CROP PHYSIOLOGY
Year:2021 | Volume:12 | Issue:4 (48)|Papers Count:10

Rapeseed is one of the most important oil crops in the world and Iran and water shortage is one of the most important factors limiting rapeseed growth and development in Iran. Plant growth in the early stages and its proper establishment can be considered as a selection criterion in the plant breeding. Since germination rate and percentage and growth-related traits are directly involved in the plant yielding, direct selection for growth traits under tension conditions is important in the identification of tolerant genotypes. A factorial experiment was conducted with four levels of osmotic tension (zero,-0. 3,-0. 5 and-1 bar) obtained from different concentrations of polyethylene glycol (zero, 20, 15 and 10 percent) and seeds of three rapeseed cultivars in a completely randomized design with three replications at the laboratory of Kerman Graduate University of Industrial and Advanced Technology for nine months in 2018-2019. After the seed’ s disinfection, they were planted in the petri dishes and the drought treatments were applied on them. The interaction of genotype and drought treatments was significant for all evaluated traits except for stem height trait at one percent probability level. Statistical analysis and mean comparisons showed that in the applied moisture tension the amount of germination percentage, seedling growth, root growth, photosynthetic pigments and the amount of protein decreased and the amount of proline and antioxidant enzymes increased. The highest amount of germination percentage (78 percent), root length (5. 78 millimeter), proline content (1. 33) and polyphenol oxidase enzyme (0. 063) were observed in Agamax cultivar, the highest amount of fresh (1. 83) and dry (0. 927) stem weight, chlorophyll a (9. 007), chlorophyll b (2. 56), total chlorophyll (10. 9), carotenoids (2. 64) and soluble sugar (0. 65) was evaluated in Traper cultivar and the highest amount of soluble protein (0. 714) and catalase enzyme (0. 008) in Hayola 61 cultivar. By applying sever osmotic tension, Agamex cultivar showed a 25 percent reduction in germination rate and 63 percent in soluble proteins content, increasing 2. 3 times more proline content, 1. 54 times more soluble sugar content, 33 percent polyphenol oxidase and 67 percent catalase enzymes in compare to normal moisture conditions and showed better response than Hayola 61 and Trapper cultivars.

In the present research in order to investigate the effect of seed pretreatment on quantitative and qualitative characteristics of quinoa seedlings under drought tension, a factorial experiment was conducted in a completely randomized statistical design with three replications in the research greenhouse of Faculty of Agricultural Sciences of Shahed University in 2019. In this experiment, seed pretreatment was performed at two levels of hydro-priming for 12 hours and bio-priming with bacteria (Bacillus subtilis) for 24 hours and drought tension at five levels of 0,-0. 5,-1,-1. 5 and-2 Megapascals with Polyethylene glycol. The results showed the effect of pretreatment on all investigated traits except for malondialdehyde content and membrane stability was significant. Application of growth-promoting bacteria led to improvement of quinoa seedling indices such as fresh weight content of shoots (29 gram), chlorophyll content (40. 65 microgram per gram), carotenoid (2179. 3 microgram per gram), activity of superoxide dismutase enzymes (16. 60 milligram per protein) and catalase (3. 07 milligram per protein), total phenol (52 mol per gram), flavonoids content (62. 65 mol per gram). Increased drought tension resulted in a decrease in shoot fresh weight, carotenoid content, total sugar and protein content, but increased content of chlorophyll, proline, total phenol, flavonoids and catalase enzyme activity rate under drought tension conditions. Also, the dual interaction of pretreatment in drought tension on chlorophyll a content was significant and the highest chlorophyll content (28. 05 microgram per gram) was obtained at-2 Megapascals and bio-priming tension. Therefore, biopriming with bacteria is recommended to achieve the highest amount of fresh weight of shoots, enzymatic and non-enzymatic antioxidants of quinoa.

The present research was conducted to investigate the effect of different irrigation regimes on growth physiological characteristics of corn hybrids according to split plot experiment based on randomized complete blocks design with three replications in spring and summer during 2014-2015 and 2015-2016 cropping years. The main factor included four different irrigation regimes and the sub factor included single cross 704, single cross 701 (Karun) and single cross 616 (Mobin) cultivars. The results of statistical analysis of data showed that in spring and summer cultivation, the effect of different irrigation regimes and hybrid on total dry matter and leaf area index, crop growth rate and net uptake rate, relative growth rate and leaf area durability were significant. The results of comparing the means showed that I2 treatment (irrigation of a furrow during the stages of 4 to 12 leaves and 12 leaves until the emergence of cob silk and conventional irrigation from the emergence of cob silk to maturity) had the lowest total dry matter, leaf area index, crop growth rate, net uptake rate, relative growth rate and leaf area durability and allocated the highest decrease in measured traits compared to treatment I1 or control (conventional irrigation). Therefore, low irrigation application is not recommended in the early and middle stages of growth (four leaves until the emergence of cob silk). The superiority of single cross 704 over other hybrids in agraphiological traits can be related to higher yield potential, early maturity and greater adaptation to environmental conditions. The results of comparing spring and summer cultivation showed significant difference in the measured traits (except for net uptake rate). Applying low irrigation in treatment I3 (irrigation one among furrows in 12-leaf stage until emergence of cob silk) had the least decrease in growth indices (compared to other low irrigation treatments) compared to conventional irrigation. Therefore, full irrigation in the stage of emergence of cob silk until seed maturity and low irrigation in the middle stages of growth (12 leaves until the emergence of silk leaves) is recommended as the most appropriate option to deal with limited water resources.

