CROP PHYSIOLOGY
Year:2019 | Volume:11 | Issue:3 (43)|Papers Count:8

In order to investigate and compare the effect of external application of hormonal treatments on some biochemical characteristics and one-thousand grain weight in three wheat cultivars in terms of degree of tolerance to water deficit period including Pishtaz (tolerant), Sabalan (semi-tolerant) and Gaspard (susceptible) under drought tension during onset booting origin, the pot experiment as factorial design with four replications was conducted in Yazd University in 2015. Treatments included cultivar factor at three levels, drought tension at two levels (100% field capacity or control, 50% or drought tension) and hormone application at four levels without hormone, Kinetin (100 microMolar concentration), 24-epibrasinolide (1 microMolar) and their interaction. All analyzes were performed on the flag leaf. Drought incidence resulted in the most significant decrease in chlorophyll a, b, a + b content, chlorophyll a/b ratio, carotenoid, protein and one-thousand grain weight in susceptible cultivar (Gaspard). The highest significant increase in abscisic acid, soluble sugars, proline and soluble sugars / starch ratio was observed in tolerant cultivar. Among the hormonal treatments, 24epibrasinolide had the most significant increase in intrinsic abscisic acid and soluble sugars / starch ratios, and the interaction of Kinetin and 24-epibrasinolide had the highest increase in pigment content, proline and protein content, as well as one-thousand grain weight during drought incidence particularly in tolerant cultivar (Pishtaz). The results of the present research showed that the effect of hormonal treatments on biochemical indices was more than their effect on one-thousand grain weight. Overall, the interaction treatment of Kinetin and 24-epibrasinolide had more effect on biochemical indices and one-thousand grain weight than individual hormone treatments. Pishtaz (tolerant) cultivar has benefited more from hormone treatments to better withstand the dehydration period.

Due to the necessity of saving water resources, in order to investigate the new maize cultivars to reduce the negative effect of water shortage, a split plot experiment based on randomized complete blocks design with three replications at Arak Islamic Azad University in 2015-2016 and 2016-2017 cropping years was carried out. Different irrigation treatments including I1 (7 days, area custom), I2 (10 days), I3 (12 days), I4 (14 days) once to the end of the period, plant irrigation cut off after seedling establishment from 3 to 7 leaf stage and after that irrigation interval I5 (10 days), I6 (12 days) and I7 (14 days) were compared once in the main plots and four maize cultivars including single cross 704 control, 703, 705 and 706 in the sub plots. Irrigation treatments and maize hybrids had significant effect on yield and physiological parameters. Decreasing irrigation level decreased yield, relative water content and chlorophyll concentration in leaves compared to control treatment. In irrigation interval interaction and cultivars, single cross 703 showed the highest mean to maintain yield and growth indices in irrigation intervals I1 to I3, while single cross 705 showed superiority to other cultivars in irrigation intervals I4 to I7. In all irrigation periods, single cross 704 was recorded with the lowest power compared to other cultivars. The highest water use efficiency was related to 705 cultivar in I5 irrigation interval with 54. 39 percent superiority compared to control irrigation interval treatment and 704 cultivar.

In order to investigate the effect of nitrogen fertilizer application and Cycocel growth regulator on nitrogen utilization efficiency, some physiological characteristics and grain yield of rice, a factorial experiment was conducted in a randomized complete blocks design with three replications at Soume-esara Gilan in Province in 2013-2014. Factors investigated included the amount of nitrogen fertilizer at four levels (no nitrogen as control, application 100, 150 and 200 kilogram net nitrogen per hectare) from urea source and four levels of cycocel (no use, 0. 8, 1. 6 and 2. 4 liter per hectare). The results showed that foliar application of 4. 2 liters per hectare of cycocel and application of 200 kilgram nitrogen per hectare, increased grain filling rate, effective grain length, grain length and effective grain filling period, number of grains per panicle and one-thousand grain weight. The highest dry matter transfer from stem and whole plant were 91. 57 and 6. 114 gram per meter respectively, and the highest share of remobilization and participation of stem reserves in grain yield, respectively, was 91. 47 and 04. 27 percent in the absence of nitrogen fertilizer application conditions and foliar application of 4. 2 liter per hectare of cycocel. The highest grain yield was obtained in the application of 200 kilogram per hectare nitrogen and the least was in the absence of nitrogen application. The highest nitrogen use efficiency was related to 100 kilogram nitrogen per hectare and was allocated to the application of 200 kilogram per hectare of nitrogen fertilizer. The highest nitrogen use efficiency was allocated to the use of 4. 2 liters per hectare of cycocel and the lowest to no use of cycocel. Foliar application of 0. 8., 1. 6 and 2. 4 liters per hater of cycocel increased grain yield by 12. 47, 21. 68 and 32. 05 percent, respectively, than control. It seems that foliar application of 2. 4 liters per hectare of cycocel and application of 200 kilogram per hectare of nitrogen can be a suitable tool for increasing rice grain yield.

