جستجوی مقالات مرتبط با کلیدواژه « phenology » در نشریات گروه « زراعت »

Planting date is considered to play a crucial role in decision-making processes of crop production and management, especially in the areas where plants are impacted by deleterious factors such as terminal cold and drought, early drought stress and extreme heat (Behdani & Jami Al-Ahmadi, 2008). In the studies conducted in different regions, delay in planting time in both autumn and spring resulted in decreases in grain, and oil yield, number of seeds per head, number of heads per plant, 1000-seed weight, plant height, number of leaves per plant, and dry weight of shoot (Solhe oskouei et al., 2016 ; Deltalab et al., 2011). Therefore, this experiment was performed to find the best winter sowing date for different cultivars and to investigate changes in grain yield, yield components and oil of safflower cultivars under delayed cultivation.

The experiment was carried out in a split plot arrangement based on randomized complete block design with three replications in two years, 2013 and 2014 at Zahak Agricultural and Natural Resources Research Station, Sistan and Baluchestan province. The main plot consisted of five sowing dates including: 21th Dec., 9th Jan., 29th Jan., 19th Feb. and 10th Mar. and the subplot was assigned to four cultivars; Golldasht, Padideh, Faraman, Gollmehr, which were independently randomized. In this study, yield characteristics and components of grain yield, agronomic and phonological traits in addition to grain oil content were investigated. Statistical analysis was performed using MSTAT-c software.Results &

The combined analysis of variance indicated significant effect of year, and cultivar on the all traits phenological, morphological, grain yield and its components as well as oil content. Goldasht and Faraman cultivars, at all the sowing dates, showed shorter time to physiological maturity. The highest mean of plant height (114 cm) was observed at the first sowing date (21th Dec.), which was 20% and 28% higher than the fourth (19th Feb.) and the fifth (10th Mar.) sowing dates, respectively. Padideh and Golmehr cultivars showed the highest plant height. Grain yield in the first year increased by 6% relative to the second year. The seed yield at the first sowing date (21th Dec.) was 1611 kg.ha -1, which was 16%, 24%, 37% and 44% greater than at the second (9th Jan.), the third (29th Jan.), the fourth (19th Feb) and the fifth (10 Mar.) sowing dates, respectively. A delayed planting from 21th Dec. declined the grain yield at a rate of 10 kg.ha-1 per day. The results for the triple interactive effects of cultivar × planting date × year showed that the highest grain yield was achieved in the first year × first sowing date (21th Dec. × the genotypes of Faraman and Goldasht with a mean yield of 2090 and 1758 kg.ha-1. Oil content was increased as the planting date was shifted from 21th Dec. to 10th Mar. The oil percentage at the first sowing date (21th Dec.) relative to the fifth sowing date (10th Mar,) increased by about 9% and among the cultivars, Padideh and Golmehr had 9% and 6% more oil content than Goldasht and Faraman, respectively. Seed yield showed the highest positive and significant correlation coefficient with number of boll per plant (r = 0.76 **), number of grain per boll (r = 0.75 **), and 1000-seed weight (r = 0. 47 **).

Losing the appropriate planting date for winter cultivation system of safflower, shifting from early January to early February, can lead to a compensatory seed yield production. In fact, at these dates, suitable environmental conditions facilitate increased duration of vegetative growth and the formation of higher yield components such as number of florets per boll, boll per plant and grain per boll as compared to late planting date. Among the studied cultivars, Faraman and Goldasht produced the highest grain yield at the all planting dates, maybe due to the higher number of grain per boll and 1000-seed weight. To achieve maximum grain and oil yield in winter safflower cultivation for the conditions of Sistan region, sowing from early January (first date 21th Dec.) to late January (second date (9th Jan) using early maturity cultivars, such as Faraman and Goldasht cultivars is recommended.

One of the main challenges of modern agriculture in ensuring food security is development of strategies to deal with potential negative impacts and adapt to climate change. To address this challenge, it is crucial to investigate the effects of climatic factors on agricultural production at a spatiotemporal dimension, develop and utilize crop management decision-support tools, and support targeted agronomic research and policy. These endeavors necessitate the availability of accurate and standardized meteorological data.Studying growth degree days and wheat phenology can significantly enhance our understanding of how wheat growth responds to climate change and aid farmers in adapting to and effectively mitigating its influence.

