جستجوی مقالات مرتبط با کلیدواژه « آنالیز رشد » در نشریات گروه « کشاورزی »

Deficit irrigation offers a solution for optimizing crop production under water stress conditions, albeit with an initial reduction in yield per unit area. Employing deficit irrigation aids in farm management in scenarios where land availability isn’t constrained, enabling the determination of optimal cultivation patterns while conserving water consumption. However, deficit irrigation may influence plant growth and development by inducing drought stress. Due to several capabilities, quinoa shows resistance to solar radiation, temperature, water availability, and atmospheric CO2 concentration, which makes it possible to cultivate it in different agricultural areas. Quinoa also has a great capacity for cultivation in dry and low-water soils. Although growth analysis sometimes provides valuable clues, it does not provide any physicochemical information related to the environmental reactions of plants; in other words, the main benefit of many quantities involved in growth analysis is to provide an accurate estimate of the ability and efficiency of the plant in the community at certain time intervals. In general, growth analysis evaluates the system based on the results of physiological manifestations. The purpose of this research was to evaluate the physiological growth analyses of three quinoa cultivars under different moisture levels in summer and spring planting dates in the South Khorasan region.

To evaluate the physiological traits of three quinoa cultivars under deficit irrigation conditions, four separate experiments were conducted using a factorial layout based on a randomized complete block design. These experiments included three replications and were carried out in two regions (Birjand and Sarbisheh) during two planting dates (March and July) in 2018-2019. The experimental factors consisted of five moisture levels (ranging from 25% to 125% of crop water requirement) and three quinoa cultivars (Titicaca, Giza1, and Redcarina). To compare the cultivars and assess the impact of humidity levels, several physiological indices—such as leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), and net assimilation rate (NAR)—were studied. Regression curves were fitted to the data from all four experiments separately, and separate analyses of variance were also performed for each sampling time.

The trend of changes in the leaf area index (LAI) showed that the time needed to reach the maximum LAI was observed between 106 to 107 days after emergence in March and between 73 to 76 days after emergence in July in Birjand, respectively. In Sarbisheh, the maximum LAI was observed on day 104 after emergence in March and between 65 to 72 days after emergence in July. In March, in both studied areas, Redcarina had the highest LAI values (4.5 in Birjand and 6.7 in Sarbisheh), along with the maximum crop growth rate (CGR) of 17.93 g m-2 day-1 in Birjand and 20.63 g m-2 day-1 in Sarbisheh. Conversely, in July, Giza1 exhibited the highest LAI (6.4 in Birjand and 6 in Sarbisheh), along with the maximum CGR of 19.32 g m-2 day-1 in Birjand and 18.11 g m-2 day-1 in Sarbisheh. Additionally, the highest relative growth rate (RGR) and net assimilation rate (NAR) at the beginning of the growing season in March were observed for Redcarina, while in July, Giza1 demonstrated the highest RGR and NAR in both studied areas. Considering the effect of humidity levels, the highest levels of LAI, CGR, RGR, and NAR indices were observed at the 125% water requirement level. Specifically, the maximum LAI values in March (in Sarbisheh and Birjand) and August (in Sarbisheh and Birjand) were 8.2, 5.3, 6.5, and 7.2, respectively. The maximum CGR values were 28.78, 23.56, 22.96, and 26.18 g m-2 day-1, respectively. Furthermore, the highest RGR at the beginning of the growing season ranged from 0.189 to 0.214 g g-1 day-1, and the highest NAR at the beginning of the growing season ranged from 6.16 to 10.22 g m-2 day-1. Conversely, the lowest values of these indices were observed at the 25% water requirement level.

Overall, Redcarina, cultivated in March, and Giza1, cultivated in July, exhibited the most favorable growth analysis indices and grain yield compared to other cultivars. Additionally, deficit irrigation resulted in a decrease in all of these indices and grain yield.

Potato plays an important role in global food security and it growth and tuber yield are influenced by many biotic and abiotic stresses, such as drought and low or high temperatures. Potato in Khuzestan province is facing unfavorable weather conditions, especially high temperature. Humic acid and amino acid, as well-known biostimulants, can directly or indirectly influence on plant growth and yield and significantly mitigates the injuries caused by abiotic stresses. In some studies, the use of humic acid has been reported increase root length, improve nutrient uptake, and increase chlorophyll synthesis. Amino acids in potato plant increase natural resistance to stresses. It seems that biostimulants and some nutrition elements can be applied as a strategy to reduce the negative effects of high temperatures. Therefore, this study was conducted to evaluate the effect of plant growth biostimulants on growth indices, yield and yield components of potato cultivars in Khuzestan region.

