جستجوی مقالات مرتبط با کلیدواژه « شاخص های رشدی » در نشریات گروه « زراعت »

Water deficit as one of the main environmental factors reduces plants yield around the world. Wheat is one of the most important cereal providing human’s food demand. Aegilops is a wild species belonging to the wheat family that can be used as a suitable germplasm to discover new genes to improve wheat tolerance to biotic and abiotic stresses in breeding programs. In this regard, 3 different species of Ae. Tauschii, Ae. Cylindrical, and Ae. Crassa , as well as wheat were cultivated under normal and water- deficit stress (FC = 25%). Morphological, physiological, biochemical, and growth indices were used to assess stress tolerance. Given the results, leaf length, width and area in plants under stress decreased sharply which the sensitive cultivar, Darya, showed the minimum value. Based on. biochemical analysis, under stress, peroxidase and catalase enzymes activities were increased either in wheat or in Aegilops, while ascorbate peroxidase decreased only in wheat in contrast to aegilops. A negative correlation was observed between catalase and ascorbate peroxidase under water-deficit stress. Among growth indices, wet and dry biomass rarely decreased in Cylindric species. According to multifactorial analysis, Ae. Cylindrical and Ae. Crassa species were more tolerant than wheat. Utilizing these could be useful to develop the tolerant cultivars to abiotic stress such as water- deficit.

Drought is one of the most important factors limiting growth and production in crops and therefore use of management methods to reduce the effects of drought is very important. Water deficit stress is one of the most important factors limiting the growth and survival of plants in arid and semi-arid regions of the world. Water is a major component of the fresh produce and significantly effects on weight and quality of plants. Also, water deficit may cause significant changes in the component yield and yield in plants. Iran with an average annual rainfall of 240 mm is included among arid and semi-arid regions of the world. Of the million hectares of cultivated region, only five millions are under irrigation because of intense water limitations. However, Iran is one of the world’s cowpea producers. Cowpea has been cultivated for many years in different parts of Iran. Therefore, high production and development of cowpea is important in coriander. This research was conducted to evaluate the effects of foliar application of glycine betaine (GB) and gibberellic acid (GA) on physiological characteristics, yield and yield components under drought stress conditions in cowpea.

To evaluate the effects of foliar application of glycine betaine (GB) and gibberellic acid (GA) on physiological characteristics, yield and yield components under drought stress conditions, a factorial split plot experiment based on randomized complete block design with three replications was conducted during the 2018 crop year. Experimental factors included irrigation regimes (50, 70 and 90 mm evaporation from Class A evaporation pan) in main plots and glycine betaine (no foliar application, 50 and 100 mM) and gibberellic acid (no foliar application, 60 and 120 ppm) were in factorial form in sub plots. Data were collected on relative water content, ion leakage, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, pod number per plant, seed number per pod, hundred seed weight, seed yield and biological yield.

The results of ANOVA indicated that the effects of irrigation regime, glycine betaine and gibberellic acid were significant for relative water content, ion leakage, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, pod number per plant, seed number per pod, hundred seed weight, seed yield and biological yield. The results of comparison of means showed that by increasing drought stress the traits of relative water content, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, pod number per plant, seed number per pod, hundred seed weight, seed yield and biological yield decreased but the ion leakage significantly increased. Nonetheless, exogenous application of glycine betaine and gibberellic acid increased relative water content, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, pod number per plant, seed number per pod, hundred seed weight, seed yield and biological yield but the ion leakage significantly decreased. It seems that glycine betaine and gibberellic acid improved the growth indices of cowpea by reducing the adverse effects of drought stress. Therefore, exogenous application of glycine betaine and gibberellic acid can be used as a useful method for improving drought tolerance in cowpea.

