JOURNAL OF RESEARCH IN CROP SCIENCES
Year:2012 | Volume:4 | Issue:15|Papers Count:13

To understand the responses of antioxidant system of alfalfa (Medicago sativa L.) to drought stress, a completely randomized design was carried out. Based on soil water content, drought stress levels of 100, 75, 50 and 25% of field capacity (FC) were prepared. The effects of these levels of drought stress on anthocyanine, b-carotene, lycopene and synapoyl derivates were investigated. The analysis variance of results showed that drought stress caused the increases in anthocyanine, synapoyl derivates, b -carotene and lycopene contents of alfalfa in comparison with control (p<0.01). In drought levels of 50 and 25%FC, the contents of anthocyanine and synapoyl derivates increased significantly as compared with control (increased by 5.72 and 14.02 folds for anthocyanine whereas by 1.69 and 1.83 folds for synapoyl derivates respectively). Similarly, the contents of b -carotene increased significantly in 75, 50 and 25%FC in comparison with control, although there were no significant differences in b-carotene contents between drought levels of 75, 50 and 25%FC. In the case of lycopene, all other levels of drought except 25%FC had no significant differences in comparison with control. Drought stress caused oxidative damages which trigger cell membranes; therefore, antioxidant compounds such as anthocyanine, synapoyl derivates, lycopene and b -carotene are useful for plant survival in drought stress conditions.

In order to evaluation drought stress tolerance and sensitivity indices and their relation with grain yield on advanced wheat genotypes under normal and water stress after anthesis, this experimental carried out at agronomy and natural research station of Ardabil in 2008-2009. Ten advanced winter and intermediate wheat genotypes obtained from agronomy and natural research center Ardabil were evaluating in two separated experiment under normal irrigation and after anthesis drought stress condition in a randomized complete block design experiment with three replications. The highest and lowest grain yields (6093.3 and 4819.4 Kg per hectare) were obtained by normal and water stress conditions, respectively. The lowest value of stress sensitivity index was belonged to 7 No genotype and follow that were 6 and No genotypes. There has negative and significant correlation between SSI with yield potential stress (Ys) and negative relation with yield potential normal (Yp). Genotypes with 6 number with 10 No genotypes have the highest value of Stress tolerance index. Between this index with Yp and Ys were positive and significant correlations. Also relative between SSI and STI was negative. In based of result obtain, STI, MP and GMP were sufficient indices for selection drought stress tolerant wheat genotypes.

In order to study of planting date and cultivars effects on quantitative traits of sunflower in second planting, a split plot experiment on randomized complete block design with four replications was carried out in Islam Abad Agricultural Research Station. Sowing dates with 4 levels including June 22 to July 22 with 10 days interval as main plots and cultivars including Azargol, Allstar, Shafagh and CMS26*R103 as sub plots was evaluated. Variance analysis showed that sowing date and cultivar had statistically significant effects on seed yield, 1000 seed weight, head diameter, harvest index, oil and protein content percent. The results showed that the first and the latest sowing date had the highest seed yield with 3849 and 3391 kg/ha, respectively. Mean comparisons analysis using Duncan's multiple range test showed that Azargol with 4152 kg/ha had the highest seed yield. Difference among cultivars was due to dereference in days to emergence and days to flowering. Shorting this period caused a reduction in dry matter, seed yield, head diameter, 1000 seed weight and harvest index in different planting dates. Planting date effects on seed yield acted via changing traits such as harvest index and leaf area index, mainly.