This research was conducted in two studies. First study was carried out as a factorial experiment in a randomized complete block design (RCBD) with two factors including 16 treatments in three replications at Behbahan Agricultural Research Station in 2019-2020. The first factor was application of plant growth biostimulants at eight levels: control (application of chemical fertilizers according to soil test), humic acid, free amino acid (L), amino acid-Zn, amino acid-K, amino acid-Ca, amino acid-K-Ca and application of all studied biostimulants (except free amino acid). The second factor consisted of two potato cultivars: 'Ottawa and Sante'. In the second study, growth analysis was done in a split plot factorial based on RCBD with three replications. Main plot consisted of five sampling periods with 15 days intervals. Sub plot consisted of combination of eight plants growth biostimulants and two cultivars of potato as factorial. Tubers were planted at mid January. One week before harvesting haulms were defoliated and tubers were harvested at mid May. Humic acid was used as fertigation at 10 kg.ha-1 in the early stages of growth. Foliar application of amino acid, amino acid-Zn was done at two stages, tuber initiation and the beginning of tuber bulking. Foliar application of amino acid-K, amino acid-Ca was done at two stages, the beginning and middle of tuber bulking. Amino acid and amino acid-nutritional element were done at a concentration of 0.5 %. Varince analysis were done by MSTATC statistical software and meanes were compared using Duncan’s multiple test range at the 5% level.

The results showed that in two cultivars, application of all studied biostimulants (except free amino acid) significantly increased tuber yield compared with control. In Sante cultivar, the highest yield was dedicated in the treatment of combined, and the yield of this treatment was significantly higher than the yield of  alone application of these substances. In Ottawa cultivar, the highest yield was achieved by application of combined biostimulants, but the differences of tuber yield among this treatment and treatments of amino acid-K, amino acid-Ca and amino acid-K-Ca and humic acid were not significant. The results of growth analysis showed, in the most sampling periods, the highest tuber and crop growth rate were recorded in the combined treatment. Therefore the highest tuber yield was observed in this treatment. In the first and second sampling periods, application of humic acid or amino acid-Zn were more effective than other treatments. But, in the third and fourth sampling periods, treatments of amino acid-K, amino acid-Ca were more effective in comparision to alone of these substances. In different sampling periods, tuber and crop growth rate in Ottawa cultivar was significantly higher than Sante cultivar.

According to results, in Sante cultivar, the combined treatment of plant growth biostimulants produced the highest yield in comparision to any individuals of these substances. Therefore, use of humic acid as fertigation in the early stages of growth and foliar application of amino acid- Zn at two stages tuber initiation and the beginning of tuber growth and amino acid-K-Ca at two stages the beginning and middle of tuber growth, are recommended. In Ottawa cultivar, the differences of tuber yield among treatment of combined application of growth biostimulants, amino acid-K, amino acid-Ca and amino acid-K-Ca and humic acid were not significant. Therefore, based on the finding of the present study, it could be concluded that treatments of amino acid-K, amino acid-Ca or humic acid may be an effective growth biostimulants for improving yield of Ottawa cultivar.

Higher plants are self-supporting organisms that can build their organic molecular compounds from mineral nutrients absorbed from the environment. Therefore, sufficient access to the optimum level of nutrients in the environment is very important. The main objective of this study was to determine the nutritional requirements of different ecotypes of henna (Lowsonia inermis L.) as a medicinal- industrial plant (Bam, Shahdad and Roodbar) based on nitrogen, phosphorus and potassium (N: K: P, 0: 0: 0, 100: 50: 50 , 200: 100: 100, 300: 200: 150 Kg ha-1) in Kerman climatological condition. The results showed that the interaction of ecotype × fertilizer was significant only for leaf and total dry yield at the probability level of 5%. Mean comparison of this interaction showed that all three examined ecotypes had the highest leaf dry yield in the fertilizer ratio of 300: 200: 150 and did not have a significant difference with each other. The effect of ecotype was significant only on net photosynthesis and stomatal conductance and the highest mean of these traits belonged to the Shahdad ecotype. In this study, the simple effect of fertilizer treatment was significant for all traits studied except for specific leaf area and specific leaf weight. The highest mean of leaf area index, net photosynthesis and stomatal conductance was recorded for the 300: 200: 150 fertilizer ratio, while in the case of transpiration rate and crop growth rate there was no significant difference between 300: 200: 150 and 200: 100: 100 combination treatments. In general, in order to achieve maximum crop growth rate and suitable leaf area index to produce the highest leaf dry yield of henna in Shahdad and Roodbar ecotypes, the fertilizer ratio of 300: 200: 150, and in the Bam ecotype, the fertilizer ratio of 200: 100: 100 under similar conditions of this study seems to be appropriate.

