the related chromosomes. The results of mean comparison showed that most of the genes controlling yield and yield components in the non-irrigated conditions are located on the chromosomes 6A, 7A, 3D, 2B, 7D and 7B. The results of correlation analysis between indices، potential and stress yield showed that the most suitable criteria for screening substitution lines were MP, GMP and STI. Evaluation of biplot and three dimensional plots indicated that most of the genes controlling MP, GMP and STI are located on chromosomes 1A, 6B, 4D, 7A, 7B, 7D, 6A, 2B and 3D. To determine the genetic distance and to group the substitution lines, cluster analysis showed that the substitution lines 6A, 7A, 3D, 4D, 7D, 7B, 2B and Hope were in one group supporting the results of 3-D and biplot that they can be used for improvement of drought tolerance in Wheat.

Low temperature (LT) acclimation, phenological development and vernalization requirement are known to influence the expression of frost tolerance (FT) in winter cereals. A phenotypic study was undertaken to determine the interrelationship between developmental stages and FT in hardy winter wheat and rye cultivars acclimated under field condition in the cold and temperate regions of Iran. Winter wheat Norstar (Triticum aestivum L.) and winter Puma rye (Secale cereale L.) with long vernalization requirements were planted at the second decade of October in 2008 at Karaj and Zanjan as temperate and cold regions, respectively. Plant development (morphological stage of shoot apex) ,vernalization requirement (days to heading and final leaf number) and FT (survival of plants exposed to freezing conditions) were evaluated during the autumn and winter seasons in 2008-09. Furthermore, the Fv/Fm ratio, the quantum efficiency of photosystem II and chlorophyll content of upper fully expanded leaves were measured at the early stage of reproductive growth in Karaj. Result showed that in both species, FT increased during the autumn in 2008 and the maximum FT in the both regions was achieved during the second decade of January 2009, which was about the same time as vernalization fulfillment occurred. Puma rye plants acclimated in Zanjan showed the highly significant level of FT (~-24oC) in March in comparison to Norstar wheat (LT50= -17oC). A highly significant decrease (P<0.01) in final leaf number (FLN) and day to heading was observed with increase of cold acclimation periods in both species and regions. However, the rate of decrease in FLN was rapid in Puma rye compared to Norstar wheat. The delay in the phenological development of Norstar winter wheat was pparent in plants grown in Zanjan compared to ones grown in Karaj. A constant trend of Fv/Fm was observed during the measuring periods, though chlorophyll content was significantly (P<0.01) increased with the initiation of reproductive stage in both species. From these results it is concluded that the level and duration of expression of FT is determined by the acclimation emperature of locations and phenological traits such as vernalization requirement and flowering time in cereals.

Orchard grass (Dactylis glomerata), a pasture and forage grass, has wide genetic distribution in Iran. Evolution of germplasm and selection of suitable genotypes is the first step for developing adaptable synthetic varieties. In order to investigate production potential, variation and genetic similarity of Iranian Orchard grass genotypes, an experiment was conducted using clonally propagated materials. Genotypes were evaluated for agronomic, phenological and morphological characters under a randomized complete block design during 2005 and 2006. Results showed that there are significant differences between genotypes for all of the traits indicating a broad genetic diversity in this germplasem. Genotypic coefficients of variability for seed and forage yield were highest while the lowest belonged to phenological traits, plant height and crown diameter. The highest estimates of heritability were observed for days to headings, days to pollination and plant height, while the lowest was for crown diameter. Applying cluster analysis on the studied attributes, three groups were obtained. Regarding all measured characters the least and the most similar accessions were identified to be used in the further breeding projects. Finally, on the basis of the results it can be concluded that clonally evaluations trails can be useful to estimate genetic variation and selection of appropriate parents for conducting advanced breeding programs.

Canola has industrial applications as well as edible usage. In regard to 15.8 kg oil per capita usage and vast oil importing, cultivation development of oil seeds is a major issue. This study was performed to determine the best sowing date and cultivars for canola as means of seed yield and oil percent improvement in Dehloran region of Elam province. 25 treatments were used in a split plot experiment based on RCBD design with 4 replications. Five sowing dates (Oct 18th, Oct 28th, Nov 7th, Nov 17th and Nov 27th) were applied as main-plots and five cultivars (Hyola308, Option500, PF, RGS003 and Hyola408) were used as subplots. Sowing date has significant effect on morphological and physiological traits except in the 1000-kernel seed weight. Morphological and physiological characteristics and yield components were significantly different among cultivars. The sowing date and cultivar interaction was significant for all traits except yield and number of pods on main branch. Based on the results maximum and minimum seed yield produced by Hyola308 (2737 kg/ha) and PF (2173 kg/ha), respectively. For sowing dates, October 18th and November 27th had the most and the least yield production for all cultivars, respectively. With regard to the results, the suitable sowing date, effectively improves seed yield in canola. It can be concluded that date from October 17th till November 6th could be recommended as an appropriate sowing date for Dehloran region.