To determine the environmental and management factors affecting the yield of irrigated and rainfed wheat in different regions of North Khorasan province, we investigated the trend of yield changes from 1980 to 2009. Subsequently, we simulated the wheat plant growth stages using the DSSAT model and analyzed the impact of temperature and rainfall changes on yield through panel data analysis. Panel data analysis is a widely used statistical method in social science, epidemiology, and econometrics for analyzing two-dimensional (typically cross-sectional and longitudinal) panel data. This method involves collecting data over time from the same individuals and conducting regression analysis across these two dimensions.

According to the results of this study, 63% of the changes in irrigated wheat yield between the years 1980-2009 can be attributed to environmental factors (temperature and precipitation), while 37% can be attributed to management factors. When comparing environmental parameters, it was observed that the number of temperatures above 30°C (N30TMAX), mean temperature (GSTMEAN), interaction of amount and frequency of precipitation (TPRAT * NPRAT) significantly affect yield (p ≤ 0.05). Bojnord, Shirvan, and Esfarayen regions exhibited significant positive cross-sectional effects in terms of environmental parameters, whereas Farooj, Raz-Jargalan, Maneh Semelghan, and Jajarm regions displayed negative cross-sectional fixed effects.A study examining the critical stages of wheat growth during good years (with high wheat grain yield) and poor years (with low wheat grain yield) revealed that in all weak years, the minimum temperatures fell below the critical level (-11°C). The occurrence of very low temperatures during the early stages of growth and primary leaf production, which is the plant establishment stage, resulted in reduced photosynthesis levels and subsequently severe yield reduction.In all regions and for 100% of the studied years, irrigated wheat in the grain-filling stage experienced temperatures above 30°C, leading to negative cross-sectional effects in Farooj, Raz-Jargalan, Maneh-Semelghan, and Jajarm. The frequency of temperatures above 30°C during the hard dough stage of irrigated wheat was higher than that during the soft dough stage in all regions. Therefore, delaying the planting date from October (the common planting date in the studied areas) would result in conflicts with high temperatures during the soft dough stage and negative temperatures during the primary leaf production stage and plant establishment at the beginning of the growing season, severely reducing yield.

In general, the results of this study demonstrated that implementing effective management methods, particularly selecting the appropriate planting date, can lead to better adaptation of wheat's phenological stages to environmental conditions. This, in turn, has the potential to enhance wheat yield.

Rice is one of the most important cereals and staple food of many people in the world. In order to identify the possibility of supplying food to the world's population, given the need for continued production in sustainable agriculture, it is necessary to correctly predict the yield of crops. For this purpose, modeling of growth stages and yield of rice based on meteorological statistics of Iran, was studied in Gorgan University of Agricultural Sciences and Natural Resources. The purpose of this study was to use the simple model SSM-iCrop2 to simulate rice growth and yield to investigate the effects of climatic factors, soil, agronomic management and to determine the genetic coefficients of rice in Iran. Due to the appropriate ability of the model in rice simulation, it can be used as a suitable tool for better planning and management of rice fields in the country. In this study, the SSM-iCrop2 model was used to simulate the potential yield. In this model, the amount of potential yield is calculated based on meteorological data, soil conditions, management and plant parameters. The model needs a series of inputs to run, which is made to perform the simulation of the collected model. The most important processes to be simulated in the model are plant phenology, leaf area changes, dry matter production and distribution, and soil water balance. For parameterization and evaluation of the model, the values of performance and day to maturity of the simulated were compared with those observed. For this purpose, a set of experimental data (data related to rice growth and production from published and unpublished articles and reports) was used in important areas under rice cultivation. According to the statistics of the Ministry of Agriculture, 2001-2016, the main areas of rice cultivation and production in Iran were identified. In this study, to compare the deviation of the simulated values from the observed squared error mean (RMSE), coefficient of variation (CV), correlation coefficient (r) and the deviation of the simulated results from line 1:1 with a range of 20% difference. Between the simulated and observed values was used to test the model results. In parameterization of SSM-iCrop2 model for rice, the comparison of observed and simulated days to maturity with RMSE, CV and r values of respectively 12 days, 11 percent and 0.61, respectively, and for grain yield of 56 g m-2, 21 percent and 0.80 indicated the accuracy of the used parameters. Furthermore, in evaluation the model, RMSE, CV and r values for days to maturity were 9 days, 10 percent and 0.95 and for grain yield were 43 g m-2, 14 percent and 0.77 and in simulation evapotranspiration were 44 mm, 9 percent and 0.79 respectively, which confirms the precision of the model simulation. Application of SSM-iCrop2 model is simple and acceptably precise simulation is possible with minimal parameters and inputs. The results of parameterization and evaluation of SSM-iCrop2 model, which was (RMSE), (r) and (CV), showed that this model includes phenological stages and grain yield in the history of different plantings in the climatic conditions of Iran simulates with great accuracy, which indicates the appropriate structure of the model in the simulation. Therefore, considering the appropriate accuracy of SSM-iCrop2 model in simulating rice phenology and yield, it can be used as a suitable tool to study cropping systems and interpret the results in different environmental and management conditions to plan and improve the management of rice fields in the country.