Generally, the results indicated that glycine betaine and gibberellic acid improved the growth indices of cowpea by reducing the adverse effects of drought stress. Therefore, exogenous application of glycine betaine and gibberellic acid can be used as a useful method for improving drought tolerance in cowpea. Also, the results showed that concentrations of 100 mM glycine betaine and 120 ppm gibberellic acid were more effective than other levels and induces more water stress tolerance in cowpea

Climate change (temperature, rainfall and flood patterns, etc.) has major and negative effects on agricultural production and water and land resources. Part of climate change is to reduce soil fertility (through erosion processes), increase the frequency of repeated pest attacks, reduce crop yields, and increase groundwater harvest periods by reducing water access. Zinc plays an essential role in the basic processes of plant life, namely cell division, stomata regulation and respiration. Apart from the increase in carbon dioxide emissions, high temperatures are also a major stressor that can lead to severe growth retardation and plant distribution. At higher concentrations, carbon dioxide increased photosynthetic carbon and increased organic matter, which in turn increased stem diameter of lentil plant (Shams, 2017) .

The composite experiment was performed as a factorial experiment in a completely randomized design with four replications. Irrigation at three levels (60, 80 and 100% of field capacity) as the first factor, foliar application of zinc sulfate fertilizer at two levels (no foliar application and 0.5 gl-1) as the second factor and environmental conditions at four levels (380_24, 380_31, 700_24 and 700_31 C/PPm (carbon dioxide) were the third factor. The studied traits were number of root nodes, root dry weight, stem height and diameter, number of leaves and grain yield. Data were analyzed using SAS 9.1 software and the mean of the treatments was compared with LSD test at 5% probability level.

Co-application of carbon dioxide, complete irrigation and complete irrigation and zinc sulfate increased the number of nodes. Increasing the concentration of carbon dioxide under severe drought stress increased root dry weight. Also, increasing the concentration of carbon dioxide under mild environmental stress caused plant height, diameter and grain yield. Increasing the concentration of carbon dioxide in full irrigation conditions increased the number of leaves. Increasing carbon dioxide increases water use, photosynthesis and net primary productivity by reducing stomatal conductance and transpiration, which ultimately increases biomass and yield.Application of zinc sulfate under full irrigation conditions increased the total grain yield by 17.1 g/plant. Positive role of zinc in chlorophyll synthesis, and performance of optical photosystems can increase growth indices. The use of zinc chelate due to the role of zinc in the activity of plant enzymes and metabolisms, including plant hormones (auxin) has increased chlorophyll activity and photosynthesis, which finally has increased grain yield in the plant. 

Increasing the concentration of carbon dioxide at lower temperatures and full irrigation and mild stress increased the majority of morphological traits. Also, application of zinc alone and with full irrigation increased some morphological traits and grain yield.

One of the strategies to increase the yield per unit area is to use suitable cultivars that are compatible with the climatic conditions of each region at the appropriate planting density, so that there is minimal competition between plants. Determining the appropriate crop density for rapeseed cultivars is very important and plays a decisive role in achieving the desired yield. Planting the crop for each plant and cultivar should be done in a density where the plant is well emerge, establish and in each stage of growth, has enough space to maximize the use of environmental factors and not face unfavorable conditions as much as possible.

This factorial experiment was conducted in a randomized complete block design in research farm of Gharakhil Agricultural Research Center, Ghaemshahr in 2017-2018. Treatments included: densities of 42, 66, 88, 114 and 133 plants m-2 and four rapeseed cultivars including: Hyola 401, Agamax, Hyola 4815 and Trapper which were performed in three replications. The evaluated traits included growth indices such as total dry matter content, leaf area index, crop growth rate, relative growth rate and net photosynthesis rate as well as yield.

The results showed that the interaction effect of cultivar and plant density was significantly different only for total dry matter and leaf area index. Maximum amount of total dry matter (910 g m-2) and leaf area index (3.53) was observed in Hayola 401 cultivar and density of 88 plants m-2 and minimum amount of total dry matter (393 g m-2) and leaf area index (2.26) was observed in Trapper cultivar at a density of 42 plants m-2. According to the results, the only simple effect of density was significant on crop growth rate, relative growth rate and net photosynthesis rate, according to which the highest crop growth rate with an average of 11.36 g m-2 d-1 was related to the density of 88 plants m-2 and the lowest one was obtained with an average of 5.91 g m-2 d-1 from a density of 42 plants m-2. Also, the maximum relative growth rate and net photosynthesis rate with an average of 0.0580 g g-1 d-1 and 3.49 g m-2 were obtained at a density of 88 plants m-2, respectively, and their minimum ones with an average of 0.0530 g g-1 d-1 and 2.99 g m-2 was seen from the density of 42 plants m-2. The highest grain yield with an average of 7031.8 kg ha-1 was related to Hayola 401 cultivar in a density of 88 plants m-2.