This experiment was conducted to screening phenolic acids in root exudates of three rice cultivars (Neda, Taichung and Sepidrood) by high performance liquid chromatography (HPLC) method and to evaluate allelopathic potential of these cultivars on growth characteristics of barnyard grass weed. The experiment was arranged in factorial based on completely randomized design with four replications in greenhouse and laboratory conditions at Sari Agricultural Sciences and Natural Resources University during 2007. The results of ANOVA indicated that all treatments and interactions had significant effect at 0.01 levels on all studied traits.In terms of more studied traits, Taichung (root exudates) had the highest amounts compared to other cultivars. Accordingly, Taichung by 40.60% and Sepidrood by 0.60% had the highest and lowest inhibitory on root lengths of barnyardgrass, respectively. In terms of dry weights, Taichung and Sepidrood had the highest and minimum effect with 29.60 and 2.60 inhibitory percentages, respectively. Root exudates of Thaichung with 50.90% and 31.90% had the highest inhibitory effects on germination rate and percentage of barnyard grass seeds, respectively. In terms of physiological traits such as chlorophyll and nitrogen contents the highest amount of inhibition were related to Neda (with 58.20% and 43.80%, respectively) and the lowest amounts were recorded for Sepidrood (with 1.70% and 11.30%, respectively). Root exudates of all cultivars were also analyzed by HPLC method. The results showed that the highest phenolic contents (6.085 mg/l) were related to root exudates of Taichung and the lowest amounts (0.201) were belonged to Neda.

To evaluate the effects of soil fertilizing treatments on agro morphological traits and mucilage of Isabgol, a glasshouse experiment was conducted in College of Agronomy and Animal Sciences, University of Tehran. The experiment was conducted as a factorial based on complete randomized block design with three replications. In this study, the effects of soil fertilizing treatments including control, two level of chemical fertilizer (N and P), two level of cattle manure (dairy cow manure), two level of combined use of cattle manure and chemical fertilizer and Barvar Phosphate biofertilizer (BPB) inoculation were investigated. The results showed that fertilizing treatments revealed significantly higher yield, yield components, mucilage and mucilage yield than control. The effect of BPB on the majority of above mentioned traits were significant, while mucilage percentage was not affected by BPB. Cattle manure and combined use of cattle manure and chemical fertilizer were more effective than chemical fertilizer and significantly increased grain yield and mucilage. The highest grain yield (0.916 gr/plant) was obtained from N20P10+20 ton/ha cattle manure with BPB inoculation.

Jimsonweed (Datura stramonium L.) is an important weed in bean fields in Iran. In order to investigate the effect of density and relative time of emergence of Jimsonweed on yield and yield components of chitti bean, a field study based on factorial experiment was conducted at farm bean Research National Station in Khomein in 2006. Treatments were chosen to provide four different weed densities (4, 8, 12 and 16 plant m-1) and three time of weed emergence (with crop emergence, in first trifoliate leaf stage and third trifoliate leaf stage of bean) with a weed free treatment as control. Results showed that the effect of jimsonweed interference on bean yield and yield components was significant. The yield of bean was more affected by relative time of Jimson weed emergence than its density and decreased 52%, 47% and 23% in 1st, 2nd and 3rd time of weed emergence respectively in highest level of density. The number of pod per plant and 100-seed weight of bean were the most important yield components which be decreased by jimsonweed competition, but the number of seeds per pod was not affected. The effect of interaction between experimental factors was significant on bean yield. The effect of jimsonweed density on bean yield decreased when the relative time of weed emergence increased, so effect of weed density on bean yield in 3rd time of emergence was not significant. The results demonstrated the high sensitivity of bean yield to early competition of jimson weed even at low densities.

Using crop simulation models is an efficient complement to experimental research. Crop models can also be helpful with respect to decision-making in sustainable farming system. This study was done to estimate genetic coefficients and evaluate performanced DSSAT in prediction of development, growth and yield in wheat. Data from various field experiments for four wheat cultivars Koohdasht, Shiroudi, Tajan and Zagros were used. After estimation of genetic parameters, the model ability were evaluated in simulation of phonological development in days to an thesis, days to maturity, dry matter production at anthesis and physiological maturity, leaf area index at anthesis, accumulation of nitrogen at anthesis and maturity and grain yield. Root Mean Square Error (RMSE) for grain yield was equal to 668 kg. ha-1 which was 18.2 percent of the mean yield. Model predictions were appropriate for other crop development and growth characteristics. Therefore, the model can be used for simulation these cultivars.

Cold is one of the most important abiotic stresses in some regions of Iran. To Investigate of some tolerance related traits to cold condition, 22 bread wheat genotypes planted in Ardabil region in 1980. After plants passed winter cold condition (135 freezing days), cell membrane stability, chlorophyll content of leaf and crown depth and grain yield of genotypes were measured. ANOVA analysis showed significant differences between genotypes for grain yield, cell membrane stability and chlorophyll content of leaf at 5%. While there was none significant differences between genotypes for crown depth Mean comparison showed that , Aug//gt/…, Navid, C-73-8, sardari and C-70-3 genotypes with 3.52, 3.41, 3.34, 3.26 and 3.24 ton/ha respectively had the highest and 4213 genotype with 1.59 tn/ha had the least grain yield in experiment condition. Correlation coefficients showed negative significant correlation between grain yield and cell membrane Stability, and positive correlation between grain yield and chlorophyll content of leaf. Overall it seems these methods can be used as simple and quick tools for evaluating and screening wheat genotypes in winter cold condition.