To analyze the growth, it is necessary to access to accurate and well-arranged data obtained from measuring leaf area and dry matter accumulation. The purpose of this study was to evaluate different nonlinear regression models to study the trend of changes in leaf area index and dry matter production and to estimate the parameters related to the growth analysis. The experiment was conducted on faba bean "cv. Barakat" with a split-plot design in a randomized complete block design with three planting dates and four densities in four replications. In this study, the beta and logistic models were fitted to the leaf surface data and the beta, Gompertz and logistic models to dry matter production. AICc benchmark showed that the beta model was fitted to the leaf surface data the better than the logistic model. LAImax in different densities varied between 2.3 to 5.3, tm between 131.9 and 144.2, and te between 158.7 and 163.5 day after planting. AICc benchmark showed that the beta model was fitted to the dry matter accumulation data the better than the Gompertz and logistic models. Wmax in different densities varied between 725.1 and 1484.3 gr/m2, tm between 138.3 and 146.4 and te between 162.60 and 179.0 days after planting. Grain yield varied from 231 to 2744 gr/m2, and with increasing density in each planting date, grain yield showed the increased trend. The results showed that yield changes were directly affected by maximum leaf area index, maximum dry matter accumulation and crop growth rate.

In order to evaluate different irrigation amounts and salicylic acid spraying and determination of principal components in water use efficiency of sesame (Sesamum indicum L.), maize (Zea mays L.) and common bean (Phaseolus vulgaris L.), a split plots experiment based on RCBD design with three replications was conducted in 2014-2015 growing seasons, in Ferdowsi University of Mashhad, Iran. Irrigation levels (50 and 100% of water requirement) and application and non-application of salicylic acid assigned to main and sub plots, respectively. The result showed that in sesame and maize, the highest seed yield obtained in conditions of salicylic acid application. Variables analyzed to 3 factors in sesame and 2 factors in maize and bean. In sesame, first factor included variables of dry matter yield, plant height, leaf erea index and soil phosphorous, variables of seed yield, seed weight per plant, crop growth rate and water use efficiency were in second factor and variables of EC, soil nitrogen and pH had the highest load in third factor. In maize, variables of seed yield, dry matter yield, seed weight per plant, plant height, crop growth rate, leaf erea index and water use efficiency were on first factor and variables of soil nitrogen, EC, pH and soil phosphorous had the highest load in second factor. In bean, variables of seed yield, dry matter yield, seed weight per plant, crop growth rate, soil nitrogen and phosphorous, EC and water use efficiency were in first factor and second factor included variables of leaf erea index, plant height and soil pH. In general, in all three plants, water use efficiency and effective variables in seed yield were in same factor, therefore it seems that any change in these variables will result in a direct change in water use efficiency.

The pattern of dry matter accumulation and crop growth rate are important characteristics affecting optimal crop production. Plant nutrition has a significant impact on plant growth pattern. In this research, the effect of foliar application of Zn in the form of ZnSO4 and synthetic complexes of methionine-Zn (Zn-Met) and lysine-Zn (Zn-Lys) on pattern of dry matter accumulation, crop growth rate, and other growth indicators of onion (Allium cepa L. cv. Primavera) was evaluated. Foliar Zn application at a concentration of 0.5 % was performed at two stages: once at the early rapid vegetative growth stage (at stage of leaf blade growth), and the other at the early bulbing. The results indicated that, at all fertilizer treatments, the slow growth period lasted 128 days after seed germination followed by the rapid growth period. The maximum leaf area index (LAI) (3.44), bulb growth rate (31.30 g m-2 day-1), crop growth rate (40.70 g m-2 day-1), relative growth rate (0.0966 g g-1 day-1) and total biomass was obtained at the Zn-Lys treatment. For this reason, the highest total biomass (14.87 kg m-2) belonged to this treatment. Foliar application of Zn treatments was ineffective on the bulbing time. Among different treatments, the pattern of dry matter accumulation showed that Zn-Lys complex resulted in significant increase of plant dry mass (33% over the control treatment), and this trend continued until the end of the growing season. According to the results, foliar spray of Zn-Lys complex affected the growth pattern of onion and thereby resulted in significant improvement of dry matter accumulation, LAI, bulb growth rate, and crop growth rate. The highest total biomass was also produced in the Zn-Lys treatment. Also, Zn-Met complex significantly increased total biomass and blub quality but zinc sulfate only significantly increased zinc concentration in onion bulb. According to the results of this research, foliar spray of Zn-Lys complex is recommended for improving onion yield and quality in zinc deficient calcareous soils.

