JOURNAL OF CROP ECOPHYSIOLOGY
Year:2012 | Volume:3 | Issue:4|Papers Count:9

In order to evaluate removing leaf and seed stress in different plant densities on growth stages and its relation to yield of sunflower hybrids, an experiment was conducted in factorial split plot based on RCBD with three replications in 2009 at Aboureihan research farm of university of Tehran. Azargol and new Iranian hybrid SHF 81-90 and three plant densities 60000 80000 and 100000 plants/ha as main plots and five level of removing leaf and seed (removed 50% lower leaves, removed 50% upper leaves, removed 50% seeds, removed 25% seeds and control treatments were sub plots. The results indicated that effect of removing leaf and seed treatments was significant on reproductive period, seed filling period, growth period, seed yield in head, dry weight of plant, dry weight of head with seeds, productivity effort, oil percent and 1000 seed weight at 1% probability level. Interactions between treatments on yield dependant characteristics were significant at 1% probability level. Also correlation between seed filling period with dry weight of head with seeds (r=+0.636), productivity effort (r=+0.714) and 1000 seed weight (r=+0.799) was positive and significant. The highest positive and significant correlation was observed between dry weight of head with seeds and dry weight of plant (r=+0.965). By removing leaf in different plant densities, because of reduction in produce photosynthetic materials, period of phenological stages decreased and yield reduced severely.

In order to investigate rapeseed reaction to the nitrogen amounts and irrigation regimes under application/ no application of zeolite (kind of natural superabsorbent), a field experiment was conducted in a randomized complete block design at a factorial layout with three replications at the Research Station of Islamic Azad University-Takestan Branch, Iran in 2009-2010 cropping season. Irrigation factor consisted of normal irrigation (control) and halt in irrigation started from flowering stage. In addition, three levels of zeolite (0.5 and 10 t ha-1) along with nitrogen rate of 0.75 and 150 kg ha-1 were studied. Improved cultivar of "Okapi" was applied for sowing. Results indicated that the individual effects (irrigation, nitrogen and zeolite) and interaction of irrigation × nitrogen, irrigation × zeolite, nitrogen × zeolite, were highly significant on the Grain yield (p<0.01). Normal irrigation by consumption of 150 kg N ha-1and 10 t zeolite ha-1(with the means of 5278 kg ha-1) had the highest Grain yield. Water deficit stress as ceased irrigation from the flowering stage together with not applying nitrogen and zeolite (with the means of 599 kg ha-1) resulted in the lowest Grain yield. Totally, consumption of 150 kg N ha-1 together with applying 10 t zeolite ha-1 (Under normal irrigation) and consumption of 75 kg N ha-1 with applying 10 t zeolite ha-1 (Under stopping irrigation from the flowering stage) produced the highest Grain yield.

An experiment was conducted at the agricultural research farm, collage of agriculture, Isfahan University of Technology to evaluate the effects of row spacing and plant density on grain yield and growth parameters of safflower, a local variety of Isfahan, "Koseh" in summer planting. The experimental design was a randomized complete block with a split-plot layout and four replications. The main plots were row widths (20 and 30 and 45 cm) and the sub-plots were plant densities (40 and 50 plants m-2). The number of days from planting to different growth stages and the amount of LWRmax were decreased while the amounts of LWRmax, SLAmax, SLWmax was increased as row spacing was increased. There were about 27.3 and 37.5 percent decrease in the rate of remobilization of photosynthesis and grain yield respectively and also about 14.5 and 13.4 percent increase in the efficiency and contribution of remobilized photosynthesis from vegetative parts to the grains when row width changed from 20 to 45 cm. Increasing plant density significantly reduced the number of days from planting to initiation of flowering, 50% flowering and physiological maturity. There were also about 24.5, 23.2 and 18.8 percent increases in the rate, efficiency and relative contribution of remobilized photosynthesis at higher plant density treatment. A change in plant density from 40 to 50 plants m-2 significant decreased the values of LARmax and SLWmax but there were no significant effects of plant density on the values of LWRmax, SLAmax and safflower grain yield. It can be concluded that under condition of this experiment. The results from this experiment show that to obtain the optimum yield from summer planting of safflower, under conditions similar to this study, a planting pattern combination of 20 cm row spacing and 50 plants m-2 plant appears to be suitable.

This experiment was carried out using by a randomized complete blocks design with four replications to determination of the effect of different irrigation times on seed yield and its components of Descurainia sophia under semi-arid conditions at Shahr-e-Qods zone in Iran during 2011. The factor was including irrigation times (irrigation after 10 days, irrigation after 15 days and irrigation after 20 days). The results showed that irrigation times significantly affected seed yield, thousand seed weight, silique number per plant and seed number per silique. The highest seed yield, thousand seed weight, silique number per plant and seed number per silique were achieved irrigation after 10 days. The findings showed that the time of irrigation is very important because variation in irrigation period can be stress during plant growth and it can decrease the quantity and quality characteristics in plant.