With increasing density of 42 plants m-2, dry matter production and leaf area increased; when the highest amount of dry matter and leaf area index in cultivar Hayola 401 in density of 88 plants m-2 had the best results and the highest rate of crop growth rate, relative growth rate and net photosynthesis rate were obtained at density of 88 plants m-2. Therefore, in low densities, due to the lack of complete canopy closure and low surface for radiation absorbance (leaves), dry matter production had decreased, while with increasing density more than 88 plants.m-2 due to increase intra specific competition, dry matter production and leaf area index decreased. Therefore, according to the results, planting cultivars Hayola 401 at a density of 88 plants m-2 is recommended to achieve high yields in the climate of Mazandaran.

Casing material is very important element for size and yield of mushroom. To study the replacement of peat moss by vermicompost from animal resource, this research was conducted with 3 replications as CRD basis. Treatments were T1: vermicompost+ perlite peat (1:1:2), T2: vermicompost+ perlite+ peat (2:1:1), T3: vermicompost+ perlite+ peat (3:0.5:0.5), T4: vermicompost+ peat (2:2), T5: vermicompost+ peat (1:3), T6: vermicompost+ peat (3:1), T7: vermicompost+ perlite (2:2), T8: control, T9: peat from Netherlands. After growth of mushroom, they separated in 3 groups: 1-mushroom with high quality (grade 1), 2-mushroom that have membrane abnormality and then leasers marketable than grade 1 (grade 2). 3-mushroom have defects and no marketable (grade 3). After harvesting, characters contain of yield and number of mushroom grade1, 2 and 3, protein percentage, humidity percentage, spore diameter measured. Results showed that T2 (vermicompost + perlite +peat) and T9 (Netherlands peat) had the most and least amount of mushroom grade1 respectively. T1and T7 had most and least of mushroom grade2. T3 had the most of protein content, also contained high amount of number and yield of mushroom, then this treat introduced the best treatment. It seems that for high addition character in vermicompost particles, can no use high amount of this treatment in replication with peat moss.

Nitrogen is one of the most abundant elements on earth and major essential for crop growth and development that is heavily used in modern agriculture to maximize yields. Among cereals, maize (Zea mays L.) is an important food and feed crop which ranks third after wheat and rice in the world. As N fertilizer costs remain relatively high and environmental concerns over excessive N application increase, the objectives of the present study were: (i) to compare maize hybrids growth and yield responses to N rates, (ii) to determine optimum N rate for maize grain yield production, (iii) to explore the physiological functions controlling maize growth and yield and (iv) to identify more effective physiological indices in maize grain production under N stress as well as potential condition.
Two field experiments were conducted in 2014 and 2015 at the Experimental Field of Kerman Agricultural and Natural Resources Research Center, Kerman, Iran. The experiment was laid out as a randomized complete block design with factorial arrangement of treatments and three replications. Four nitrogen rates (0, 92, 220 and 368 kg N ha-1) were applied to three maize hybrids (KSC 704, Maxima and TWC 604). Statistical analysis was done using SAS software (version 9.4).
Due to a significant lack of homogeneity of variance across the two years, data from the two years were treated as independent experiments and analyzed separately. Results showed that both N rates and hybrids had significant effect on growth indices and maize grain yield. The interaction between genotype and N rate was significant for grain yield in 2015 (P In this study, maize grain yield increased with N application up to 368 kg ha-1. However an economic evaluation is essential in order to optimum N fertilizer recommendation. LAI and LAID were known as key indices in maize grain yield formation. Nitrogen stress decreased maize grain yield mainly by reduction in LAI and LAID. Significant yield benefits were observed in KSC 704 and maxima compared to TWC 604 in both N stress and potential conditions.