Priming is one of the most common methods of improving seed quality, which significantly affects their storability. Seed priming is a seed treatment that allows imbibition and activation of the initial metabolic events associated with seed germination, but prevents radicle emergence and growth. In other words, phase one and two of seed water imbibition curve are passed, but seeds do not enter the third phase of water uptake. Then seeds are dried back to their original water content. Seed priming is a pre-sowing strategy for influencing seed germination and seedling development by modulating pre-germination metabolic activity prior to emergence of the radicle and generally enhances germination rate and plant performance. Naturally, when speed and percentage emergence of germinating seeds are being high, growing sources like light, water and nutrient will be more used. Another factor that can affect the seed germination and seedling establishment is the seed size. As generally known, among producing factors, seed as the first consumer store, plays an important role in the transfer of genetic characters and improvement of qualitative and quantitative traits of production. One of the most important factors in maximizing crop yield is planting high quality seed. Seed size is an important physical indicator of seed quality that affects vegetative growth and is frequently related to yield, market grade factors and harvest efficiency. In the present paper, effects of different pre-sowing treatments and seed size on physiological growth indices and bulb dry yield of onion cultivars were investigated. In order to determine the response of physiological growth indices and bulb dry yield of onion to priming and seed size, a field experiment was conducted in 2012-2013 cropping season at Agriculture and Natural Resources Research Center of East, Azarbayjan, Iran. This experiment was a factorial experiment based on a randomized complete block design with three replications. Experiment treatments included priminig at four levels: hydropriming, osmopriming (in %2KNO3), priminig with falomin amino acid (in 2%) and control (without priming). Seed samples of the two cultivars were sieved by slotted screens and placed into three groups of seed diameter size: small, medium and large and cultivars at two levels: Red Azarshahr and Zarghun. The physiological growth indices such as total dry matter, leaf area index, crop growth rate, net assimilation rate, bulb growth rate and bulb fresh and dry yield were studied. Results of field experiment showed that seed priming improved growth indices such as dry matter accumulation (DMA), crop growth rate (CGR), net assimilation rate (NAR), relative growth rate (RGR), bulb growth rate (BGR) and leaf aria index (LAI) in both cultivars. The highest bulb fresh, dry yield and dry matter percentage (54400, 6800 kg/ha and11/80 %) belonged to priminig with folammine amino acid, respectively. The results of growth analysis indicated that the maximum and minimum growth indices values were obtained from large and small seeds, respectively. Mean comparison showed that the highest bulb fresh yield (53.26 ton/ha), bulb dry yield (9.95 ton/ha) and bulb dry matter (11.47 %) were achieved from large seeds. Mean comparison indicated that the highest bulb fresh yield (43.40 ton/ha), bulb dry yield (5.43 ton/ha) and bulb dry matter (11.47 %) were observed in Red Azarshahr. Seed priming treatments improved bulb fresh and dry yield, total dry matter, leaf area index, crop growth rate, bulb growth rate, relative growth rate and net assimilation rate as compared to the unprimed. Among the treatments, seed priming with Falomin Amino Acid 2% was more effective than the potassium nitrite 2% and hydropriming. Large seed size significantly increased the bulb fresh and dry yield and physiological growth indices. The highest bulb fresh and dry yield, total dry matter, leaf area index, crop growth rate, bulb growth rate, relative growth rate and net assimilation rate were achieved in larger seeds compared to other sizes. Accordingly, the importance of seed priming and grading seeds were obvious in this study, so seed priming with Falomin Amino Acid 2% and large seed size should be used for onion planting in order to insure high bulb fresh and dry yield and physiological growth indices of onion. Nevertheless, seed priming and seed size improved bulb fresh, and dry yield and physiological growth indices of onion cultivars were attributed to rapid seedling emergence and establishment, and consequently the optimum use of light, soil moisture and nutrients by the plants developed from the primed seeds and seed size. Therefore priming with falomin Amino Acid 2% and large seeds are recommended in onion planting for the places with the same environmental conditions of this experiment.