In order to investigate of fifteen wheat genotypes with winter, spring and facultative growth types to cold stress, two field and laboratory experiments were organized in Agricultural Research Center of West Azerbaijan Province in 2007-8. Arranging of laboratory and field experiments were Completely Randomized Design with five replications and Randomized Complete Blocks Design with three replications at three different planting dates, respectively. Results of laboratory analysis showed that differences between genotypes on ion leakage, potassium accumulation and total dry matter were significant. The most and less potassium accumulations were allocated for C-81-14 and Sayson genotypes, respectively. M-81-13 and Zarrin genotypes had the highest and lowest levels of ion leakage. Within cultivars Gaskojen had more total dry matter and Zarrin, Kavir, M-81-13 had the low values. At six leaves step, spike was observed for spring types, but at winter and facultative types there was no apex. Combined analysis of variance for field experiment demonstrated that between three sowing dates, cultivars and interactions of c×d for traits of plant height, spike per square meter, 1000-kernel weight, and grain yield, total dry matter was significant. Having negative correlation of ion leakage with total dry matter and grain yield could be used an indirect criterion for screening of tolerant genotypes. Resistant genotypes to cold stress became Alvand, Tus, C-82-12, M-79-7, Zarrin, Kavir, Mahdavi, and Gaskojen.

Wheat crop, considering its high planting area and consumption at national scale, demand a regular yield increase. Humic acid, as an organic acid obtained from humus and organic sources without any environmental destructive effects and Plant growth promoting bacteria through the effects of hormonal and nutrient improve uptake to raise grain yield in wheat, especially in terms of salinity can be effective. The effects of salinity on growth and changes phytohormone in wheat inoculated with Plant growth promoting bacteria and Humic acid, an experiment was conducted in 2010 at research greenhouse, Faculty of Agriculture and plant breeding, Islamic Azad University of Karaj Branch. A completely randomized block design with three replications was using analysis of factorial. experimental treatments included two levels of Humic acid {(A0): Control, (A1): Humic acid consumption}, and salinity levels in the three levels of {(B0): Control, (B1): Low salinity of 75 mM, (B2): High salinity of 150 mM}, the use of microorganisms in the five levels of {(C0): Control, (C1): Grain inoculation with Azospirillum lipoferum , (C2): Grain inoculation with Azotobacter chroocccum, (C3): Grain inoculation with Pseudomonase putida, (C4): The mix grain inoculation with (Azotobacter chroocccum, Azospirillum lipoferum, Pseudomonase putida)}.The results showed the effect of grain inoculation with plant growth promoting bacteria and Humic acid consumption during exercise salinity on Grain yield, Gibberellins, Auxins and Cytokinin was significant. The highest grain yield of treatments inoculated with Azetobacter chroocccum bacteria and humic acid no consumption and the salinity was 75 mM, and Most of Cytokinin and Gibberellins hormone with the treatment grain inoculation with Azospirillum lipoferum and Humic acid no consumption and salt stress of 150 mM was while the highest Auxin hormone with the mix treatment inoculation with plant growth promoting bacteria and Humic acid consumption and no salinity stress (control).

In order to study Effect of planting date on seed yield and yield components of different corn hybrids, a field experiment was conducted in a split- plot arrangement using randomized complete block design with four replications in Miyandoab Agricultural Research Station in 2005-2006. The planting date (main factor) consisted of levels (15 and 3o May and 14 June) and the sub- factor consisted of 15 corn hybrids (KSC704, KSC700-late maturing, KSC647, KSC604, KSC500- mid maturing, KSC400, OSSK444, BC404, KSC302, KSC340, OSSK373, BC354- midearly maturing, BC282, KSC260, BC250- early maturing). The results showed that the effect of planting date on ear length, seed number per row, seed depth in ear and seed yield were significant. The highest seed yield (11.54 ton/ha) belonged to second planting date (30 May) and the least (7.8 ton/ha) was obtained from the third planting date (15 June). The results also showed that the effect of corn hybrids was significant on all traits. The highest seed yield (12.05 and 11.6 ton/ha) belonged to KSC604 (mid maturing) and KSC704 hybrid (late maturing), respectively. Interaction between varieties planting date was significant on the number of seed Rows per Ear (p<0.05) and on seed deep in ear and seed yield (p<0.01). The highest seed yield (15.12 ton/ha) and was obtained from the third planting date (15 June) KSC704 hybrid (late maturing). According to this study the planting dates of 15 and 30 ordibehesht for the late and mid maturing cultivars are recommended for the experiment region and other similar regions.

Reduction of environmental pollution caused by fertilizers, especially urea consumption practice in Gilan province has caused many problems respectively. In this experiment, three irrigation management (I1=control with 100% and I2, I3, respectively, with 80% water, 60% evaporation from the water evaporation pan) as the main agent and different amounts of azolla compost at 4 levels (C1, C2, C3 and C4, respectively 0, 4, 8 and 12 ton/ha) was considered as a secondary factor. Potassium in the grain was significant and the interaction of nitrogen and phosphorus in irrigation and composting plant was significant and the highest grain yield of rice treated with 60% evaporation and using azolla compost was 8 ton/ha. Generally conclude that application of compost increased the yield and also reduces the use of fertilizers.