Dehydration and deficiency of nitrogen fertilizer are important factors in reducing the quantitative and qualitative yield of wheat. The use of appropriate cultivars and some agricultural operations can help reduce the damage of these factors. In order to investigate the effect of irrigation cut and different amonts of nitrogen fertilizer on some quantitative, qualitative characteristics and redistribution rate of photosynthetic materials stored in durum wheat plant, the present experiment was carried out in a statistical form of split-split plots in a randomized complete blocks design in three replications in Ramhormoz during 2013-14 cropping year. Experimental factors include three levels of irrigation cut in the spike stage, at the beginning of the seeding stage and full irrigation in the main plots, four levels of nitrogen (zero, 60, 120 and 180 kilogram per hectare of pure nitrogen from the urea source) in the subplots and two durum wheat cultivars Yavaros and Behrang were in the sub-sub plots. The results showed that irrigation cut and nitrogen fertilizer content treatments had a significant effect on quantitative, qualitative and redistribution rate traits of photosynthetic materials and there was also a significant difference between investigated wheat cultivars in terms of growth response to irrigation cut and nitrogen fertilizer content. The highest grain yield (3587. 3587 kilogram per hectare), harvesting index and redistribution of total shoot (0. 96 gram per plant) in Behrang cultivar with consumption of 180 kilogram per hectare of nitrogen fertilizer in full irrigation was obtained. In general, it can be said that reducing the effects of irrigation cut by balanced selection of nitrogen fertilizer and the correct choice of cultivar (Yavarus) can be a good opportunity to make optimal use of low irrigation techniques to combat water shortage.

n order to investigate the effect of drought tension, nitrogen supply source and planting density on agronomic and physiological characteristics of sunflower cultivar Haissan in the north of Golestan province, an experiment was conducted in 2015 and 2016. The present research was performed in the form of split-split plots in randomized complete blocks design with three replications and 27 treatments. The main factor included drought treatment with three rainfed levels, one irrigation stage (cultivation stage) and three irrigation stages (cultivation, flowering, grain filling stages). The subfactor included three levels of nitrogen supply (100 percent urea, 50 percent nitroxin and 100 percent nitroxin) and plant density as a sub-sub-treatment had three levels of 50, 75 and 100 thousand plants per hectare that were randomly placed in main and sub-plots and sub-sub-plots. The results showed that the effect of drought tension, nitrogen supply source and plant density on plant height, seed diameter, number of seeds, one-thousand grain, oil percentage, harvest index, biological yield and economic yield were significant at one percent probability level. The highest plant height, head diameter, number of seeds per head, one-thousand grain weight, oil percentage, harvest index, biological yield and economic yield were obtained in the treatment of three irrigation stages. Application of treatment (50 percent nitroxin and 50 percent urea) as nitrogen supply sources improved all traits. Based on the obtained results of the present research, three stages of irrigation and application of 50 percent nitroxin and 50 percent urea as a source of nitrogen supply and increasing plant density are recommended for proper production and yield.

In order to investigate the environmental biological control of soybean charcoal rot disease by using the mutated formulation of Trichoderma Harzyanum with gamma ray, factorial field experiments in a completely randomized block design for morphological traits was performed in a farm located in Islamshahr in 2018-2019. The experiment consisted of 12 treatments including control, application of commercial biological fungicide of Trichoderma, soybean and inoculation of mutant and non-mutant Trichoderma fungi in powder and granules. The results showed that the effect of treatments was significant for all soybean morphological traits. The use of Trichoderma fungi treatments increased the quantitative amount of morphological traits such as grain yield, total dry weight, number of pods per plant, number of sub-branches, plant height, number of seeds per pod, one thousand seed weight, number of seeds per plant, harvest index, protein content and oil content, so that the highest average grain yield belonged to granular mutant Trichoderma and powder mutant Trichoderma treatments with averages of 3531. 25 and 3527. 5 kilogram per hectare, respectively. The results also showed that the interaction of formulation and pathogen in the number of pods per plant in the treatments of granular mutant Trichoderma and pathogenic powder mutant Trichoderma with 47 pods had the highest rate.

