CROP PHYSIOLOGY
Year:2012 | Volume:4 | Issue:15|Papers Count:10

In order to investigate the effects of intra row space on yield and yield components of soybean cultivars in summer cultivation in Khormabad, an experiment was conducted in Jahad agricultural research region of Khormabad in summer of 2008. The experiment was conducted as factorial in randomized complete block design with 4 replications including 4 intra row space (3, 6, 9 and 12 cm) and 4 cultivars (Zan, Hack, Steel and Harcoor). Results showed that intra row space had significant effect on traits of pod number in plant, grain yield, biological yield and harvest index. Effect of cultivar was significant in all of measured traits except harvest index and interaction of these two factors was un significant on non of these traits. Means comparison showed that by increasing in intra row space, grain yield decreased, so that intra row space of 3 cm and 12 cm produced maximum (3009.5 kg/ha) and minimum (1683.6 kg/ha) grain yield, respectively. Also between cultivars, Zan and Steel cultivars had highest (2557.0 kg/ha) and lowest (1834.2 kg/ha) of grain yield, respectively. Generally and by attention to the obtained resultes, maximum grain yield obtained in intra row space of 3 cm and Zan cultivar.

In order to study the effect of drought tension on some qualitative and quantitative characteristics of rapeseed cultivars and to assess tolerance of these cultivars to drought, an experiment was conducted in 2007 in a farm located at 5 kilometers from west of Shirvan city, as factorial in the basis of randomized complete block design with three replications. The experiment treatments consisted of three levels of drought tension S1=without irrigation cut off, S2=irrigation cut off in vegetative growth stage (stem developing) and S3=irrigation cut off in generation stage (flowering), and three different cultivars of rapeseed were C1=Zarfam, C2=Ornit and C3=likord. The under studied characters in this research consisted of biological yield, grain yield, 1000-seeds weight, rapeseed oil density and seed protein.Results showed that tension had negative significant effect on all of the measured characters. So that the highest biological yield, grain yield, 1000-seeds weight and oil density and protein content in seed obtained from full irrigation treatment. Among the cultivars, the highest amount of all characters except seed and oil protein density achieved from Zarfam cultivar. On the basis of resistance indicators of MP, GMP and STI Zarfam cultivar was in the highest level and was recognized as a resistant cultivar.

This research has been conducted in order to investigate the effect of hydroalcoholic extract of root and rhizom of Golden Wings herbal plant on germination and growth of four weeds varietiesAvena fatua L., Chenopodium album L., Setaria viridis L. and Amaranthus retroflexus L. as laboratory and greenhouse using completely randomized design at three replication. The experiment treatments including six densities of Golden Wings exteract 0.1, 0.25, 0.5, 1, 2.5 and 5% and distilled water (control). Results showed different densities extract of Golden Wings plant significantly decreased germination persentage and radical and plumule lenght of weed seeds in laboratory. Also, different densities of Golden Wings plant extract created significant effect on germination seeds percentage, hight and fresh and dry weight of weeds shoots in greenhouse. Results showed at 1% concentration of Golden Wings extract in laboratory reduced the germination percentage of Amaranthus retroflexus, Chenopodium album, Setaria viridis and Avena fatuaseeds 74, 30, 57 and 68 percent respectively in comparison with control.1% concentration of Golden Wings extract in greenhouse reduced the germination percentage of Amaranthus retroflexus, Chenopodium album, Setaria viridis and Avena fatua seeds 78, 82, 52 and 70 percent respectively in comparison with control. Results showed that the extract of Golden Wings plant has powerful allelopathically effects and inhibits germination and weeds growth, so it might be used in producing natural source herbicides.

In order to investigate the effect of nitrogen fertilizer and seed density on the agronomy characters and yield of rapeseed this research was conducted in a split plots design as randomized complete block design in 2009 cropping year. Net nitrogen treatment including application of measures 0, 100, 200 and 300 kg.ha-1 and different amounts of seed including 6, 8 and 10 kg.ha-1 were used in main supplots, respectively. The obtained results showed that the amount nitrogen fertilizer consumption had significant effect on plant height, number of branch, silique per plant, 1000-seed weight, grain yield, oil percentage and oil yield. The results of comparing the average of oil and seed yield showed that using 200 and 300 kg/ha net nitrogen was higher than other levels with 1353 and 48.6 kg/ha. Seed rate had significant effect on branch number, siliqe number per plant, oil and seed yield. Comparison of means showed that the effect of seed rate on seed and oil yield by using 6kg seed with the averages of 1164 and 4100 kg/ha, respectively was higher than other amounts. In comparison nitrogen and seed ratses interactions, the highest seed and oil yield was obtained as the average of 4887 and 1236 kg/ha, respectively when it was used 300 kg/ha net nitrogen and 6 kg/ha seed.