The present study intended to investigate the effect of different doses of Humic Magnesium Chelate and Gibberellin on cowpea’s growth trend and production components under field conditions in Shadegan in summer 2014. To this end, a factorial experiment in a randomized complete block design with three replications was conducted. The first factor included Humic Magnesium Chelate at three levels (0, 200 & 400 ml.h) and the second factor included Gibberellin at three levels (0, 150 & 300 ppm). The results indicated that spraying the plants with Humic Magnesium Chelate 400 ml.h and Gibberellin 300 ppm increased leaf Area Index (LAI) and Total Dry Weight (TDW). Whereas, in terms of Crop Growth Rate (CGR), spraying with Humic Magnesium Chelate 200 ml.h and Gibberellin150 ppm increased Regular Growth Rate (RGR) and Net Assimilation Rate (NAR). According to the results of ANOVA, there was a significant difference between different levels of Humic Magnesium Chelate in grain yield %5 probabilities Level. The difference between the different levels of Gibberellin, grain yield was significant at the 1% level. As well as the interaction between hormones, grain yield was significant at the 1% level. Furthermore, the highest grain yield was associated with the treatment of Humic Magnesium Chelate 200 ml.h and Gibberellin 150 ppm by 2,720 kg.ha; on the contrary, the lowest grain yield was observed in the control treatment by 1.950 kg.ha. To conclude, the results of the current research showed that the effect of Gibberellin treatment was higher on different doses of measured traits than Humic Magnesium Chelate treatment; and the application of Humic Magnesium Chelate 200 ml.h and Gibberellin 150 ppm was more effective on grain yield, yield components and physiological indices in comparison to the consumption of the higher concentration doses.

In order to investigate the impact of the sowing date on yield, yield components and physiological growth indices of grain maize (Zea mays L.) cultivars, a field experiment was conducted at the Faculty of Agriculture of the University of Lorestan in 2011 as a randomized complete block design with factorial arrangement of treatments and three replications. Treatments consisted of two sowing dates (21st May and 13th June) and six maize cultivars, namely T.V.C.767 and S.C.704 from a late maturing group, cultivars T N.S640 and Maxima from a mid maturing group, and cultivars Koppany and D.C.370 from early maturing group. Results indicated that the main effects of the experimental factors were statistically significant in terms of 1000-kernel weight, number of kernels per ear, number of kernels per row, number of rows per ear and harvest index. The interaction between sowing date and cultivar was only significant in the case of biological and grain yields, ear length and plant height. In the first sowing date the highest and lowest grain yields belonged to cultivars S.C.704 and D.C370 (12.7 and 7.5 t ha-1, respectively). In the second sowing date, N.S.640 from mid maturing group was ranked first in this regard (13.37 t ha-1). Higher grain yield in S.C704 and N.S640 compared to other cultivars, could be attributed to their higher leaf area index, leaf area index duration and crop growth rate. In total, planting late maturing group cultivars is not recommended for the second sowing date.

In order to study phenology, some growth indices and qualitative and quantitative characteristics of potato cultivars (Savalan, Sante and Cozima) an experiment was conducted for one year (2010-2011) at Behbahan Agriculture Research Station. The experimental design was randomized complete block design with three treatments and three replications. Tubers were planted at mid January 2010 and were harvested at mid May 2011. The results indicated that the yield of potato in Khouzestan province is lower than that in temperate regions due to the long sprout development stage and high temperature during the tuber bulking stage. The duration of the vegetative stage was short and the maturation stage was not observed. The haulm and tuber growth rate increased during the early season while reached a maximum value, following decline in the late season. The tuber and crop growth rate of Savalan cultivar (19.4 and 21.72 g m-2 day-1 respectively) was higher than other cultivars. Therefore, this cultivar produced the highest yield of tuber dry weight (4.20 t ha-1). The maximum of relative growth rate (0.598 g g-1 day-1) and maximum of tuber growth rate (0.320 g g-1 day-1) belong to Savalan and Cozima cultivars respectively. Cozima cultivar produced the highest total and marketable yield (19.91 and 18.38 t ha-1 respectively). In regard to, total and marketable yield the difference between Cozima and Savalan cultivars was not significant. Savalan cultivar produced the highest tuber dry weight percentage (22.38).

