جستجوی مقالات مرتبط با کلیدواژه « تاریخ کاشت » در نشریات گروه « زراعت »

The present study was conducted in order to estimate the yield gap of faba bean in the main production areas of this plant in Golestan province, including Gorgan, Ali Abadkatol and Aq Qola cities, and to identify the factors that cause it and to determine the contribution of each of them.

Based on this, the information related to the production management of 445 faba bean farms in Gorgan, Aliabadkatol and Aqqola regions in 1398-1399 and 1399-1400 was collected and the yield gap was estimated using the comparative performance analysis (CPA) method.

 The average, maximum, and gap yield of faba bean seeds were 2742, 4000, and 1258 kg per hectare, respectively. Additionally, based on the results obtained, the most important reasons for the yield gap and the contribution of each of them in creating the yield gap were: planting date 21%, pests 15 percent, the amount of pure nitrogen (N) 14 percent, the number of disc times 14 percent, the amount of seed used 12 percent, diseases 12 percent, waterlogging 5 percent, weeds 3 percent, non-use of working row 2 percent and improper planting depth 1 percent.

In general, by optimizing the management of faba bean production and eliminating the mentioned factors of yield gap, it is possible to increase the yield of faba bean in the regions of Gorgan, Ali Abadkatol and Aq Qala of Golestan province by 46 percent (equal to 1258 kg per hectare) compared to the current amount increased.

This study aimed to investigate the response of four ecotypes of milk thistle from Isfahan, Kohgiluyeh va Boyer Ahmad, Khuzestan-Omidiyeh, and Hungary to three irrigation regimes (irrigation after 40%, 60%, and 80% maximum allowable depletion of available soil water (evaluated in 2020-2021 under five different planting dates (September 27th, October 17th, November 6th, November 26th, and March 10th) at the research farm of Isfahan University of Technology in Iran. The experiment was conducted as a combined analysis of a split-plot based on randomized complete block design with three replications. The results showed that the highest and the lowest grain yield and shoot dry weight of milk thistle plants were obtained under the October 17th and March 10th planting dates, respectively. Water deficit at both levels decreased grain yield, shoot dry weight, number of flowers per plant, plant height, flowering degree-days, and physiological maturity degree-days, but increased grain and shoot water use efficiencies. The "Kohgiluyeh and Boyer Ahmad" ecotype exhibited the highest seed yield, shoot dry weight, seed/shoot water use efficiency, and harvest index, making it a promising candidate for breeding programs aimed at creating adaptive cultivars of the milk thistle plant. Based on the study's findings, it can be concluded that milk thistle should be planted in the fall season from late September to mid-November under similar climate conditions.

The effect of the combined use of nitrogen fertilizer with sugarcane residue compost and growth-promoting bacteria on wheat quality traits and yield in the heat stress conditions of the end of the season in Ahvaz was investigated.

An experiment was carried out in the form of two split plots in the form of a randomized complete block design with three replications. The experimental factors include three sowing dates: 22 November, 11 December and 31 December in main plots; six combined of nitrogen with compost include control, 100% nitrogen, 75% nitrogen+ 25% compost, 50% nitrogen+ 50% compost, 25% nitrogen+ 75% compost and 100% compost in sub-plots and two levels of use and non-use of bacteria in sub plots.

Results showed the effect of Sowing date and the combined use of nitrogen with compost and growth-promoting bacteria were significant on all measured traits. Average comparison showed that combined use of 50% nitrogen + 50% compost with bacterial application increased the characteristics of Grain filling duration and Grain filling rate, Grain protein percentage and wet gluten. Also, the highest seed yield (5864 kg/ha) was obtained on the first planting date and combined consumption of 50% nitrogen + 50% compost and the lowest amount (1115 kg/ha) was obtained on the third planting date and the control treatment.

The combined use of nitrogen fertilizer and compost with growth-promoting bacteria could reduce the negative effect of heat stress at the end of the season on the measured plant traits.