Selenium is a non-metallic element that improves the growth and physiological traits of plants by affecting the plant growth and the presence in antioxidant systems. For this purpose, an experiment was conducted in a randomized complete blocks design with split plot design with three replications during two cropping years 2013-94 and 2014-95 at research farm of Karaj Seed and Plant Improvement Research Institute. Foliar application of selenium (from selenate sodium source) in main plots in two levels control (no foliar application) and 30 gram per liter foliar application in two preflowering stages and six autumn type rapeseed genotypes in sub-plots were compared. The effect of year, foliar application and genotype on leaf proline content, soluble carbohydrate, photosynthetic pigments content, selenium content and seed oil and grain yield were significant. Selenium application increased proline (68. 6 percent), carbohydrate (26. 7 percent ), chlorophyll a (65. 8 percent), total chlorophyll (04. 7 percent), grain selenium 87. 79 percent), seed oil (89. 0 percent) and grain yield (01. 8 percent) were compared with control treatment. In 2013-2014 cropping year, the proline content of leaf was significantly higher and equal to 33. 69 percent higher than in 2014-2015. The highest oil content and grain yield were observed in 102SW genotype with average of 7. 43 percent and 6. 2060 kilogram per hectare, respectively. In general, the obtained results showed that cultivation of 102SW and Elvis genotypes under selenium foliar application conditions, resulted in optimum oil content and grain yield, which is recommended for the study area.

In order to investigate the effect of fertilizer application with chemical fertilizers and iron and zinc nano-Chelates on chlorophyll concentration, light utilization efficiency and grain yield of two bread wheat cultivars, a factorial experiment based on a randomized complete blocks design with three replications was conducted in the field research of Jihad Agriculture Center of Zarrin Abad Center during 2016-2017 cropping year. Experimental factors included seven levels of spraying (control, spraying with iron chelate, iron nano chelate, zinc sulfate, zinc nano chelate, iron chelate + zinc sulfate and nano iron chelate + zinc nano chelate) and second factor two wheat cultivars (Chamran and Koohdasht). The results showed that foliar application with iron fertilizers and zinc sulfate had a significant effect on chlorophyll concentration and maximum leaf area index at 1 and 5 percent probability levels, respectively. The maximum leaf area index at the statistical level of 1 percent in Koohdasht cultivar was 21. 7 percent higher than Chamran cultivar. Foliar application with nanochelates of iron with zinc nano chelate has reached the maximum dry matter accumulation (782 gram per meter square). The least dry matter was obtained at 681 gram per meter square in control plants (non-spraying). In Chamran cultivar, the maximum amount of radiation use efficiency was 30. 2 gram per mega Joule with the use of iron nano chelate, which was 27. 10 percent more than control plant. The highest amount of light consumption in Koohdasht cultivar (45. 2 gram per mega Joule) under zinc sulfate + iron chelate foliar application and its lowest value (08. 2 gram per mega Joule) was obtained in control plants. Spraying with nano chelate zinc + nano chelate of iron and iron chelate + zinc sulfate increased the grain yield of wheat cultivar Chamran by 44. 27 and 95. 15 percent, respectively, compared to control treatment. In Koohdasht cultivar, zinc and iron nano chelate had no significant effect on grain wheat agronomy in Koohdasht cultivar.