The yield of chickpea in Iran is low in comparison with other countries. One of the most important effective factors, is no application of optimal plant density and chickpea cultivars difference in response to plant density. In order to investigate the effect of plant density on yield and some physiological indices of chickpea cultivars, this experiment was conducted as factorial based on randomized complete blocks design with three densities 25, 35 and 45 plants in m-2 and three chickpea cultivars Jam, ILC-482 and Kaka at three replications at the research farm of Agriculture College of MohagheghArdabili University. The highest grain yield and the total dry matter accumulation in m-2 belonged to Kaka cultivar treatment combination in density 45 plants inm-2 and the lowest to density 25 plants in m-2 to Jam cultivar. The trend of crop growth rate and relative growth rate was similar to total dry matter. The results showed that plant density had significant effect on 100-grainweight, grains number per pod, pods number per plant, grains number per plant and grain yield .The highest grain yield was produced in Kaka cultivar with density 45 plants in m-2 and the lowest in density 25 plants in m-2 in Jam cultivar. So, it could be suggested that in order to increase the grain yield, total dry matter accumulation and the other physiological indices such as crop growth rate and relative growth rate, Kaka cultivar should be applied at density 45 plants in m-2.

In order to investigate the effects of supplementary calcium chloride and potassium nitrate on proline, protein content, chlorophyll and growth of Ammi (Carum copticum L.) under different salinity levels and nutrient solutions (NS), a RCBD design with factorial arrangement was conducted at the Agriculture Research Field, Vali-e-Asr University of Rafsanjan, during September 2009. The treatments were three levels of salinity (0, 50 and 100 mMol) and five different nutrition solutions including: Control: Hoagland solution only (N1); Hoagland solution plus 20 mM CaCl2 in nutrition solution (N2); Hoagland solution plus 20 mM CaCl2 as spray (N3); Hoagland solution plus 20 mM KNO3 in nutrition solution (N4) and Hoagland solution plus 20 mM KNO3 as spray (N5). Results showed that proline content was significantly affected by salinity and the type of nutrient solution and their interactions. Increasing salinity, especially at 100 Mmol NaCl, significantly reduced chlorophyll a,b and total chlorophyll. Chlorophyll a, b and total chlorophyll content were not significantly affected by the type of nutrition solution. The highest and lowest protein content were observed by control and 100 Mm NaCl treatments respectively. The type of nutrient solution also influenced protein content. The highest and lowest protein contents were related to N3 and N5, respectively. Total dry weight and stem dry weight were significantly reduced by salinity while root dry weight was not affected by salinity. The highest leaf area was achieved on control and nutrition solution N5. Generally, it is concluded that Ammi could tolerate salinity up to 50 mMol NaCl and leaf spraying of Ca and K would be better to ameliorate salinity rather than using in nutrition solution.

To study the effects of phosphorous of different sources and its solubilizing bacteria on the corn growth an experiment was conducted at Miyandoab Agricultural and Natural Resources Research Station in 2005 in Iran. The arrangement of experiment was factorial based on RCB design with three replications. Treatments consisted of four levels of phosphate solubilizing bacteria: control, thiobacillus bacteria, phosphate solubilizing bacteria and Thiobacillus bacteria and phosphate solubilizing bacteria and three levels of fertilizer: without fertilizer, rock phosphate and triple super phosphate. In this study 0.5 m2 of each plot was sampled every 15 days intervals and were studied the dry matter per unit area (TDM), leaf area index (LAI), crop growth rate (CGR) and relative growth rate (RGR) were analyzed. The results showed that the application of thiobacillus bacteria phosphate solubilizing bacteria triple super phosphate increased total dry matter (TDM) and crop growth rate (CGR), while relative growth rate (RGR), decreased. LAI increased slowly during early growing stage but increased rapidly when growth proceeded. The highest LAI (4.3), TDM (3451 gr/m2) and CGR (5.41 gr/m2) were obtained from the application of thiobacillus phosphate solubilizing bacteria triple super phosphate. Similar results were obtained by the application of thiobacillus phosphate solubilizing bacteria rock phosphate. It seems that application of thiobacillus phosphate solubilizing bacteria is useful for availability of phosphorous to plant. Also, application of rock phosphate, due to low cost, availability of phosphorous to plant and its decreased effect on environment pollution can be used instead of other sources of phosphate fertilizers such as triple super phosphate.