Study of the promising plant Niger seed with the goal of oil production in Pakdasht

This research was carried out in the form of a split-split plot in the form of a randomized complete block design with three replications in the year 2021 in the Aburihan campus research farm located in Pakdasht. In this study, irrigation cycle in three levels (once every 7 days, once every 10 days and once every 13 days) as the main factor, planting date in two levels (5 June and 22 June) as a secondary factor and fertilizing with bio-fertilizers In four-level including control (without biofertilizer), Shift biofertilizer, Chris biofertilizer and the combination of Shift and Chris biofertilizers as sub-factors were considered.

The results showed that the plants cultivated on June 22 were superior to the plants cultivated on June 5 in all investigated traits (including yield components, seed yield, and biological yield) and all three tested irrigation levels. Also with increasing levels of drought stress, the seed yield has significantly decreased in both planting dates under investigation. However, the ratio of seed yield reduction under drought stress was significantly lower in plants cultivated on June 22nd compared to those cultivated on June 5th.

The cultivation of seed Niger plant with the application of Chris biofertilizer in the same weather conditions on June 22nd, is recommended as a promising plant that has an acceptable yield from an agricultural point of view and its product has a high oil content.

Agriculture is a cornerstone of many developing economies, providing food, income, and employment for millions of people. It is also projected to play a vital role in feeding a global population of 9.1 billion people by 2050. However, there are growing concerns about the environmental impact of agriculture, particularly in arid and semi-arid regions like Iran. Managing water and fertilizer usage in agriculture is crucial to ensuring food security and sustainability. However, conducting field experiments to assess the interaction of all factors involved is expensive and time-consuming. This research focuses on optimizing maize production in Kerman province, a region where maize is a major crop. The research is motivated by the need to improve resource management in Iran, where water and fertilizer resources are limited. The APSIM model is used to determine the best management scenario for maize production in Kerman province. APSIM is a crop growth simulation model that can be used to predict the impact of different management practices on crop yield, water use efficiency, and nutrient use efficiency. The use of APSIM in this research provides a cost-effective and time-efficient alternative to conducting extensive field experiments. The results of this research will contribute to the development of sustainable and efficient agricultural practices in Kerman province and similar regions. These regions are characterized by resource constraints, such as limited water and fertilizer availability. The research aimed to simulate the effect of management parameters (planting date and irrigation) on Crop yield and subsequently achieve the optimal management scenario.

The APSIM model was used for simulation in three regions of Bardsir (temperate to cold climate), Jiroft (hot and humid climate), and Orzuye (hot and dry climate). The model requires four series of data: climate, soil, management, and crop data. The required climate data (from 1998 to 2018) including daily maximum and minimum temperatures, length of sunny hours, and daily precipitation were collected and prepared from the synoptic weather stations of the three mentioned regions.The management data set for each of the study regions was prepared in the form of questionnaires and field research from experts of the Agricultural Jihad Organization, the Agricultural Research Center Organization, and prominent farmers in those regions. The crop data includes the plant genetic coefficients of the maize single cross hybrid 704, which were obtained from the calibration of the APSIM model. To optimize planting date and irrigation management in the studied areas, different planting and irrigation date treatments were investigated. In this research, planting date treatments included the conventional planting date of the region, 20 days before the conventional planting date (as early planting date), and 20 days after the conventional planting date (as late planting date). Irrigation treatments included the usual number of irrigations in the region (13 irrigations), less irrigation (11 irrigations), and more irrigation (15 irrigations).

Our results showed that the model successfully simulated maize phenology, especially maturity date, with high accuracy for all fertilizer amounts tested. The model performance in predicting biomass under different nitrogen treatments was also satisfactory, with a minimal difference between observed data and model results. The nRMSE of grain yield in the calibration stage was 11.2% and in the validation stage was 9%. The nRMSE for calibration of the biological yield of SC 704 was 14.8% and for validation was 13.9%. Also, the model was able to simulate phenology with very high accuracy (especially the days to maturity). Overall, the nRMSE of days to flowering was less than 10% and for the days to maturity was less than 5%. Late planting dates consistently showed better performance across regions and irrigation treatments, resulting in significantly increased grain yield compared to conventional and early planting dates. The highest seed yield was obtained with 15 times of irrigation, among the various irrigation treatments. Late planting combined with 15 times of irrigation yielded the best results in Kerman province, particularly in Bardsir, with a yield of 9300 kg ha-1. Optimal moisture and air conditions, along with the cultivation of a late-maturing variety, contributed to the higher seed yield. These findings are consistent with previous research that has confirmed the positive impact of late planting and extended ripening periods on maize yield.