In order to evaluate the effect of barvar-2 phosphate biofertilizer and foliar application of micro nutrient on the yield and the yield components of grain corn (Var. single cross 704), this experiment was carried out using factorial experiment design with two factors in effect based on randomized complete block design at three replications in Gharakandi village of chaipareh in 2010. In this experiment, the first factor (A) was in 3 levels: a1= barvar-2 phosphate + triple superphosphate, a2 = barvar-2 phosphate (inoculation of seed), and a3= triple superphosphate (soil application). The second factor (B) was in 5 levels: b1= B, b2= Zn, b3= Cu, and b4= Mn with foliar application of micronutrients, and b5= non foliar application of micronutrients. The results showed that plant height and number of grain row were affected by both of the factors. The effect of factor B especially Zn was significant on number of leaves, the number of grain in ears, ear diameter, straw yield, and biological yield, But the effect of factor A was not significant for this characters. The effect of barvar-2 phosphate was significant on grain depth in ear. The interaction of both the factors and the foliar application of micro nutrients had significant effect on grain yield and cob diameter. Totally the results showed that when the phosphates in the soil are in the average limit, this can increase the growth index and crop yield by dissolving a solution phosphates resources. The results of comparison showed that the barvar-2 phosphate biofertilizer was cost savings and reduced consumption phosphate fertilizer and the foliar application of micro nutrients because of Removing shortage their nutrition effect, increase the growth and adjusts development and finally improve yield and yield components. Highest grain yield was 15.89 t/ha in b2 treatment, and the lowest one was 12.7 t/ha in control treatment.

To evaluate foliar spraying of Homeopathic and plant growth inducers on grain yield and its components of corn varieties, a factorial experiment with randomized complete blocks design at four replications was conducted in Saatlo agricultural research station at field conditions in 2010. Plant growth inducers (Homeopathic (C30), Mar marine, Stimurel, Hyper-tonic and control) and two corn cultivars (SC504 and SC704) arranged at two factors. Foliar spraying of plant growth inducers was done at two knee-shape and tassel emergence stages. Results of analysis of variance showed that traits of plant height, ear distance from ground, ear length, grain per row, ear wood diameter, grain yield, grain per ear and row per ear for one of factors and interaction between them were significant differences at least 0.05 probability. Mar marine and Homeopathic growth inducers increased grain yield with increasing grain per row, row per ear and grain per ear. Within combination treatments, Mar marine and Stimurel growth inducers had the most grain yield at 504 and 704, respectively. In contrast, Stimurel and hyper-tonic produced lower grain yield at 504 and 704, than control, respectively.

In order to evaluated the effect of plant density and planting rate of corn and cowpea in intercropping system an experiment in split plots design with RCBD in three replications in 2010 year in Khoy. Plant densities were 55000,70000 and 85000 plant per hectare for 704 silage corn, and 300000, 400000 and 500000  plant per  hectare for cowpea as main plots, and  planting rate of  plants  included: R1: 100% corn, R2: 75 % corn + 25% cowpea, R3: 50% corn + 50% cowpea, R4: 25% corn + 75% cowpea and R5: 100% cowpea as sub plots. The results showed that highest density in corn the highest fresh forage yield (65570 kg in he) and the corn dry matter yield (1739 kg was the best density in this experiment. Also the 50: 50 planting rate (silage corn – cowpea) for the had to most production of the fresh forage yield (63957/11 kg in he) and the dry matter (11699 kg in he) as a beast treatment selected. The evaluation of the assessment indexes in the intercropping also showed that the this planting rate in high density (D3R3) and equivalent ratio with 2.01 was higher than sole cropping and were better than other levels of planting rates that shower the efficiency of intercropping. Also, the highest relative value total was relevant to (D2R3) treatment. In comprise of competition indexes the highest dominancy in all treatments were relevant to corn.

To study the effect of drought stress at different phonological stages on yield and yield components of soybean cultivars, an experiment was conducted at the experimental farm of Darrehshahr Agricultural Station, Ilam Province (2009). The experiment was arranged as split plots based on Randomized Complete Block Design with three replications. The treatments that were drought stresses during the 4 leaves stage, flowering stage, podding stage and seed filling stage were located in the main plot and three cultivars (including M7, M9 and Hobit) were located in the sub plot. The results showed that in the %1 statistical probability level, the effect of drought stress and variety on plant height, fertile pod per plant, seeds per plant, seed yield, biological yield, hundred kernel weight, seeds per pod, harvest index and oil percentage were significant. Among soybean cultivars, M9 had the best performance regarding the seeds per pod, hundred kernel weight, seed yield and biological yield. The lowest seed yields were observed in the drought stress during the seed filling stage (2682 kg/ha) and flowering stage (2918 kg/ha), respectively. Both in stress and non stress conditions, the Hobit cultivar produced higher oil percentage than others. Finally, according to the results, M9 is recommended in Darrehshahr region and among all phonological stages, seed filling stage was more sensitive to drought stress occurrence.