To investigate the effect of various levels of nitrogen fertilizer and different plant density on nitrogen use efficiency (NUE) and growth analysis of corn, a split plot experiment based on randomized complete blocks design with three replications was conducted in Ardabil Agriculture Research Station in 2005. The factors were nitrogen fertilizer at three levels in main plots (0, 75 and 150 Kg N ha-1) and plant densities in subplots (7, 9 and 11 plants m-2). The results showed that NUE was significantly affected by plant density and nitrogen levels. Maximum rate of NUE was obtained in application of 75Kg N ha-1. There was no significant difference between 75 and 150Kg N ha-1. With increasing plant density, the NUE was decreased, and maximum NUE was also obtained in density of 7 plants m-2. With increasing plant density and nitrogen levels, total dry matter, crop growth rate and grain yield were increased. Grain yield per plant decreased with increasing plant density. With increasing nitrogen levels and decreasing plant density the number of kernel per row, and number of kernel in ear were increased. Numbers of kernel in ear were only affected by nitrogen levels, and was decreased with increasing nitrogen levels. Number of ear per plant and weight of thousand grains wasn’t affected by levels of the experimental factors.

In order to compare the growth indices and phenological stages of development of two local and commercial varieties of radish in response to different levels of population, an experiment was conducted as factorial on the basis of completely randomized block design in the greenhouse in Ferdowsi University of Mashhad, Iran during 2009-2010. Treatments were included two varieties of radish as first factor and three levels of population containing 85, 120 and 170 Pl m-2 as second factor. Phenological stages and growth indices including fresh and dry weight, leaf area, relative growth rate, special leaf area, leaf area ratio, net assimilation rate, edible part yield and dry matter allocation to leaves and roots in optimal conditions since the beginning of germination until final harvest were analyzed. The results showed that there is no significant difference between two varieties in relation to the germination time and 2 and 4 leaves stages in different planting densities. But two varieties responded differently to the different planting densities since the beginning of tubering. The local variety showed higher leaf area ratio and leaf area index, and higher intercepted radiation, but the allocation of photosynthate was more to leaves than edible root. Commercial cultivar showed significantly more economic yield than local cultivar. Increasing the population to170 pl m-2 significantly increased leaf area and leaf area index, radiation use efficiency, leaf weight and biomass, but it had no significant effect on the radish root weight.

This research was carried out in the Research Field of Aboureyhan Campus, University of Tehran during 2006-07 growing season to investigate the effect of Sinapis arvensis L. interference on yield and growth indexes of different canola (Brassica napus L.) varieties. The experimental design was a complete randomized block arrangement in factorial with three replications. Eight canola varieties namely: Elite, Ebonite, Okapi, Zarfam, SLM046, Orient, Licord and Opera were planted in either pure or mixed cultivation with the weed. Trend of Dry Matter (TDM) accumulation, Leaf Area Index (LAI), Crop Growth Rate (CGR) and grain yield were investigated in the canola varieties. In general, the weed reduced growth indexes in canola varieties, but the response of canola varieties were different. Elite and Okapi were recognized as the most resistant and sensitive varieties in competition with the weed, respectively. Elite variety produced the highest grain in mix treatment while the lowest one belonged to Okapi variety, but in pure canola cultivation Ebonite and Opera yielded the maximum and minimum grain, respectively.

Weeds are problematic plants in agroecosystems as a competitor for crops. In order to evaluate effects of cotton (Gossypium hirsutum) and common lambsquarter (Chenopodium album) densities on some crop growth indices, a study was conducted during 2006 in Experimental Station of Faculty of Agriculture, The University of Birjand as factorial experiment based on complete randomized block design with four replications. Three densities of cotton (6, 9 and 12 Pl.m-2) and four weed densities (0, 6, 9 and 12 Pl.m-2) were used to provide different weed interference levels. Indeed, three plots in each replication were intended to cultivation of lambsquarter alone at 6, 9 or 12 Pl.m-2. Results showed that crop growth rate (CGR) of cotton was influenced by weed density, and its relative growth rate (RGR) and net assimilation rate (NAR) indicated a declining trend as weed density increased. Dry matter accumulation of cotton also was affected negatively by weed densities, as interference of lambsquarter at 6, 9 and 12 Pl.m-2 resulted to 35, 42 and 48 percent dry matter reduction, respectively, than weed-free treatment. Increasing of cotton density could partly compensate for negative impact of weed attendance on cotton growth. Thus, it seems higher plant densities can be used as a managing tool against weeds in cotton fields to avoid reduction of yield.