In order to identify the relationship between grain yield and its componants, correlations analysis and find out direct and un direct effects of different traits on soybean seed yield, 16 new lines of soybean with a control cultivar 504, as a randomized compelet block design with 3 replications was investigated and compared in Safiabad Agriculture Research Center in 1388. Each plot was 4 rows along 5 m and row spacing 60 cm and space between plants was adjusted 5 cm. Results showed that the biological yield and harvest index had the highest positive correlation coefficient r=0.64 and r=0.53 respectfuly with seed yield. The results of multi parameters regression as Backward method showed the characters protein percent, biological yield, seed per plant, harvest index, 100-seed weight and seed yield per plant with r2=0.83 are effective characters on seed yield. The results of path analysis showed seed yield per plant, harvest index and biological yield had highest positive direct effects, and characters seed summer per plant and 100-seed weight were highest positive indirect effects on soybean yield. So, the characters seed yield per plant, harvest index, biological yield, seed number per plant and 100-seed weight respectfuly should be considered in soybean improvement programs.

In order to investigate the effect of nitrogen on yield components, grain yield and nitrogen use efficiency of Sunflower cultivars (Heliantus annus L.), an experiment was conducted in 2009-2010 cropping year in the field of education- research of College of Agriculture of Islamic Azad University of shoshtar. The research was a split plot design in a completely randomized block bases with 3 replications.The main treatments were three levels of nitrogen Fertilizer (0, 75 and100 Kg/ha net nitrogen) and sub treatment contained of three cultivars (Master, Lakomka and Allestar). The results of this investigation showed that the effect of increasing nitrogen on grain yield, 100-seeds grain weight, number grain per head and oil yield were significant, however, decreased grain oil percent.Difference between cultivars were in terms of grian yield, so that the highest greain yield (2695.3 kg/ha) was obtained from Allstar and the lowest grain yeild (1959 kg/ha) from Lakumka cultivar. Interaction of nitrogen and cultivar on grain yield, number of seed per head and 1000-seeds weight was significant but not significant on head diameter. Nitrogen use efficiency was significantly affected by cultivar and nitrogen levels. The comarison of means showed that by increasing nitrogen, fertilizer efficiency use, decreased and there was significant difference among the cultivars.

This experiment was conducted in the silty clay loam soil feilds of Safiabad Agricultural Research Center (the semiarid region of north of Khouzestan) in order to investigate the effect of surface and gun sprinkle irrigation on yield and water use efficiency of alfalfa. Therefore, gun sprinkle irrigation with two kinds of nozzle (with 22 and 24mm diamerers) one for every harrest and furrow irrigation system (with 150 m long furrows and 60cm distance and 0.002 slop ground). Statistical analysis showed that using heavy, infrequent irrigation (surface irrigation) reduced total dry matter yeild and water use efficiency. So that maximum and minimum yield and WUE for two harvests were 16.27 and 11.5 ton/ha and 2.11 and 0.49 kg/ha Perm-3 dry forage instead of each m3ph water for the frequent (Gun sprinkle irrigation), and infrequent (surface irrigation) irrigation regimes, respectively. It can be concluded to obtain high forage yeild and increase water use efficiency of alfa alfa in semiarid conditions, irrigations should be light and freqently by using sprinkle irrigation system.

In order to investigate the effect of weeding time on the species composition, density, dry weight and physiological characteristics of weeds in sweet corn (sc 403) an experiment was conducted in a randomized complete block design with four replications in the farm of Shahid Salemi located in the notheren of Ahvaz, during 2010. Treatments included weeding different phonological periods of corn growth including4 th leaf (V4, 6 th leaf (V6), 8 th leaf (V8), 10 th leaf (V10), 14 th leaf (V14), tasseling with weed infestation treatments till the mentioned stages and two weeding treatments and weed infestation to the end of growth season as control. Data of this experiment was obtained by measuring weeds characters of control treatments in the end of season and infestation treatments in the end of above stages. Results showed that weeds density at infestation treatments increased to corn8 th leaf stages and after it, decreased but the weeds delivered their copmetitve pressure in to the plant community. Also, weeds dry weight and density in the end of season during the control stages had an decreasing trend and Pig weed has recognized as the dominant weed and the highest leaf area indexand weed speed rate durind infestation stage was related to this weed. In this experiment, weeds control after10 th leaf and before4 th leaf corn stage, had not significant effect on increasing yeild.