Our results showed that the model simulates the growth and yield of single cross 704 corn in Kerman province well, even after 20 days of late planting. Long-term simulation experiments showed that maize grain yield varied depending on the region, with the highest yield in Bardsir (8317 kg ha-1) and the lowest yield in Jiroft (4735 kg ha-1). The optimum maize grain yield (8872.8 kg ha-1) was obtained by the interaction effect of late planting date and 15 times of irrigation.

Despite of introducing of suitable chickpea cultivars for autumn planting in cold drylands of the country, still planting of chickpeas is dominantly done during the spring. There is a short window for crop growth in dry and semi dry lands which cover majority of the country. Climate change has made this shorter and probability of marginal drought stress has been increased dramatically. In the other hand, presence of weeds during different plant growth stage increase competition for soil humidity and causes a decrease in yield. Short growth period and lack of appropriate management could lead to uneconomic chickpea production. Therefore, different planting dates and weed control were investigated in order to achieve the highest yield of chickpea Jam cultivar.

This research was conducted as a complete randomized blocks design with four replications under Naghadeh dryland conditions. Planting dates included three levels (autumn, dormant and spring seeding) which were assumed as fixed factor and weed control included two levels (mechanical control of weeds and no-control) were implemented. Experimental plots included 6 rows 3 meters length spacing 25 cm from each other. The planting time was October 6 (autumn), December 19 (dormant seeding) and March 24 (spring seeding). 20 (kg/ha) nitrogen from urea and 40 (kg/ha) phosphorous from superphosphate sources were applied as starter in the autumn based on soil analysis results. Some agronomic characteristics were noted along growth and harvesting times and combined statistical analysis were completed using SPSS software.

The highest grain yield and water productivity index were related to the mutual effects of dormant planting date in weed control, with an average yield of 1334 kg/ha and 3.64, respectively. Also, the highest yield energy of chickpea seeds was related to the mutual effects of dormant planting date treatments in weed control with an average of 2721 kcal/ha. The results showed that dormant planting of Jam cultivar has relative superiority over spring and autumn plantings regarding the measured indicators.

Chickpea is one of the important legumes in West Asia and North Africa. It is also one of the important legumes in rainfed agricultural systems in these regions. Although Iran has the fifth rank in terms of under chickpea cultivation, it ranks 47th in terms of average grain yield per hectare (400 kg/ha). In dry areas of Iran, chickpea yield is highly dependent on the amount of rainfall and its seasonal distribution. Therefore, annual changes in rainfall make it difficult to employ a unitary agricultural management that leads to maximum crop yield with a predictable trend over the years. Chickpea is the most important legume crop in Iran, accounting for over 50% of cultivated legume lands, and is primarily planted under rainfed conditions. Chickpea production is significantly lower than other crops.

Simulation of the potential yield of rainfed chickpea was carried out  using the SSM-Chickpea model and rainfed chickpea yield resulting from farmers' crop management practices, including planting date, plant density, and nitrogen in 12 main chickpea growing regions were evaluated. These experiments consisted of 9 independent field experiments. In the current research, the model was evaluated based on the comparison of measured and simulated values for grain yield. Statistical indices including determination coefficients (R2) and normalized root mean square error (nRMS) were used.

The simulation with model SSM-Chickpea showed that the average potential rainfed chickpea yield was 1200 kg/ha. The simulation results also indicated that the optimal planting date for all regions was mid-December, as dormant seeding management, led to an increase in grain yield of about 10% in Urmia and 60% in Khorramabad compared with the spring sowing date. Optimal plant density was 20 plants/m2 resulted in a 27% increase in grain yield in Islamabad-e Gharb. Regarding the plant nutrition, the results showed that using 20 kg/ha as a starter fertilizer led to up to a 10% increase in grain yield in the Eqlid and Khorramabad. In all studied regions cv. Bivanij had 23% greater grain yield comparing ILC 482 and a large part of chickpea grain yield potential depented on agricultural management practices in general and planting date, specifically.