In order to evaluate the tolerance of pistachio some cultivars to salinity a pot experiment was carried with 2 factors including cultivar and salinity in the year 2013. The cultivars were Ghazvini, Shah Pasand, Akbari, Khanjari, Jandaghi, Italiyayi, Fndoghi 48, Sabz Pesteh Tohg, Ahmad Aghayi, Rezaie Zood Res, Mousa Abadi, Ebarahimi, Kaleh Ghochi and Badami Zarand. The salinity was applied in five levels including 0, 2.4, 4.8, 7.2 and 9.6 g/l of sodium chloride with electrical conductivity equal to 0.5, 4.9, 9.8, 14.74 and 19.8 ds/m, respectively). Results revealed that in all of the studied cultivars, branch height, branch diameter, number of total leaves, percentage of green leaves, fresh and dry weight of leaves, shoots and root, relative humidity content, chlorophyll a, chlorophyll b and total chlorophylls, reduced when salinity level increased. But, percentage of necrotic leaves, percentage of downfall leave, root/shoot fresh and dry weight ratio, relative ionic percentage and cell membrane injury percentage were increased. Overall, Ghazvini was found to be the most tolerant cultivar to salinity stress (14.75 ds/m) among the evaluated cultivars. In contrast, Mousa Abadi and Rezaie Zood Res were the most sensitive cultivars to salinity stress.

In order to investigate the effect of planting density (50, 75 and 100 cm inter-row distance) and vermicompost (0, 5, 10 and 15 t.ha-1) on growth, qualitative and quantitative criteria of gooseberry (Physalis peruviana L., Solanaceae), an experiment was conducted as factorial based on complete randomized block design with three replications in University of Tehran, in 2013. Criteria such as leaf area, collar diameter, number of lateral branches per plant, plant height, fruit number and weight per plant, weight and diameter per fruit, calyx weight, total fruit yield, fruit marketable percentage, total marketable yield, plant dry weight and quality criteria such as pH, total soluble solids (TSS), titratable acidity (TA), vitamin C, antioxidant activity and fruit color indices were evaluated. Results showed that treatments significantly affected most measured growth and yield criteria in which application of 15 t.ha-1 vermicompost increased them compared to control (non-vermicompost application) in which fruit weight per plant, total fruit yield and marketable percentage were increased 37.31, 37.82 and 11.52 percent, respectively. Also, inter-row distance of 100 cm performed better for plant growth and yield criteria. Interaction effect of 100 cm planting density and 15 t.ha-1 vermicompost caused the highest number of fruit per plant and marketable yield. The highest amount of TA and antioxidant activity obtained by application of 15 and 10 t.ha-1 vermicompost, respectively and vitamin C, TA and TSS were increased in planting distance of 50, 75 and 75 cm inter-row distance, respectively.

Recent research studies show that the foliar application of methanol increases the growth of C₃ crops in arid regions. An experiment was carried out in a split plot based on randomized complete block design with three replications at the Research Station of Faculty of Agriculture, Ferdowsi University of Mashhad in spring 2010. Three irrigation levels (100, 75 and 50 percent of water requirement) and four foliar application levels of methanol (0, 20, 40 and 60 volumetric percent) formed the main and sub plots, respectively. Methanol was sprayed on chickpea shoots after pod stage in 3 times with a 10- day interval. The result showed that the effects of foliar application of methanol on physiological traits were significant. So that spraying of 60 volumetric percent of methanol affected physiological traits greater than other treatments and caused increasing in dry matter, leaf area index and crop growth rate while had no effect on relative growth rate. In drought stress treatment, leaf area index, cumulative dry weight and crop growth rate, relative growth rate were in their maximum amounts under adequate moisture treatment (control) compared with the drought stress conditions due to continued vegetative growth in control plants. In this experiment, the differences observed in the amount of dry matter accumulation and crop growth rate are mainly due to decreased leaf area index under drought stress conditions.