In order to investigate the effect of water deficit tension and titanium dioxide nanoparticle spraying on maize yield and activity of some sweet corn antioxidant enzymes, the present experiment was conducted as split plots in a randomized complete blocks design with three replications at Islamic Azad University Research Station, Tabriz Branch was carried out in 2017. Experimental treatments were water deficit tension at three levels of 50, 75 and 100 percent of available moisture and spraying with titanium dioxide nanoparticles at four levels of zero, 0. 01, 0. 03 and 0. 05 percent. The results showed that the effect of water deficit tension on hydrogen peroxide enzyme activity, relative humidity content, ear yield and ascorbic peroxidase was significant. Also, the effect of foliar application with nano titanium dioxide was significant on all studied traits and on the interaction of water deficit tension and foliar application with nano dioxide except for relative humidity content in other studied traits. Application of nano titanium dioxide at 0. 01 percent concentration in all treatments increased catalase, ascorbate peroxidase and hydrogen peroxide enzymes but foliar application of nano dioxide at 50 percent humidity had the highest activity of catalase enzymes., Ascorbate peroxidase had the lowest amount of hydrogen peroxide. Also, foliar application of 0. 01 percent nano titanium dioxide under complete irrigation conditions compared to non-foliar application of this compound under conditions of 50 percent available moisture and control increased maize yield by 58 and 1. 8 percent, respectively. Overall, foliar application of 0. 01 percent nano titanium dioxide concentration in water deficit tension conditions increased the activity of enzymes related to reducing the destructive effect of tension and eventually resulted in higher yield of maize under similar conditions and no use of this compound.

In order to evaluate the effect of heat tension and water restriction on yield and components yield of wheat cultivars, the present experiment was conducted as split plots based on randomized complete blocks design with four replications at Khuzestan Agricultural Research Center in two years in (20162017). Main plots included control: planting on recommended date and normal conditions, planting on recommended date and and irrigation cut off after pollination and planting with a delay of one month from the recommended planting date and having normal conditions and sub plot consisted of three wheat genotypes Chamran2, Aflak and Khalil. The results showed that drought and heat and water restriction effect reduced the yield and its components and grain filling period is heavily influenced by heat tension for all cultivars. In general, Khalil cultivar with the most grain yield (3582 kilogram per hectare) and one-thousand grain weight (3. 34 gram) was superior to other cultivars under tension of water and heat restriction. Grain yield of Chamran 2 cultivar revealed a significant decrease in water restriction and heat tension conditions and in this situation it is not recommended. Compared to the other two cultivars, Khalil had the highest grain yield and one-thousand grain weight under drought tension conditions was more stable and is suitable for cultivation under such conditions.

Acidic modifiers are common methods in high pH soils to increase solubility of nutrients. In order to investigate the possibility of reducing the soil alkalinity and increasing the solubility of nutrients, this experiment was conducted based on factorial in a randomized complete block design with three replications. The factors including three levels of zero, 250 and 500 kg/ha sulfur sulfate and three levels of zero, 5 and 10 kg/ha thiobacillus bio-fertilizer that performed in three replicates in the Elahi village located in north of Ahvaz in 2017-18. The results showed that the effect of sulfur fertilizer and thiobacillus on number of spikes per square meter, grain number per spike, 1000-grain weight, grain yield, biological yield, harvest index and protein percentage were significant at 1% probability level. The interaction between sulfur and thiobacillus fertilizers on biological yield at 1% and harvest index at 5% probability level was significant. The results of mean comparisons showed that grain yield and protein percentage increased with change in thiobacillus and sulfur content and was statistically different at different levels of treatments. The maximum grain yield was obtained from 500 kg/ha sulfur treatment and 10 kg/ha thiobacillus by 5663 and 5077 kg/ha, respectively, while the minimum grain yield was observed under non-application of sulfur by 3668 kg/ha and non-application of thiobacillus by 4329 kg/ha. The maximum protein content was under 500 kg/ha sulfur and 10 kg/ha thiobacillus by 13. 2% and 12. 7% and the minimum was in non-application of sulfur by 10. 8% and non-application of thiobacillus by 11. 6%. In general, the results of the experiment showed that under sulfur and thiobacillus application, it is possible to increase the quantitative and qualitative of yield in wheat. In this experiment, the best result was obtained under 500 kg/ha of sulfur and 10 kg/ha of thiobacillus, which could be considered and recommended by farmers and researchers.