Temperature during flowering and seed filling is a very important indicator for estimating the yield potential of rapeseed. In order to evaluate the effect of heat stress due to delay in sowing date on agronomic characteristics of different rapeseed genotypes (including, Hyola420, Hyola50, Hyola60, SAN37, SAN34 and Dalgan) two separate experiments on two Conventional sowing date (11th Nov.) and late sowing date (16th Dec.) each in the form of a randomized complete block design with three replications was carried out in the research farm of Islamic Azad University, Ramhormoz Branch, during the growing season of 2016 and 2017. Each sowing date was considered as an environment and the data were finally analyzed by combined analysis. The results showed that with delay in sowing date and the occurrence of heat stress at flowering and seed filling stages, the number of flowers on the main raceme, ratio of siliques produced per flowers produced, number of siliques per plant, and branches per plant, number of seeds per silique, 1000-seed weight, silique length, plant height and reproductive period decreased and led to significant reduction in seed yield. Reducing silique numbers per plant had the highest contribution to reducing seed yield. In conventional sowing date, seed yield in Hyola 420 and SAN 34 was higher than other genotypes. Under heat stress conditions due to delay in sowing, seed yield in Hyola50 followed by SAN34 was higher than other genotypes and Dalgan had the lowest seed yield. The lowest percentage of reduction seed yield was belonged to Hyola50 (55%) and the amount of stress susceptibility index in this genotype indicated that it was semi-tolerant to late season heat stress. In conventional sowing date, genotypes that quickly reached to the flowering stage but had a longer flowering period, had higher yields. In late sowing date, significant negative correlation was observed between the duration of flowering with number of siliques per plant, number of seeds per silique and seed yield. SAN 34 had high yield in both conventional and late sowing dates and is suggested as a suitable genotype for achieving stable yield in Ramhormoz region.

The increase in global temperature predicted by several climate models has a direct impact on plant growth, yield, and cotton quality. This type of temperature change in agriculture can be produced by planting crops at different dates and growing crops under different temperature and humidity conditions. The objective of this research is to model the evolution of phenology in commercial cotton varieties using meteorological parameters.

To determine the required GDDs of commercial cotton varieties under different planting dates, field experiments were conducted in 2018 in two regions, Hashem-Abad (Gorgan) and Karkandeh (Kordkoy). To estimate the effects of planting date on phenology, field experiments were conducted using a split-plot design with 6 planting dates (15 days apart) as the main plot and 3 cultivars (Golestan, Latif and Sajedi) as subplots with 3 replicates. Data analysis was performed using SAS software and Excel software was used to prepare the graphs.

The results showed that the effect of planting date on days required from planting to boll opening was significant at p = 1% in both Karkandeh and Hashem-Abad. Thus, with a delay in planting date, the number of planting days to emergence increased from 7 and 9.1 to 4.6 and 3.1 days in both Karkandeh and Hashemabad, respectively; to the budding stage from 52 and 46 to 29.2 and 23.2 days, respectively; to flowering from 63.3 and 57.9 to 41.9 and 33.3 days, respectively; to flowering from 75 and 63.8 to 58.The results of yield comparison showed that the highest yield of total cotton (4015 kg ha-1) was associated with the second planting date among the employees and in Hashemabad the highest yield of total cotton (4122 kg ha-1) was obtained with the third planting date.

The results of this study showed that the GDD required for cotton cultivation was significantly different among the different planting dates.

Prediction of development periods of crops by mathematical models, especially, time to growth ending is so important in every area. So, as impotence of prediction of phenology, leaf area and time to leaf growth ending, this research performed to introduce and test of Phenology MMS model in environmental conditions of Boukan, prediction of leaf appearance rate, phyllochron in stress condition of drought and to correct coefficient of allometric equations of predicting of leaf area of Corn (cv. Single cross 704) and Sunflower (cv. Shamshiri).

