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Impact of three water deficit treatments in vegetative, flowering and grain filling stages along with optimum irrigation as control were evaluated on grain yield and agronomic characteristics of 8 sunflower cultivars (Hysun 33, Hysun 25, Farrokh, Record, Aravirski, Lakumka, Master and SHF 81-90) as a strip plot design with three replications in Khoy Agricultural and Natural Resources Research Station. Different water regimes had significant effect on growth period, plant height, stem and head diameter, seed yield and its component. Stem diameter, plant height and seed number per head were affected considerably by drought stress in vegetative stage, while head diameter by drought stress in flowering stage and growth period and seed weight by water deficit in seed filling stage. Water deficit in flowering and vegetative stages had the highest (38%) and lowest (25%) negative effect on grain yield, respectively, so flowering stage and vegetative stage established as the most sensitive and tolerant stages to water deficit, respectively. Farrokh hybrid with highest seed yield in different irrigation treatments (3686, 2856, 2256 and 2506 Kg/ha in control and water deficit in vegetative, flowering and grain filling stages, respectively) revealed as the most drought tolerant cultivator while Hysun33 lowest seed yield showed maximum drought sensitive.

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In order to comparison of antioxidant enzymes and proline roles in drought tolerance of rapeseed, an experiment was conducted at the research field of Yazd Agricultural and Natural Resources Research Center in 2011-2012. In this study, three commercial rapeseed genotypes (GKH2005, Opera and Okapi) were examined for response to irrigation treatments such as non-stress conditions (control) and withholding irrigation from stem elongation, flowering and silique formation stages in four separate experiments based on randomized complete block (RCB) design. The results indicated that proline accumulation, activity of catalase and proxidase enzyme and lipid peroxidation index (content of malondealdehyde) were higher in drought stress treatments, but these amounts were different in three rapeseed genotypes. Maximum activity of antioxidant enzymes and low content of malondealdehyde was observed in GKH2005 compared with others, in drought stress conditions. Between these genotypes, GKH2005 produced the highest seed yield under non-stress conditions and withholding irrigation from stem elongation, flowering and silique formation stages as 3110, 1450, 1773 and 2510 kg.ha-1, respectively. These results showed that role of antioxidant enzymes on reduction of lipid peroxidation and increasing the drought tolerance is more than proline. Also, an effective antioxidant system along with lower malondealdehyde and high silique number per secondary branch had the greatest role to productivity maintenance of Rapeseed under drought stress conditions

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In order to the evaluate the effect of planting dates on phenological traits, plant height, pods per plant and seed yield of rapeseed spring varieties, a split-split plot experiment based on randomized complete block design with four replications was conducted during 2 years at Agriculture Research Station of Baykola, Mazandaran, Iran. Treatments were planting dates (September 29, October 9, October 19, October 29 and November 8) as main plot and sub-plots were three cultivars ( Hyola401, Option500 and RGS003. All the traits were affected by planting date and variety. The mean values of seed yield of Hyola401, Option500 and RGS003 were 3274, 2898 and 3040 kg ha-1, respectively and Option500 and RGS003 had not statistically significant difference. Non significant interaction effects of planting dates and varieties for seed yield indicated that yield reduction of the varieties in late planting dates had similar trend and Hyola401 and Option500 had the most and the least seed yield, respectively. Seed yield reduction at late planting date was related to insufficient vegetative growth before flowering stage. Significant positive correlation between plant height and number of pods per plant was the main reason that in late planting date reduction of plant height imposed reduction of pods per plant and finally seed yield was decreased.

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In order to evaluate the effect of different nitrogen fertilizer levels on physiological traits, plant height, yield components, and seed yield of rapeseed genotypes a split-plot experiment based on a randomized complete block design with three replications was carried out at the Baykola Agriculture Research Station, Mazaandaran during 2010-11. Four levels of nitrogen, as urea fertilizer, including of 0, 70, 140 and 210 kg ha-1 were considered as main plots and four rapeseed genotypes including of L7, Zafar, RGS003 and Hyola401 were considered as subplots. The result of analysis of variance revealed that the traits, including number of days to flowering, number of days to end of flowering, number of days to maturity, plant height, siliques pods per plant, seeds per silique, seed yield and oil yield were significantly affected by nitrogen levels. Genotype effect was significant effect on all the traits except seeds per silique. Hyloa401 and Zafar respectively with 3831.2 and 3893.7 kg ha-1 of seed yield, and also 1638 and 1591 kg ha-1 of oil yield were classified at the same statistical group. Non significant interaction effects of nitrogen fertilizer application and genotypes were achieved for all of the studied traits, indicated that the trend of variation of these traits due to nitrogen levels were similar in all genotypes. A significant positive correlation of seed yield with the other studied the traits, except days to flowering, indicated that increasing of nitrogen level application made increasing of the traits and finally seed yield.

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In order to evaluate the effects of zinc foliar application, Rhizobium inculation and phosphorus solublizing bacteria on soybean cv. Katul an experiment was carried out as a factorial arrangement, in an RCBD with three replications at Deland (Golestan province) in 2015. The factors comprised of zinc spraying at three levels (without spraying, 1.5 and 3 g L^-1 zinc sulfate), inoculation with R. japanicum at two levels (with and without inoculation), and inoculated with phosphorus solublizing bacteria at two levels (with and without inoculation). The results revealed that the effects of phosphor solublizing bacteria were significant for plant height, stem diameter, number lateral branches, pod length, number of seeds per pod, number of pods per plant, 1000 seed weight, grain yield and oil per cent. Seed inoculation with Rhizobium significantly affected all trails studied with the exception of protein content and pod length, Zinc significantly affected grain yield, oil and protein content. The seed yield of psb treatment had significantly higher yield (2954 kg/ha) compared to seed yield (2752 kg/ha) of non-incolation. Also, spraying with zinc at 3g/li had significantly higher yield (2990 kg/ha) than that of without sprying yield (2648 kg/ha).