CROP PHYSIOLOGY
Year:2011 | Volume:3 | Issue:11|Papers Count:16

This experiment in order to evaluate the effect of weeds control and row spacing on weeds traits and agronomical characteristics of rice, Tarom Mahali cultivar, was carried out at split-plot in randomized complete block design with four replications at Sari research region in cropping year 2009. Weeds control in two levels including (non weed control and with weed control) were as main plot and spacing between row including (10, 15, 20, 25 and 30 cm) were as sub plot. Results showed the lowest and highest of weeds number, weed height and weed dry weight were obtained at spacing between row 10 cm and 30 cm, respectively. With control of weed, the plant height, panicle length, total tiller number per hill, fertile tiller number per hill, panicle number per m2, spikelet number per panicle, grain yield, biological yield and so the harvest index, increased. The most and the least panicle length, panicle number per m2, spikelet percent, grain yield, biological yield and harvest index were produced in between row spacing of 15 and 30 cm, respectively. The most of spikelet number per panicle and the harvest index were observed Therefore, weed control and row space of 15 cm due to an increased yield and yield components and growth induced decreased weeds was selected as the suitable treatment.

In order to simulate the effect of drought and nitrogen stress on grain yield, water and nitrogen use efficiency of corn CERES-Maize model was firstly calibrated and then validated. In the present research, the CERES-Maize model was calibrated using field experiments which were conducted in 1995 and 2004 cropping years in Ahvaz and Ramin, respectively, then the model was evaluated using experimented data which was conducted in 2000 cropping year in Dezful (Safiabad). Normalized RMSE and index of agreement (d) were 4.2% and 0.97% for flowering date, 8.9% and 0.96 for physiological maturity and 12.6% and 0.70 for grain yield that the results showed that the model could reasonably work in this condition. Then the simulated model with six levels of drought stress (I) including irrigation after 30%, 40%, 50%, 60%, 70% and 80% depletion of field capacity and six levels of nitrogen application (N) including 50, 100, 150, 200, 250 and 300 Kg N ha-1 were assumed using Ahvaz long lasting barometer statistic was conducted. According to the simulation results drought stress has greater negative effect in high levels of nitrogen. Water use efficiency was increased a little due to decrease in used water. Through intensive drought stress, Nitrogen use efficiency decreased. Generally where irrigation water is limited and/or there is the probability of appearing of drought stress, reduction in nitrogen application can be very important for farmers for increase economical profit. Related to obtained results of this study, in Ahvaz climat condition and soil, in corn planting, it is recommended that irrigation conducted after 40%depletion of field capacity and 200kg Nitrogen used.

Maintaining soil fertility and use of plant nutrients in sufficient and balanced amounts is one of the key components in increasing crop yields. In order to evaluation with effect of Boron foliar application on planting and morphological traits of soybean genotypes, a 4-replication in split-plot RCBD experiment was conducted under khoramabad research region of Islamic Azad University, in 2009. Foliar application in treatments in three control levels: no foliar application, foliar application two per thousand of Boron fertilizer at 50% flowering and poding, foliar application four per thousand of Boron fertilizer at 50% flowering and poding, as sub plot and soybean genotypes consisting of M9, M7 and L17 were considered as main-plots.The results showed, foliar application of Boron, increases both seed yield and biological yield, oil and protein percentage significantly Also among the under studied genotypes, M7 genotype proved higher grain yield (799/7Kg per hec), the reason for the superiority is the production of the highest biological yield and number pod per plant. About the protein trait Soybean seed exposed to foliar application of Micro nutrients Boron. Based on the obtained results of variance analysis and comparing the average data, a significant difference in 5% level was observed between 2 in 1000 and 4 in thousand Boron.M7 and M9 cultivar, in comparison to L17 cultivar had more protein.2 per thousand concentration of Bron had more share to increase Soybean seed oil in comparison with other treatments.

In order to investigate the relationship between effective traits on seed yield of two maturity groups of soybean, an experiment was conducted as randomized complete block design with three replications at Agricultural Research Farm, University of Guilan in 2009. The experimental treatment was seven soybean cultivars, namely 033, 032, Sahar (belonged to maturity group IV), L.17, Zan, Clark and Madari (belonged to maturity group III). The studied traits were included number of pods on the main stem and on branches, number of pods per plant, number of seeds per pod, 1000 seed weight, plant weight, weight of seeds per plant, number seeds per plant, oil and protein percentage, seed yield and biological yield and harvest index. Simple correlation between traits, stepwise regression and path analysis were carried out in maturity group separately. The results showed biological yield trait in maturity group IV and weight of seeds per plant, had the highest positive and meaningful correlation with seed yield. Stepwise regression analysis showed that these traits covered majority of total yield changes Then, the entered traits in. regression model were studied, and based on in it in group maturity IV, biological yield trait (r=1.04) and in group maturity III weight of seeds per plant (r=0.80) had majority of direct and positive effect on seed yield. Therefore any maintaining or planting activities in order to improve these traits, can increases Soybean yield.