In this research, Phenology MMS evaluated using field data for corn and sunflower . Then time and thermal time needed to leaf growth ending and phyllochron (degree day per leaf) obtained using segmented model in every stress level. So, the best algometric model selected for describing of relation between leaf area and leaf number.ResultsResults showed that the model predicted development periods of corn and sunfloer well and was capable to estimate day and thermal time needed to every special development period in two state: day after sowing and day after emergence. Also, in corn, results released that time to leaf growth ending will occur after reception of 782.9 degree day which equal to 72.3 day after emergence whereas for sunflower time to leaf growth ending will occur after reception of 798.1 degree day which equal to 59.14 day after emergence. On other hands, a leaf will include to plant 3 and 2.06 day after emergence in corn and sunflower respectively. In medium tension, the slope of regression line of leaf number versus thermal time, increased and reached to 0.0285 and 0.033 leaf per degree day in corn and sunflower respectively. Results of predicting of leaf area using exponential segmented models showed that all of models were good in predicting of leaf area index.

As for being acceptable of results of phonological model for prediction of thermal time, leaf number and phyllochron, we advise using of this model in modeling and agronomical studies. So, drought stress can effect on leaf appearance rate and phyllochron value. All of models were good in predicting of leaf area index.ConclusionAs for being acceptable of results of phonological model for prediction of thermal time, leaf number and phyllochron, we advise using of this model in modeling and agronomical studies. So, drought stress can effect on leaf appearance rate and phyllochron value. All of models were good in predicting of leaf area index.

Common bean (Phaseolus vulgaris L.) with 20-25% protein and 50-56% carbohydrate content, has a crucial role in supplying the required proteins and maintenance of food security of the community. Among the Asian countries, China, Iran, Japan and Turkey are the major producers of common bean. According to the figures provided by the Ministry of Agriculture, cultivation area and production of bean in Iran in 2016 were 114593 ha and 222705 tones, respectively. In recent years, due to the increase in the population and in order to rapidly meet the demand for more food as well as decision making at micro and macro-levels, simulation of crop growth and yield using the models has gained attention due to rapid preparation of the results, lowering the execution costs and the possibility of simulation under various climatic and management conditions. In order to model the growth stages and yield of bean using the figures of Iranian meteorology organization (minimum and maximum temperatures, radiation and rainfall), a study was conducted at Gorgan University of Agricultural Sciences and Natural Resources. The simple SSM_iCrop2 model was used for this study. This model has been tested and proved for a wide range of plant species. This model requires easily available and limited input information. The aim of this study was to parameterize and evaluate the SSM_iCrop2 model for simulation of growth and yield of common bean in order to investigate the effect of climatic, soil and crop management factors as well as determination of genetic coefficients under Iran conditions using the sub-models associated with phenology, dry matter production and distribution and the changes in leaf area.
 
SSM_iCrop2 model was used as the base of this study. Observed and simulated yield and days to maturity values were compared for parameterization and evaluation of the model. For this purpose, a series of experimental data (data associated with the growth and production of bean and reports from the published and unpublished papers) in major bean cultivation areas of the country were used. First, parameters related to phenology, leaf area, dry matter production, yield formation and water relations were estimated. Then, the model was evaluated using a series of data which were independent from the experimental data used for parameterization. Crop management inputs were also entered according to the experiment reports. For statistical analysis and investigation of model precision in comparison of the data recorded in the previous studies with the data simulated by the model, correlation coefficient (r), root mean square error (RMSE) and coefficient of variation (CV) were calculated and 1:1 diagram was also drawn.
 
In parameterization of SSM_iCrop2 model for bean, the comparison of observed and simulated days to maturity with RMSE, CV and r values of respectively 14 days, 13 percent and 0.76 and comparison of observed and simulated grain yield with RMSE, CV and r values of 62 g m-2, 20 percent and 0.84 indicated the accuracy of the used parameters. Furthermore, in the evaluation stage, RMSE, CV and r values for days to maturity were 8 days, 8 percent and 0.74 and for grain yield were 53 g m-2, 19 percent and 0.77, respectively, which confirms the precision of the model simulation. The model simulated the evapotranspiration of been in a good manner. The values for RMSE, CV and r for the comparison of the observed and simulated evapotranspiration were 63 mm, 11 percent and 0.85, respectively. Application of SSM_iCrop2 model is simple and acceptably precise simulation is possible with minimal parameters and inputs. This model was able to simulate the growth period and yield of bean cultivars in a good manner despite high variations using thermal unit parameters form sowing to harvest, maximum leaf area and maximum harvest index.
 