To evaluate and study the response of different chickpea genotypes to drought stress and determinate of drought tolerance and high grain yield genotypes, this experiment was conducted with 41 Kabouli type chickpea genotypes including of susceptible check (ILC 3279). The experiment was performed in a RCB design with two replications under stress (rainfed) and non-stress (irrigated) conditions during 2006-07 and 2008-09 cropping seasons at Maragheh agricultural research station. In this regard, stress susceptibility index (SSI), stress tolerance index (STI), geometric mean productivity (GMP), tolerance index (TOL), mean productivity (MP) and harmonic mean (HM) were calculated. The results showed that in rainfed and irrigated conditions the highest grain yields produced by FLIP 02-70C (with 1268 Kg/ha) and FLIP 87-59C (with 2112 Kg/ha) genotypes, respectively. Ranking of genotypes based on grain yield in both stress and non-stress conditions showed that genotypes No. 1 and 15 had high grain yields and stability among the tested genotypes. Evaluation of genotypes with stress tolerance indices showed that FLIP 87-59C, FLIP 02-69C, FLIP 02-70C and  FLIP 02-48C had high GMP, STI, MP and HM indices and were identified as drought resistant genotypes. The coefficient correlation of MP, GMP, STI and HM with grain yield in both stress and non-stress conditions were positively significant. These criteria were recommended as desirable indices for determination of resistant chickpea genotypes.

To study the effects of different sowing date by companion plants on some of agronomic traits of corn Sc 504, an experiment was carried out in 2010-2011 in research farm of the agriculture faculty of university of Tabriz. The experiment was carried out in a factorial arrangement with the base of randomized complete block design in three repetitions. The treatments of this experiment included type of medical and cover plant in 4 levels (Clover, hairy vetch, basil and dill) as first factorial and time of cultivating forage and medical plant in two levels (synchronic cultivation with corn and cultivation 15 days after corn cultivation) as second factorial. The results showed that the companion plants height, companion plants biomass, dry ear weight, grain yield and harvest index under effect of the time of cultivation and the type of companion plants as the highest amount of these traits were seen in treatment of the corn with clover and the lowest amount were seen in the treatment of the corn with dill. Treatment composition of companion plant × the time of cultivation on number of grain per ear was significant, and the treatment of synchronic cultivation of corn with clover and the treatment of dill with 15 days delay in comparison with the cultivation of corn had the highest average of 274.59 and lowest average of 144.85 amounts, respectively. This is due to the rapid growth, competitive ability and better weeds control and reduction inter specific competition species by the clover.

This study was carried out at the research farm of Agriculture faculty, Bu- Ali Sina University, in 2008- 2009, to evaluate the effects of winter cereals green manure for tuber growth rate, emergence speed of potato, soil temperature and potato yield. The experiment was a randomized complete block design with three replications. The trial included of green manure of barley, triticale and rye each one with common plant density and triples plant and control (Weeds residue). The results showed that rye and barley with triple plant density produced 1503.5 and 1392.2 g/m2, respectively and was prior to the other treatments. Rye and barley with triple plant density and rye with common plant density increased 12, 11 and 7 percent average soil temperature to the control treatment, respectively. These treatments increased 20, 12 and 11 percent emergence speed of potato compared with control treatment, respectively. Rye and barley with triple plant density and rye with common plant density in 60 day after emergence had maximum tuber growth rate. Other treatments in 75 days after emergence had maximum tuber growth rate. The treatments, Rye and barley with triple plant density and rye with common plant density with produced 58.21, 58.88 and 65.37 ton.ha-1, respectively and were prior to the other treatments. These treatments increased tuber yield of potato 33, 35 and 50 percent in comparison to control treatment, respectively.