Global warming directly affects agricultural production and food security (Ainsworth & Ort, 2010). Temperature controls the rate of plant metabolic processes that ultimately affect biomass production and grain yield (Hay & Walker, 1981). Although farmers are not able to control the climatic conditions, management and changes in factors such as irrigation, soil, crop varieties, activities, and technologies used in the cultivation of crops can reduce the harmful effects of climate change (Moradi et al., 2014). One of the reliable approaches to studying the effects of climate change on agricultural production is using crop growth models. The present study was conducted to simulate the effects of climate change on phonological stages and yield of maize and to investigate the possibility of mitigating the negative effects of climate change on maize by changing the sowing date and selecting suitable cultivars as management strategies for adaptation to climate change in Kermanshah region.

Materials and Methods :

The study was conducted in Kermanshah region conditions. The evaluated traits included days from the sowing date to anthesis, days from the sowing date to physiological maturity, total dry weight, and grain yield. In general, the results of the evaluations showed that the CERES-Maize model can accurately predict the growth and yield of maize cultivars (SC704, Simon, BC678) in different soil moisture conditions. After ensuring acceptable agreement between simulated values with observed values, the evaluated model was used to study the effects of climate change on maize production in the near future (2021-2050) and the far future (2051-2080) climate change according to RCP4.5 and RCP8.5 scenarios and comparing them with baseline conditions (1981–2010). The average of 17 general circulation models was used to simulate meteorological parameters under climate change conditions. The common sowing date for maize in the Kermanshah region is May 5. In this study sowing dates of May 5 and April 26 as early sowing dates, April 15 as the common sowing dates, and May 25 and June 4 as the late sowing dates, and maize cultivars SC704, BC678, and Simon were considered as adaptation strategies to climate change.

The results of simulation showed that regardless of cultivar and sowing date, traits of days from sowing date to anthesis, days from sowing date to physiological maturity, total dry weight and grain yield in the near future climate change in the scenario RCP4.5 varied as -2, -1.5, 2.7, and 3.3% and in the RCP8.5 scenario varied as, -2.9, -2.8, -0.66, and -3.6% compared to baseline conditions, respectively. These values for the RCP4.5 scenario in the far future climate change condition were -5.2, -5.4, -7.1, and -16.2 and for the RCP8.5 scenario were -8.8, -9.8, -23.1, and -45.83%, respectively. In both near and far future climate changes and under both scenarios, by sowing the studied cultivars at late dates (May 15 and May 25) compared to the early dates (April 15 and April 25) and common date (May 5), the length of the developmental period was shorter but other traits such as total dry weight and grain yield were higher. Among the studied cultivars, in both future climate changes and scenarios, the Simon cultivar had the highest grain yield. The highest duration of developmental stages and total dry weight belonged to SC704.

In general, if any of the RCP4.5 and RCP8.5 scenarios occur in the near and far future climate change periods, the sowing of the Simon cultivar should be in late dates on May 25 and will have the highest grain yield. Therefore, it can suggest as a suitable strategy to reduce the negative effects of climate change on maize production in the Kermanshah region.

The storage conditions of saffron mother corms during the summer dormancy period, including natural and pseudo-dormancy stages, can probably affect the vegetative growth and the production of replacement corms (RC), which has not received enough attention in previous scientific studies. This experiment was carried out as a complete randomized block design with seven treatments and three replicates during the 2019 growing season in Qaen, Iran. Experimental treatments were three types of corm storage inside the soil [corm planting on 5th June (A) with natural soil temperature as control, A + summer irrigation on 5th August, and A + mulch application obtained from wheat residues at the rate of 8 ton.ha-1)] and four types of corm storage outside the soil [corm storage at room (ambient temperature) for three months started from 5th June + corm planting on 5th September (B), corm storage in constant temperature (25 oC and relative humidity of ~40 %) in incubator for three months + B, three months corm storage at variable temperature in incubator (one month in 20, 25 and 20 oC) + B and corm storage in room temperature (up to 5th August) and incubator (up to 5th September) + B. The studied traits were the length, number, and weight of leaves, the number and weight of the total RC, the weight of the main RC, the average weight of RCs, and the number and yield of RCs in different weight groups. The results showed that mulch application caused the highest length and number of leaves (35 cm and 9 No per plant, respectively). Incubation of corms at variable temperatures led to a significant increase in the total weight of RC. In contrast,  incubation at constant temperature had most significant effect on the number of RC (2022 corms per m2). The highest and the lowest mean weights of RC were obtained in the mulch application (7.23 g) and incubation at constant temperature (2.22 g), respectively. Plant residue treatment (mulch) decreased the number of small RC (less than 6 g) and increased the number of RC in the weight groups of 9-12 and 12-15 g. Incubation of mother corms at variable temperatures led to an increase in the number and yield of RC weighing more than 15 g. Overall, the treatments of plant residue consumption and storage of mother corms at incubator with variable temperatures, in which 66% and 61% of the RC yield was in groups weighing more than 9 g, respectively, were the best experimental treatments in terms of improving the growth of RC.

