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Showing 6 results for Drought
Esmaeil Gholinezhad, Volume 1, Issue 1 (9-2014)
Abstract
In order to investigate the effects of water deficit stress effects, different rates of nitrogen and plant density on remobilization, current photosynthesis and grain yield in oily sunflower var. Iroflor, an experiment was carried out in field Agriculture and Research center of West-Azerbaijan during 2011 and 2012 cropping seasons. The experimental was conducted as split-split-plot base on Randomized Complete Block Design (RCB) with 3 replications. The main factor was consisted irrigation treatment including optimum irrigation, moderate stress and sever stress which irrigation was done after depletion of 50%, 70% and 90% of available water, respectively. Three nitrogen levels of 100, 160 and 220 kg N haG1 were considered as sub plots and sub-sub plots consisted of three plant populations of 5.55, 6.66 and 8.33 plants m2. The results of combined analyzes showed that severe drought stress reduced the grain yield by 60% compared to the optimum irrigation condition. Comparison of two-year-mean revealed that severe drought stress in compared with optimum irrigation dry matter remobilization rate decreased about 30 percent. Also, severe drought stress led to 35% reduction of current photosynthesis efficiency in compared with optimum irrigation. In each level of nitrogen fertilizer, increasing plant population led to increase contribution of remobilization but current photosynthesis contribution decreased. Therefore, due to reduction of current photosynthesis rate in severe drought stress condition, contribution of current photosynthesis decreased so that increasing of (contribution of, deleted) remobilization contribution prevented reduction of seed yield.
Hadi Estiri, Mohammad Armin, Ismaeal Filehkesh, Volume 1, Issue 1 (9-2014)
Abstract
A field experiments was conducted at Sabzevar Agriculture & Natural Resources A field experiments was conducted to study the effect of zinc sulfate foliar application on yield and yield components of sunflower, Haysun-25 cultivar (Helianthus annuus L.) under drought stress at Sabzevar Agriculture & Natural Resources research center. This experiment was carried out (conducted, deleted) as split plot based on randomized complete block (RCB) design that main and subplot factors were drought stress levels [Non-stress, Moderate and High drought stress (6, 12 and 18 day’s irrigation interval, respectively] and foliar zinc applications (0, 5, 10 and 15‰), respectively. Foliar application of zinc was performed in 6 to 8 leaf stage of sunflower. Plant height, seeds per head, hollowness percentage seeds, 1000 seed weight, grain yield and biological yield were significantly affected by drought stress. Severe drought stress decreased plant height, seeds per head, 1000 seed weight and economic yield and increased percentage of empty seeds. The highest yield and yield components were related to foliar application with 15‰ concentration of zinc sulfate and the lowest one was related to the control. However, yield response to zinc sulfate foliar application was more in non-stress condition, but zinc sulfate with 15‰ led to decrease of negative effects of drought stress. Overall, the highest yield was obtained by spraying with concentration of 15‰ zinc sulfate and non-stress condition.
Mehdi Ghaffari, Volume 1, Issue 1 (9-2014)
Abstract
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.
Seyed Ahmad Kalantar Ahmadi, Amir Husein Shirani Rad, Seyed Ataollah Siadat, Volume 1, Issue 2 (3-2015)
Abstract
In order to study the effect of limited-irrigation stress on canola cultivars, an experiment was conducted in 2007-2008 at the Safiabad agricultural research center. The design was a split plot in a completely randomized block basis with three replications. Main plots were consisted of 4 levels of limited-irrigation, irrigation based on 60 mm cumulative evaporation (Control), withholding irrigation in flowering stage, withholding irrigation in pod initiation and irrigation withholding in grain filling period, and subplots were 5 canola cultivars (Hyola308, Hyola330, Hyola401, Hyola420 and RGS003). The mean comparison of interaction showed that the highest (3155.55 kg.ha-1) grain yield appointed to Hyola420 cultivar in optimum irrigation (control treatment), and the lowest (1491.66 kg.ha-1) belonged to RGS003 cultivar at withholding irrigation in pod initiation period. The maximum (161.42) number of pods observed on Hyola330 cultivar at optimum irrigation (irrigation after 60 mm cumulative evaporation), and the minimum (78.1) ones appointed to RGS003 cultivar at withholding irrigation in pod initiation period. Results showed that there was no significant difference among withholding irrigation, cultivars and the interaction effect of them for oil content. By considering the results of this experiment, withholding irrigation at flowering, pod initiation and grain filling periods leads to decrease grain yield by 24.72%, 14.33% and 11%, respectively. Reduction of grain yield due to the withholding irrigation during flowering, podding and grain filling stages was along with a decrease in the number of pods per plant and thousand seed weight. By considering the results of experiment, withholding irrigation in flowering stage has to be avoided.