Growth and yield of bean was successfully simulated using SSM_iCrop2 model using minimal and available parameters despite different growth habits and high phenotypic and genotypic variations among the cultivars. The results of the model evaluation performed using RMSE, r and CV showed that this model is able to simulate maturity time and grain yield of bean sown in various dates under Iran climatic conditions with a high precision. Thus, due to suitable precision of SSM_iCrop2 model in simulation of bean phenology and yield, it may be used as a suitable tool for investigation of crop systems and interpretation of results under various environmental and management conditions for planning and improving the management of bean fields in the country.

Cotton is the most important fiber crop in Iran and as well as the world. The acreage of cotton is about 80,000 ha in Iran. The present study aims to determine the parameters of the SSM-iCrop2 model and evaluate the ability of the model to simulate cotton growth and yield in different regions and environmental conditions of Iran. Different aspects of crop growth are organized as sub-programs including phenological development, leaf area changes and dry matter production and distribution. Soil water balance sub-program is entered in the model to simulate changes in soil water and determination of stress severity. Simulation by the model is done on a daily basis and requires data related to atmosphere, soil and crop management. The model was tested for Iran conditions. To estimate the coefficients and evaluation of the model, data obtained from experiments conducted in various areas of the country were used. The model was evaluated using independent data following estimation of genetic parameters. The results indicated acceptable efficiency of the model in prediction of daily simulation including days to maturity (RMSE=8.4 day, CV=6.5 %) and seed cotton yield (RMSE=56.6 g/m2 and CV=13.9 %) for parameterization and seed cotton yield (RMSE=50.4 g/m2, CV=12.8 %) for evaluation. Also, the results showed that RMSE and CV values for simulation of yield, Evapotranspiration, and used water were respectively (77.6, 12.9%), (150.3 and 16%) and (178.5 and 19.6%) in major cotton production areas of Iran. These results indicate that estimates for variables are acceptable.

The present study was conducted to parameterize the SSM_iCrop model and evaluate the prediction of growth and development of faba bean in Gorgan climate condition. This study was carried out on faba bean cv."Barkat" as split-plot in randomized complete block design with four replications at Gorgan University of Agricultural Sciences and Natural Resources in 2015-2016. The experimental factors consisted of planting date (27 November, 25 December and 31 January) and plant density (5, 15, 25 and 35 plants/m2). The parameters of phonological stages, leaf expansion and senescence, production and distribution of dry matter and water balance were estimated using the present data experiment and other data. The results of model evaluation showed that, it can well predict, days to flowering (RMSE = 3.8 and CV =4.1), days to maturity (RMSE = 11.9 and CV= 8.1), node number on main stem (RMSE = 1.7 and CV = 10.0), leaf area index (RMSE =0.8 CV =28.8), biological yield (RMSE = 158.5 and CV =21.6) and seed yield (RMSE = 118.6 and CV = 24.7). Therefore, the SSM_iCrop model can be used to evaluate the agronomic management and analyze the growth and yield of faba bean in Gorgan conditions.

n order to investigate the phenological characteristics of Mastar (Sclorhachis leptoclada Rech.f) in natural habitat and to determine its cardinal germination temperatures, the study was conducted in 2018 in one of its natural habitats in South Khorasan province located in Ark protected area in in Research Laboratory of Islamic Azad University of Birjand. Treatments were seven treatments consisting of temperatures of 2, 5, 10, 15, 20, 25 and 30 °C with four replications in a completely randomized design. Measured traits included germination percentage and rate, average germination time, length and fresh weight of radicle and plumule and dry weight of seedling. Results of ecological study of the habitat showed that the habitat was mountainous and rocky with sandy soil and acidity of 8.18 with an average annual rainfall of 150 to 200 mm. The study of phenological stages of Mastar plant also showed that this plant needs 138 days and 1393.6oC during the growth stages. Regression analysis of seed germination data showed that, minimum, optimal and maximum germination temperatures were determined at 5, 10 and 30 °C, respectively.