One of the ways to study the inter and intra species competition is the study of under experiment treatment whole plant behavior. In order to study the effect of hybrid, plant density, and weeds competition on the experimental whole plant corn, a factorial test was performed as split-plot design in randomized complete blocks with 4 replication in Safiabad Khouzestan Agriculture research station during summer 2010. Corn hybrid was considered in two v1 and v2 levels. These hybrids are belonged to Safiabad Agriculture Research center, under study hybrids, which will introduce later. Plant density in 3 levels, 75/6 and 9 plants in m2, and weed removal 50 and 100%was done. The results showed hybrid had high significant effect on whole plant weight, ear weight per plant, grain weight per ear, grain number per plant, cab weight per plant and ratio of grain weight per ear weight. For all traits v2 hybrid was better than v1 hybrid, specially for grain weight per plant (43%).Plant density had no significant effect on traits. With increasing plant density from 6 up to 9 plant per m2, decreasing trend in whole plant traites has not been observed. Probably, the competition between corn plant (inter variety competition) for two hybrids occurs at higher densities. In another hand, optimum plant densities will occur at more than 9 plants m2 condition. Weed removal had a highly significant effect on all of traits except ratio of grain weight per ear weight. The highest values of traits obtained at level of 100% weed removal. Whole plant weight, ear weight per plant, grain weight and grain number per plant affected high significantly by interaction of plant density and weed removal. Evaluate of interaction effects indicated that probably, under Safiabad climet conditions, perhaps, increasing of plant density at weed absence, cause more shading on unit area, and because of evaporation decline and also Canopy temperature decline, improved conditions for increasing whole plant weight and grain weight per plant.

This research has been conducted to evaluate the allelepathic effect of herbal plant Hemp hydro alcoholic extract (Cannabis sativa L.) was conducted on seed germination and weeds growth of oat (Avena fatua L.), fat hen (Chenopodium album L.) and pig weed (Amaranthus retroflexus L.) in laboratory and greenhouse, using completely randomized design at three replications. The experiment treatments were extract of aerial organ of hemp in 6 concentration 0.1, 0.25, 0.5, 1, 2.5 and 5% and distilled water (control). Different concentration of Hemp extract creates meaningful decreasing in germination percentage and radical and plumule lengths of weeds seeds in laboratory. Also the results showed different concentration of extract creates meaningful decreasing significantly in fresh and dry weight and height of plant in greenhouse.5% extract concentration causes decreasing shoot dry weight of Chenopodium album, Amaranthus retroflexus and Avena fatua until 0.73, 0.11 and 0.75 gr. Generally, increasing in Hemp extract concentration, decreased generation, dry weight and plant height of weeds in this study.

Drought is one of the most important factors limiting plant growth around the world and it is the most common environmental stress. The lack of water in the pastures causes growth reduction and the establishment of varieties in this areas. Due attention to ecological importance of pastures and effects of three level of drought stress FC, FC50% on, for conserve the soil, in present research, the growth of varieties: Secale montanum, Bromus tomentellus, Agropyron desertorom from grasses and Onobrychis sativa, Medicago sativa from legoms was considered. From each species two genotypes were selected. Factorial experiment based on completely randomized design in 4 replications was conducted in greenhouse conditions. Root length, shoot length, seedling length, root to shoot ratio, root, shoot and seedling dry weight as well as dry weight to fresh ratio, the amount of chlorophyll a, b, and total were assessed. Under drought stress increased root length and the amount of chlorophyll increased and the most other traits, especially at FC 50% reduction was significant. Secale cermond ecotype seedlings had the most growth and Agropyron cristatum ecotype seedlings had the lowest growth rate and chlorophyll. In examining the interaction of drought and species the highest total chlorophyll and b chlorophyll were observed in Medicago 44 that were treated with FC 50%.From ten under studied ecotypes under drought stress, Secale cermond had the better growth.

This experiment was conducted in 2009) to obtain new and superior soybean lines in Safiabad Agricultural Research Center at north of Khuzestan in 2000. Material is containing 15 pure new lines with 2 Safiabady and 504 (control) cultivars. Experimental design is RCBD with 3 replication. Each plot regulated as 4 planting rows and longer 5 meters with row spacing 60 cm space between plants was 5 cm. Results of yield analysis showed high significant different between experimented cultivars as (Sahar*Collombus(6)), (Hamilton*T1srf) and (BP692*Safiabadi) lines with 4128, 4087 and 3993 Kg seed yield per hectare in order, were superior cultivars analyses lines (Safiabadi*Williams) and (BP692*Safiabadi) with average of 22/7% and line (dpx*For a). (No.11) with 39.8 percent were the superior lines for oil and protein percent, respectively. At the final results of this experiment and with attention to the quantitative results, these lines (Sahar*Collombus(6)), (Hamilton*T1srf) and (BP692*Safiabadi) are recommended as superior cultivars for planting in north of Khuzestan.