Moslem Alizadeh, Hamidreza Balouchi, Mohsen Movahhedi Dehnavi, Volume 1, Issue 2 (3-2015)
Abstract
In order to evaluate the foliar application of zinc sulfate and salicylic acid effects on morphology and yield of safflower Carthamus tinctorius L. ( cv. sofeh) under drought stress in Yasouj, a factorial experiment based on a randomized complete block design with four replications was conducted Yasouj University in 2012. The factors consist of three levels of drought stress, watering at 3 levels of consumption 10%, 30% and 60% of available water, respectively, as the levels of stress, mild stress and severe stress and foliar application in 5 levels, including control, salicylic acid (0.5, 1 and 1.5 Mm) and zinc sulfate (3 g l-1), respectively. The results showed that drought and foliar application interaction for number of heads, the number of fertile seeds per head, seed weight and yield were significant and other traits were non-significant. Drought stress reduced, but foliar application of zinc and salicylic acid increased the grain yield. The highest grain yield per plant at 30% and 60% moisture content were achieved by 0.5 Mm salicylic acid foliar applications. The highest grain yield in plant at 10% (FC) water availability was shown by zinc sulfate the foliar application. At all drought stress levels, the highest grain weight obtained by zinc sulfate foliar application and the highest fertile head number in 10 and 60 percent of water availability related the foliar applied concentration of 1Mm salicylic acid. The highest number of grains per head in 60% water availability belonged to 1.5Mm salicylic acid foliar applications.
Esmaeil Gholinezhad, Volume 3, Issue 1 (9-2016)
Abstract
In order to investigate the effects of mycorrhizal fungi on yield and water use efficiency of eight sesame (Sesamum indicum L.) genotypes in different levels of drought stress, an experiment was conducted using a factorial split plot with three replications in the research field of the Urmia agricultural high school in 2014. The main factor was consisted of different levels of irrigation as: normal irrigation (irrigation after 70 mm evaporation of the crop (ETc), moderate drought stress (irrigation after 90 mm ETc) and severe drought stress (irrigation after 110 mm ETc), and two species of mycorrhiza fungi (Glomus mosseae, Glomus intraradices) and non-inoculated (control). Sub plots consisted of eight landraces of sesame names Jiroft13, Zanjan Tarom Landrace, Moghan Landrace, several branches Naz, TC-25, TS-3, Darab 14 and Dashtestan 5. Results showed that the effect of irrigation, mycorrhiza fungi and genotypes on studying traits was significant. Mean comparisons showed that with increasing severity of drought stress, grain yield, biological yield, water use economic and biotic efficiencies decreased significantly. Severe drought stress reduced water use economic and biotic efficiencies about 62 and 49 percent, respectively. Using two species of mycorrhizal fungi (Glomus mosseae, Glomus intraradices) in comparison with non-inoculated (control) had significant effect on all studied traits. Inoculation with G. mosseae improved seed yield, biological yield and water use economic efficiency compared to control with 33, 42 and 33 percent, respectively. Moghan landrace and Zanjan Tarom landrace based on yield and water use efficiency, had superiority on other landraces. Mycorrhiza led to improve yield of landraces and in severe drought stress conditions, sesame plants showed a higher mycorrhizal dependency.
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