The experiment, is based on the standard scenarios, loaders case IPCC (B1, A2, A1B) by general circulation model (HadCM3) with the use of fine scale model (LARS-WG) with the aim to evaluate the effect of climate change on the phonological stages answer C3 plants, in research farm of agricultural college of Lorestan University in cropping years 2014-15 and 2015-16 With, in two consecutive years and rain fed conditions was conducted in one place. Complementary components of intercropping of broad leaf vetch and barley in 5 levels, weeds and compost as well as four levels, respectively. in 4×5 factorial experiment with in a randomized complete block design was used for the target year 2055 AD (1445 Shamsi) in dry land conditions. Climatic factors as temperature, precipitation and daily radiation in period of study with simulation used LARS-WG modeling. Thus, min and max temperature oscillation in the future desirable for growth of C3 plants (broad leaf vetch and barley). Also, average precipitation is slightly more and will reduce the length of the period of growth and failure to deal with the above optimal temperatures and drought stress and escape from the end of the season due to being the period in accordance with growing season, reduce the risk of environmental hazards in the upcoming years due to performance and stability have been achieved fitted.

Wheat (Triticum aestivum L.) is one of the world's largest cultivated plants and one of the most important aspects in wheat breeding is the stability of cultivars under various environmental conditions. The stability of a product is, in fact, its ability to survive in a particular environment. In other words, a plant must be able to tolerate cold, heat, shortage or excess water, changes in the length of the day, the intensity of light, and a wide range of chemical and physical conditions of the soil.
 

In order to study the response of rainfed wheat cultivars in semi-arid and semi-humid regions of Golestan province, an experiment was conducted at the research farm of Gonbad Kavous University (semi-arid area) and a field in Gorgan (semi-humid area) based on the randomized complete block design with four replications and with seven wheat cultivars (Aftab, Azar 2, Sardari, Qaboos, Karim, Koohdasht and Line 17) in 2015-2016. In this experiment, the phenological traits (days from planting to anthesis, physiological maturity), morphological traits (grain filling period, grain filling rate, maximum leaf area index), yield and yield components (number of tillers per square meter, grain per spike, spikelet per spike, grain per square meter, mean grain weight, grain yield, biological yield and harvest index) of cultivars were evaluated in two regions. To compare the means, LSD test was used at the 5% probability level. All analytical steps were performed in SAS software version 9.4.
 

The results of analysis of variance showed that the effect of cultivar in Gonbad and Gorgan regions on all traits except grain filling rate in Gorgan and number of tillers per m2 in Gonbad-Kavous was significant at 1% and 5% levels. The average period of examination in Gonbad-Kavous was 178 days and in Gorgan 195 days after planting. In Gonbad-Kavous, Sardari cultivar (33 days) had the highest and Line 17 (27 days) had the least grain filling period. But in Gorgan, the Qaboos cultivar (41 days) was the highest and the Koohdasht cultivar (38 days) had the least grain filling period. The results also showed that there was a significant difference between the cultivars in both locations in terms of grain filling rate. In Gonbad-Kavous, Azar 2 had the lowest grain filling rate (5.8 g.day.m-2), and Line 17 had the highest grain filling rate (14.2 g.day.m-2). But in Gorgan, Sardari cultivar had the lowest (5.5 g.day.m-2) and Koohdasht cultivar had the highest (14.37 g.day.m-2) grain filling rate. Correlation coefficient between grain filling period and grain yield (r= 0.359**) and grain yield and grain filling rate (r= 0.847**) were positive and significant. Grain yield and harvest index were higher in Gorgan than Gonbad-Kavous. In Gonbad-Kavous, there was no significant difference between grain yield per unit area, biological yield per unit area and harvest index in most of the cultivars. In Gorgan, there was a significant difference between cultivars for grain yield, but there was no significant difference between biological yield and harvest index among more cultivars. In Gorgan, Koohdasht and Sardari cultivars had the highest and lowest grain yield per unit area (564.2 and 218.3 g.m-2) and harvest index (50.32 and 32.2%) respectively. There was a significant correlation between grain yield and harvest index (r= 0.907**) and biological yield (r= 0.665**) in the level of 1%.

In general, due to the fact that other than cultivars Sardari and Azar 2, which are special for cold regions, other cultivars are compatible with tropical and semi-arid conditions. According to the climatic conditions (rainfall and temperature), two regions of Gorgan and Gonbad-Kavous were observed during the experimental period which were more in line with the tropical conditions. In most traits, there was a slight difference between the cultivars. Different cultivars achieved high grain yield in Gonbad and Gorgan. In Gorgan region, Koohdasht cultivar had a shorter time from planting to maturity and this cultivar had higher grain yield. In Gonbad Kavoos region, although the Qaboos cultivar had no superiority in most traits than other cultivars, it had the highest yield and shorter time from planting to maturity and harvest.