In order to investigate the nitrogen fertilizer and irrigation management effects on growth, yield, yield components and water use efficiency of hybrid cultivar rice (Bahar), an experiment was conducted on experimental cultivating field of Rasht rice research institute using split plot in a randomized complete block design (RCBD) with 3 replications in 2009-2010 season crops. Four irrigation management (permanent flooded, 5, 8 and 11 days interval) were chosen as the main plot and nitrogen fertilizer in 4 levels (0, 90, 120 and 150 kg N/ha) as sub plot. Results showed that irrigation management effect on yield, height, biomass, number of filled and unfilled grains per panicle, weight of 1000 grains, total tillers number, harvest index and panicle length was not significant but it had significant effect on water use efficiency based on yield and biomass. Level of irrigation increased water use efficiency based on yield and biomass in 11 days interval. Also application of nitrogen fertilizer increased all parameters except harvest index. In biomass, total tillers number, panicle length, number of unfilled grain per panicle and water use efficiency based on biomass with increasing nitrogen fertilizer levels the value of these traits increased. Thus it can be concluded that the most appropriate management of paddy for hybrid cultivar rice is 11 days interval irrigation with 90 kg N/ha.

To study the Allelopathic effects of Jhonsoiagrass, (Zea mays L.) Foxtailgrass, and Branyardgrass on seed germination and corn grass, an experiment in Complete Randomize Design with 3 replication and 13 treatments was conducted in laboratory condition in Seed Technology Lab. at Shoushtar Azad University, Agronomy group. In this experiment, the treatments were considered a combination of weeds (Jhonsoiagrass, (Zea mays L.) Foxtailgrass, and Branyardgrass) and the kind of plant organ (seed, branch, root, and a mixture if the whole organs) in the fixed 5% concentration with distilled water as control. The reaction of germination percentage and grass growth under the effect of the experimental treatments, in spite of decreasing to control treatment, showed different behavior in response to the water extract of the variety and plant organ. As, among the weeds, Foxtailgrass had the most and Branyardgrass the least inhibition effect. and among the plant organs; the branch, seed, root and the whole plant extract, respectively, caused the highest limitions. Results showed the necessity for controlling weeds befor, during and after corn grass growth.

Environmental heat increase, and effective raining cut off, are special characteristics at the end of autumn crops season growth in south warm region. So, wide compatible varieties introduction are essential parameters for seed yield stability production in this regions. In this experiment 12 superior canola genotyps were compared in randomized complete block design, with three replication, in Ahwaz, Behbahan, Hajeabad and Iranshar agricultural research station in different environmental condition, and normal planting date, as control treatment, normal planting date and late irrigation cut off for using drought stress treatment and late planting date for heat treatment were compared for two agronomy years 2003-2004, 2004 and 2005. Compound variance analysis and seed yield ranking results showed that Hyola401 with 3554.9, 3126.1 and 2419.0 Kilogram per hectares seed yield production in normal, drought and heat condition, respectively, had less rank and standard division, and so among the superior, compatible and recommended hybrids in south warm region and option500 variety in case the least seed yield and incompatibility is not suggested for planting in this region.

This research was carried out to investigating the effect of winter and summer planting dates on morphological characteristics, yield and yield components of rice cultivars in Khuzestan condition for one year. The experiment was performed as split-plot design in randomized complete blacks with 3 replications in shavoor Agricaltural Research station. The main plots were planting date in 3 levels (15 March, 14 April, 26 May) and the subplots were including cultivars name Dollar, N22, Gerde zanjan; 3local cultivars of Hoviezeh, Gerde Ramhormoz and Hamar (resistant to heat), two foreign cultivars (CR547-1-2-3 and IR1567-228-3-3) and 2 lines of 7 and 13. The results showed that the highest yield, number of full seeds and fertility percentage were related to Hoveizeh and Hamar cultivars in third planting date; with average 4898.1, 4804.4 kg/ha, numbers of full seeds with average 116 and 181 panicle and the highest fertility with average, 88/42, 95.86 percentaye repectively. The highest, dry matter obtained in Hamar. The line 7 had the highest of 1000-grain weight. In characteristics of plant number in m2, plant height, the highest amount was related to 3rd planting date. But panicle length had the highest amount in 2nd planting date; while width and height of flag leaf had highest amount in first planting date. Finally, in according to results foreign cultvar of IR1567-228-3-3 is recommended for winter culture (had the highest index in 3 planting dates) and Hoviezeh and Hamar are recommended for summer culture.