In order to improve soil fertility, increase the capacity to hold water and nutrients in the soil, as well as improve the growth and yield of plants, the use of different organic fertilizers in the soil has great importance due to the problem of lack of organic matter in most soils of Iran. However, organic fertilizers alone are not able to meet the needs of plants and are not sufficiently available to farmers. On the other hand, the high consumption of chemical fertilizers causes environmental pollution and increases production costs. Therefore, in order to efficiently and effectively use organic and chemical fertilizers and achieve sustainable agriculture, combined use of organic and chemical fertilizers is recommended. Considering the effect of heat stress at the end of the season on the reduction of wheat production in Khuzestan, as well as the effect of reducing the use of chemical fertilizers and increasing the use of organic and biological fertilizers on the health of agricultural ecosystems, this experiment aims to investigate the effect of combined use of nitrogen chemical fertilizer with sugarcane residue compost and the application of growth promoting bacteria (PGPR) in late season heat conditions on the growth and yield of wheat were designed and implemented. This research was carried out in order to investigate the response of Chamran 2 wheat yield and yield components to combined use of nitrogen chemical fertilizer with sugarcane residue compost and growth promoting bacteria under the effect of late season heat stress. The experiment was carried out in the form of split-split plots in the form of a basic design of randomized complete blocks with three replications in the crop year of 2021-2022 in the research farm of Agricultural Sciences and Natural Resources University of Khuzestan. The experimental factors include three planting dates on December 1, December 20 and December 10 in the main plots; Six levels of combined use of nitrogen chemical fertilizer (urea) with organic fertilizer, sugarcane residue compost, including control (without chemical and organic fertilizer), 100% chemical fertilizer, 75% chemical fertilizer+ 25% organic fertilizer, 50% chemical fertilizer+ 50% organic fertilizer, 25% chemical fertilizer+ 75% organic fertilizer and 100% organic fertilizer in sub-plots and two levels of application and non-application of growth promoting bacteria (PGPR) in sub-plots. Each sub-plot was 3 meters long and 2 meters wide (with an area of 6 square meters) and included 10 crop lines at a distance of 20 cm from each other. The distance between the main and sub plots was half a meter and the distance between the blocks was considered to be two meters. After harvest maturity, the plants were harvested and the desired traits were measured. Analysis of variance showed that the effect of sowing date and the combined use of chemical fertilizer with organic fertilizer of sugarcane residue compost were significant on all measured traits. Also, the effect of plant growth promoting rhizobacteria was significant on all the measured traits except harvest index. Mean comparison showed that the highest grain yield (5663 kg/ha) was in the sowing date of 1 December and the use of 50% chemical fertilizer+ 50% organic fertilizer and the lowest grain yield (1155 kg/ha) was in the planting date of 10 December and no use of chemical and organic fertilizers. In general, the delay in planting and the occurrence of heat stress at the end of the season caused a decrease in grain yield, but in different planting dates, the combined use of 50% chemical fertilizer+ 50% organic fertilizer increased wheat grain yield.