In this study، the ability of 32 rhizobium strains (26 strain of Sinorhizobium meliloti (SM))، 4 strains of Rhizobium leguminosarum biovar phaseoli (Rlp) and 2 salt tolerance strains of Rhizobium leguminosarum biovar viciae (Rlv) for use of ACC as individual nitrogen source in RMM media was evaluated. Based on the results، 25 strains were found positive for ACC-deaminse، and strains according to growth in the RMM media containing ACC were categorized into three groups of strong، medium، and weak. In the next step، in 2011 a series of greenhouse experiments were conducted for investigating the effectiveness of two strains from strong group (R281Rlp and R103Sm) and one strain from weak group (R29Sm) with control treatment، for the promotion of growth parameters of canola under the salinity levels of 0، 3، 6، and 9 ds/m in factorial format experiment as randomized complete block design with three replications. The Results showed that R281Rlp inoculation، even at higher salinity (9dS/m)، significantly increased wet and dry weight of root (32 and 62. 6%، respectively)، wet and dry weight of shoot (22 and 23. 5%، respectively)، height (49%) and nitrogen uptake (50%) compared to control treatment. Furthermore، at this level of salinity، R103Sm inoculation increased the uptake of Phosphorous up to 34. 5% compared to control. A positive correlation was observed between ACC-deaminase activity of bacterial isolates and plant growth parameters; especially root biomass، (Pearson correlation coefficients > 0. 82). These results revealed that the strains containing high ACC-deaminase activity were more successful in improving the growth parameters of canola seedling، which confirms that using of these strains may be suggested as a biologic alternative to the amelioration of increasingly saline stress.

In order to investigate the effect of supplemental irrigation and different levels of nitrogen fertilizer on growth indices of two durum wheat cultivars, this experiment was carried out as a randomized complete blocks design as sub-sub plots with three replications at the research farm of Agriculture College of Kermanshah Razi University in 2008-2009 cropping year. Treatments of this experiment included supplemental irrigation as the main factor at four levels and supplemental irrigation during booting, pollination and grain filling), net nitrogen fertilizer as a sub factor at four levels (without fertilizer, 50, 100 and 150 kilogram per hectare) and two durum wheat cultivars (Sardari and Cross Alborz) in sub-plot were placed. The measured traits including total dry matter, leaf area index, relative growth rate, net assimilation rate, crop growth rate, leaf dry matter, grain yield, grain length, grain diameter and peduncle length. The highest and lowest leaf area index was allocated to supplemental irrigation at pollination stages and durum conditions, respectively. With supplemental irrigation at booting stage, the maximum net assimilation rate was obtained, but supplemental irrigation caused the highest relative assimilation rate than control conditions (durum). Treatment of 150 kilogram per hectare produced the higher leaf area index and treatments 50 and 100 kilogram per hectare produced more net assimilation rate and relative growth rate. The highest grain yield was obtained in supplemental irrigation at pollination and booting time with 3622 and 3520 kilogram per hectare, respectively. Applying 50 kilogram per hectare of nitrogen caused the highest grain yield (3350 kilogram per hectare). Cross Alborz wheat cultivar (3378 kilogram per hectare) had more grain yield in comparison with Sardary cultivar (2982 kilogram per hectare). The maximum length and diameter of the grain was obtained with supplemental irrigation at anthesis stage, but the maximum length of pedankol was obtained by irrigation at stage of booting.

In order to evaluate the yield and physiological indices of 13 spring cultivars of rapeseed, an experiment was conducted in 2007 growing season at Agriculture and Natural Resources Research Station of Trogh, Mashhad. These cultivars were from three rapessed species, Brassica napus, Brassica rapa and Brassica juncea. The experimental design was randomized complete block with four replications. Results showed considerable differences among yield, TDM and LAI of cultivars. Seed yield of B. napus cultivars was more than that of B. rapa cultivars. With exception of RGR, cultivars of B. napus had more value of physiological indices than cultivars of B. rapa. A maximum TDM was obtained during growth season after 1105.3 GDD at pod filling stage. A maximum GAI was observed with receiving 744.7 GDD at flowering stage and after that lessening trend of GAI was gradually acquired with a mild slope. A maximum CGR was obtained after 867.9 GDD at end of flowering. Based on the results, it was concluded that TDM and LAI had more correlation coefficients than other physiological indices both within and among species