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The present study was conducted to investigate the effect of different levels of irrigation and withholding irrigation on yield and yield components of cornhybrid S.C.704 in 2009 in Ahvaz Shahid Salemi Experimental Field.The experiment was set up as a factorial in a randomized complete block design with three replications. Treatments were arranged with three irrigation levels:I1,I2 and I3 in which each was irrigated equivalent to 100%(control),80% and 60% available water into targeted soil respectively .Using pan evaporation of class A to calculate the quantity of water in regard to evaporation for each treated plot,and three levels of withholding water:S1,S2 and S3 which following with no implement of water stress (control), withholding water at the stage of 8th leaf growth and withholding water at the silk stage, respectively. The results of data analysis indicated that there was significant effect on kernel and dry matter yield due to irrigation and non-irrigation treatments. As drought stress severity was promoted kernel, dry matter yield, harvest index and biological yield were significantly decreased. Severe drought stress (I3) caused reducing the kernel yield by 59% when compared to plants grown under control (I1) condition. Withholding water during silk stage drastically reduced corn yield in comparison with withholding water at the stage of 8th leaf growth and control treatments.Reduction in number of seed row in cob, number of seeds per row and 1000–grain weight were primary factors for corn yield and yield declining.

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In order to evaluate the best sowing date and its effect on yield and yield components of sunflower cultivars, a field experiment was done as split block design in a randomized pattern of complete block design with three replications in 2009 in Shahinshahr , Isfahan. The sowing date was studied in four intervals : 22 June,2009, 1 Jul,2009,11 Jul,2009, and 21 Jul 2009. The four factors used were, Alestar, Azargol, Master and Zaria. The results showed that sowing date had a significant effect on the number of seed, weight of thousand seeds, seed yield, LAI, Cap diameter and oil percentage. The higher seed yield (4170 kg/ha) was obtained from the first sowing date (22 June.2009), and the lowest seed yield (2230 kg/ha) was obtained from the last sowing date (21 Jul.2009). The average of seed yield in 1 Jul.2009 and 11 Jul.2009 was 3980 and 2760 kg/ha. The highest number of seed (759.5) and weight of thousand seeds (55 gr) was obtained from 22.June.2009 and the lowest number of seed (619.3) and weight of thousand seeds (36 gr) was obtained from 21.Jul.2009. The cultiver had a significant effect on all studied traits except the number of seeds. The highest and lowest seed yield were related to Azargol (4090 kg/ha) and Alestar (2450 kg/ha). The seed yield of Zaria and Master were 3500 and 2910 kg/ha. The highest and lowest weight of thousand seeds was obtained from Azargol (57 gr) and Alestar (38 gr).

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In order to study the effect of drought tension effect at the end of season on grain yield and the assessment of lines tolerance to tension, this experiment was conducted in a randomized complete blocks design in the Agricultural Research station of Kheirabad Zanjan. In this experiment 14 genotypes of bread wheat selected from the breeding experiments of cereals sector of Zanjan Agricultural Research center were under irrigated and end seasonal drought tension in two separate experiments. Results of variance analysis showed that in the absence of tension conditions between genotypes for all traits of genotypes except biological yield there was significant difference at the probable level of one percent and biological yield at the probable level of five percent. Results of variance analysis in drought conditions showed that between all genotypes traits except grain yield at the probable level of one percent and regarding to grain yield trait at the probable level of five percent there was significant difference. Based on tolerance indices (STI, MP and GMP) genotypes 11, 6, 9 and 4 were more tolerant genotypes. Among the mentioned genotypes, genotype 11 which had the highest indices amount of STI=0/98, MP=4765/05 and GMP=4723/11 and has had the highest yield under drought tension conditions (Ys) (4134/26 kilogram per hectare), was selected as a high-yielding and tolerant genotype.

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In order to evaluate the effect of water stress on sunflower cultivars of Iroflor in different stages of growth and methods of biophosphate consumption, a factorial experiment was conducted in a randomized complete block design with four replications. Water deficit stress in four levels including control (non-stress), stress in vegetative stage, stress in reproduction stage and stress in both vegetative and reproductive stages and application of biofertilizer (Phosphate Fertile 2) in four levels including non use of biofertilizer, seed coated, topdress and and combined application seed coated and topdress. The results showed that water stress and fertilizer stress had significant effect on all traits. However, the interaction was significant only for number of seeds per head, seed yield and oil percentage. The highest traits among levels of water stress were related to control and among the application of biofertilizer belonging to the treatment of combined application seed coated and topdress, which thousand grain weight 74.42 and 67.25 g, head diameter 17.67 and 16.74 cm, biological yield 10596.74 kg. ha^-1 and 10165.43 and oil yield 1318.55 and 1216.73 kg. ha^-1 respectively. However, the highest number of seeds per head (950.51 number), seed yield (3451.23 kg. ha^-1) and oil percent (47.68 %) were obtained in combined treatments of non stress and application seed coated with topdress. The effect of water deficit stress on the reproductive stage was significantly more than the vegetative stage. Biofertilizer treatment as seed coated has no significant difference with combined application seed coated and topdress. Which indicates that biofertilizer (Phosphate Fertile 2) makes better use of seed coated. The result of the experiment showed that with the use of biophosphate to form seed coated achieved optimal yield in sunflower cultivars of Euroflour and under water deficit stress, decreasing the intensity of stress on the traits under study.
 

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In order to investigate the possibility of reducing the quantitative and qualitative damage of rapeseed Neptune cultivar in water deficit tension conditions by applying foliar application of salicylic acid and micronutrients in Khorramabad climate, an experiment was conducted as a factorial split plot in a randomized complete blocks statistical design with three replications at Faculty of Agriculture Lorestan University in cropping year 2016-2017. Irrigation at two levels of 20 and 70 percent of field capacity depletion was applied in the main plots and composition of micronutrients (B1 non- consumption and B2 foliar application with a ratio of 2 per thousand) and salicylic acid factor (concentrations of zero, 0.5, 1 and 1.5 millimolar) were compared in sub-plots. The results showed that the simple effects of water deficit tension, foliar application of micronutrients fertilizer and salicylic acid on all tested traits were significant. Also, the triple interaction on number of pods per plant, seed yield, oil yield and carotenoids was significant. The highest seed yield and oil yield were obtained with an average of 4424.7 and 2036.7 kilogram per hectare in the optimal irrigation treatment and foliar application of micronutrients fertilizer with a concentration of 2 per thousand and salicylic acid with a concentration of 1.5 millimolar, respectively. Water deficit tension decreased total chlorophyll, carotenoid, number of stalks per plant, number of seeds per stalk, one-thousand seed weight, grain yield, oil percentage and oil yield by 14, 28, 20, 17, 27, 42, 42, 14 and 49 percent, respectively. However, foliar application of salicylic acid and micronutrients, while increasing resistance to water deficit tension conditions, could improve plant growth and physiological characteristics, including increasing photosynthetic pigments, provide favorable conditions for better plant growth and by increasing the grain yield components, finally increase the grain yield by 29 percent (1281.5 kilogram per hectare)in non tension conditions and 36 percent (1064.9 kilogram per hectare) in tension conditions. Therefore, a triple fertimix micronutrient fertilizer (iron + zinc + manganese) with a concentration of 2 per thousand is recommended along with a concentration of 1.5 millimolar of salicylic acid to reduce the negative effects of water deficit tension and achieving acceptable yield.