The effects of plant densities (25, 35 and 45 plants m-2 as D1, D2 and D3 respectively), and inoculation with rhizobium bacteria (without rhizobium, with rhizobium and rhizobium + microelement application), on growth and yield were studied in chickpea (Cicer arietinum L.). Experiment was carried out in 2008 at Research farm of the faculty of agriculture of University of Mohaghegh Ardabil, a factorial experiment based on randomized complete block design with four replications. Effects of plant density on seed per pod and weight of seed-100 were no significant and on yield per plant and harvest index were significant. Effects of inoculation on weight of seed-100 were no significant and were significant on seed per pod, seed per plant and harvest index. Interaction effects of plant density and rhizobium inoculation were significant on secondary branch, pod per branch, and seed per plant and grain yield (kg ha-1). Highest grain yield per plant (3.6 g) and harvest index were obtained at D1 followed by D2 and D3 with 2.6 g and 35.79 %, respectively. Highest seed per pod, seed per plant and harvest index were obtained at R3 with 1.03, 3.8 g and 43.72 % followed by R0 as 0.86, 2.5 g and 33.91%. Maximum secondary branch at D1*R1 and D1*R2, and highest pod per branch at D1, D2*R2, and highest seed per plant at D1, D2*R2 and D3*R2 were obtained. However lowest secondary branch, pod per plant and seed per plant at D3*R0 and lowest pod per branch at D2*R0 were obtained. The highest and lowest grain yield (kg ha-1) were obtained at D3*R2 and D1*R0. Study of growth index show that increasing plant density and seed rhizobium bacteria inoculation+ microelement application were increased Leaf Area Index, Total Dry Matter, Crop Growth Rate, Relative Growth Rate and Net Accumulation Rate.

To determine the threshold of photoperiodism and culmulative thermal time related to bulbing and growth analysis of Safid Behbehan, Ghermez Iranshahr and Primavera onion cultivars an experiment was conducted at Behbahan Agricultural Research Station for a year (2006-2007) based on a randomized complete block design of four replications. Seeds were sown in nursery in late October and seedlings transplanted in late January. Earliest time of bulbing was assessed using the bulbing ratio (maximum bulb diameter divided by minimum neck diameter). Bulbing occurred for Ghermez Iranshahr, Safid Behbahan and Primavera cultivars at a photoperiodism of 12 h and 7 min (19 March), 12 h and 52 min (15 April) and 12 h and 34 min (4 April) and cumulative thermal time of 1036.3, 1317.2 and 1179.8 growth degree days respectively. Bulbs were harvested when 50-80% of the foliage tops had fallen and started to collapse. The results of growth analysis indicated that the period of slow growth had been 135 days after emergence (for all the studied cultivars) and then the period of rapid growth of plants being started. Leaf area index (LAI), relative growth rate (RGR), crop growth rate (CGR) and bulb growth rate (BGR) of Safid Behbahan cultivar was higher than those in the other cultivars, so that this cultivar produced the highest yield of bulb dry weight. The yield of Bulb fresh weight in Primavera cultivar was significantly (1% level) higher than that in the other cultivars. However, due to the observation of high significant difference among bulb dry matter percentage in the studied cultivars, analysis of variance was done on yield of bulb dry weight. The obtained results indicated that the yield of bulb dry weight per hectare of Safid Behbahan cultivar was significantly (5% leval) higher than that in the other cultivars.

An experiment was conducted to study growth analysis and evaluation of change in simple non- structural carbohydrates (sucrose, glucose and fructose) during bulb formation of Ghermez Azarshahr, Zargan, Safid naishaboor and Safid Qom cultivars in randomized complete block design containing three replications. Seeds were sown in nursery in early February and seedlings were transplanted in early May. During initiation of bulbing carbohydrates accumulated in leaf bases. Before and after bulb formation (about 20 days after bulb formation) the most simple non-structural carbohydrates content was found in Safid Qom cultivar. The maximum and minimum increasing percent of simple non- structural carbohydrates components belong to glucose and sucrose respectively. The results of growth analysis indicated that the period of slow growth had been about 75 days after emergence (for all studied cultivars) and then the period of rapid growth of leaf has begun. The bulb growth rate of Zargan cultivar during the most parts of bulb development stage was higher than other culitivars, due to this reason and earliest date of bulbing, yield of mentioned cultivar was higher as compared with other cultivars. A high significant positive correlation (r = 48%) was found between relative growth rate and net assimilation rate at 1% level. Zargan cultivar produced the highest total and marketable yield, so that mentioned cultivar is recommended for Karaj region.