The present research was conducted to investigate the effect of sulfur on physiological traits of promising line of L17 canola at Mazandaran Agricultural and Natural Resources Research and Education Center-Baye Kola Agricultural Research Station on the basis of randomized complete blocks design with three replications in 2018-2019 cropping year. In this research, photosynthetic pigments content, activity pf some antioxidant enzymes, oil content, protein content, oil yield and protein yield were measured. The data results showed that the effect of all sulfur treatments on the investigated traits were significant at one percent probability level. The results of mean comparisons of the investigated traits exhibited that using the amounts of 200 and 300 kilogram per hectare sulfur had the highest effect on the above-mentioned traits. In addition, the correlation test results indicated that oil yield showed the significant and positive correlation coefficients with the traits of protein yield (0. 999), peroxidase enzyme activity (0. 894), chlorophyll a (0. 861), total chlorophyll (0. 849), oil content (0. 841), chlorophyll b (0. 805), superoxide dismutase enzyme activity rate (0. 801) and carotenoid (0. 759), respectively. Thus, according to the results, it seems that the combination use of sulfur accompanied by inoculation with Thiobacillus bacteria could be considered as a method for improving the qualitative traits of promising line of L17 canola.

Water deficiency is one of the most important factors limiting canola production in arid and semiarid regions in Iran. In order to investigate the effect of drought tension through irrigation cut at the end of the season and application of vermicompost on some morphophysiological characteristics of rapeseed, a factorial-split experiment in the form of a randomized complete blocks design with three replications was carried out at Karaj Seed and Plant Improvement Research Institute in 2015 and 2016. Experimental factors include irrigation regime at three levels (full irrigation during the season, irrigation cut from the podding stage to the end of the season and irrigation cut from the flowering stage to the end of the season) and vermicompost at two levels (non-application and application of 20 tons per hectare) as the factorial in the main plot and genotype at 6 levels (RGS003, Zafar, Julius, Jerry, Zabol10 and Hyola4815) in the subplots. The results of analysis of variance showed that the effect of year, irrigation, vermicompost and cultivar on the measured traits was significant at the level of 1 percent probability. Mean comparison showed that the plants in the second year had higher height, stem diameter, number of pods and chlorophyll content than the first year, but the amount of soluble carbohydrates, stomata resistance and canopy temperature of the plant in the first year was higher than the second year. The highest height, number of pods, leaf chlorophyll and stem diameter belonged to Zafar cultivar under normal irrigation conditions and the lowest value was observed in Zabol10 cultivar under irrigation cut conditions from flowering stage. Plant height, number of pods, stomatal resistance and canola leaf chlorophyll in vermicompost application conditions were higher than non-vermicompost application conditions, but the values of soluble carbohydrates and canopy temperature were higher in vermicompost application conditions. The highest amount of soluble carbohydrates in leaves belonged to Zabol10 cultivar in the conditions of irrigation cut from flowering stage and the lowest amount of soluble carbohydrates in Zafar cultivar was observed in normal irrigation conditions. The highest stomatal resistance belonged to Zafar cultivars in irrigation cut-off treatment at flowering stage and the lowest in Zabol10 cultivar in normal irrigation conditions. The lowest and highest canopy temperatures were observed in normal irrigation conditions and irrigation cut from flowering stage, respectively.

Lack of moisture and calcareous of agricultural soils are the main factors reducing the efficiency of absorption of micronutrients such as iron and zinc from soil solution and reducing the yield of crops in most rainfed areas. Therefore, in order to evaluate the effect of foliar application of different concentrations of ferrous and zinc sulphate in rainfed conditions on grain yield and some physiological characteristics of Camelina, the present research was conducted as a factorial experiment in a randomized complete blocks design with three replications in Kermanshah during the cropping year 2017-2018. Experimental treatments include foliar application of micronutrients at five levels (no foliar application and foliar application of iron sulphate and zinc at concentrations of 4 and 8 per thousand) and the factor of foliar application time at two levels at the beginning of vegetative growth and the time of Camelina flowering. Based on the obtained results, using foliar application treatments significantly increased the grain yield compared to the control treatment. The highest increase in grain and oil yield was related to the foliar application treatment of zinc at 8 per thousand level and at flowering time, which increased these traits from 1099 and 399 in control conditions to 1580 and 663 kilogram per hectare, respectively. Foliar application treatments and their application time caused a significant increase in other agronomic traits such as biomass yield, harvest index, number of pods per plant, number of seeds per pod, one thousand-seed weight, oil percentage and also physiological traits include concentrations of chlorophyll a and b, soluble sugars, proline and activity rate of superoxide dismutase antioxidant enzymes, peroxidase and catalase of leaves. But they had no significant effect on the content of carotenoids and total phenol. The highest additive effect on the investigated physiological treatment was related to the application of zinc sulphate at 4 per thousand levels at the beginning of generative growth, which increased the activity of antioxidant enzymes and catalase and superoxide dismutase by 85 percent on average.