Heat stress during grain filling period can lead to the reduction of grain yield of wheat. Therefore, in order to evaluate the probable mitigative effect of nitrogen and zinc application of heat stress on physiological properties, grain yield and protein content of wheat (Chamran cultivar), a split-split plot experiment based on RCBD in four replications was carried out in an experimental field of Khuzestan Agriculture and Natural Resources University, Ahvaz, Iran during autumn of 2018-19 growing season. Experimental factors were three planting date (22 November, 11 December and 31 December) as main plot, four nitrogen levels (0 as a control, 75, 150 and 225 kg ha-1 N from urea 46%) as subplot and zinc levels (0 as a control, 10 and 20 kg ha-1 from zinc sulfate) in subplots. The results showed that the delay in planting significantly (P≤0.01) reduced grain protein, leaf chlorophyll index, cell membrane stability index, grain yield, biological yield, and harvest index. Nitrogen application reduced the effects of heat stress on wheat grain yield so that by consuming 75, 150 and 225 kg N ha-1 in cultivation, wheat grain yield was improved by 43%, 59% and 64% for 11 December cultivation date and 50%, 70% and 55% for 31 December cultivation date, respectively, compared to control fertilizer. Zinc application also reduced the effects of heat stress on wheat grain yield, where at late and very late cultivation dates, with the application of 10 and 20 kg ha-1 zinc, wheat grain yield was improved by 5%, 6%, 35% and 40%, respectively. Consumption of zinc also reduced the effects of heat stress on wheat grain yield by increasing grain weight and caused a 24% increase in grain weight. Wheat harvest index decreased by about 18% due to heat stress. Meanwhile, application of nitrogen and zinc at 150 and 10 kg ha-1, respectively, showed the greatest effect in reducing the adverse effects of terminal heat stress on the agronomical and physiological properties of wheat. In general, in case of delayed cultivation, the use of zinc (at least 10 kg ha-1) and nitrogen (at least 150 kg ha-1) can reduce the harmful effects of terminal heat stress in Ahvaz climate and improve physiological (chlorophyll content and cell membrane stability), agronomic and protein content of bread wheat.

The present study is conducted to separate the effective and influential management factors in the production of clover forage in Iran and to identify its limiting factors. In this study, the data obtained from 68 research projects conducted by the Agricultural Research, Education, and Extension Organization (AREEO) throughout the country during the 2009-2020 years have been analyzed, using the meta-analysis method. The results show that planting date -3.31%, planting method -22.82%, species +40.14%, seeding rate (planting density) +1.53%, drought stress -16.16 %, and phenological stage of forage harvesting -15.42% justify the amount of forage clover variation. Thus, fall planting in the middle of September, basin planting method, choosing the Berseem clover species (Trifolium alexandrinum var. Karaj), the seeding rate of 15-20 kg ha-1 (for forage production), and forage harvesting at the phenological stage of 10-25% flowering, are the most important management and agronomic factors in increasing clover forage production in cold and temperate regions, and not complying with one or a set of these factors will reduce the clover production and will cause yield gap. Overall, the species, planting method, and drought stress are respectively recognized as the most important factors affecting clover forage yield in Iran.

The purpose of this study was to identify the effects of climate change on growth, development and yield of chickpea (Cicer arietinum L.) in Gonbad city in order to adapt and improve yield for future conditions. In this study scenarios of increasing temperature by two, four and six°C, increasing Co2 concentration by two percent and reducing rainfall by two percent alone and combined with each other on December, January and February planting dates for rainy and irrigated conditions. Using SSM-iLegume-Chickpea simulation model were investigated. The results showed that increasing the temperature alone in future climatic conditions will significantly decrease chickpea growth, which leads to premature and non-contact with end-season drought stress and yield increase in dry conditions. However, under irrigated conditions, crop yields decrease due to reduced growth period under water limitation conditions. Increasing Co2 concentration alone due to its effective role in photosynthesis, reduced transpiration and increased water use efficiency increased grain yield in rainfed conditions by 23.9 percent and 12.3 percent under water conditions, but under combined effects scenarios under rainfed conditions, temperature It increases grain production doubly, but under aqueous conditions the temperature increases, counteracting the increase in production due to increased Co2 concentration. Comparison of planting dates also showed that December planting date had higher yield in both dry and irrigated conditions compared to January and February.

Terminal heat stress as one of the major abiotic stresses has an important role in reducing growth and crop production in many areas of the world including central and southern Iran.

To evaluate the effect of terminal heat stress on grain yield and some its related traits in bitter vetch, a field experiment was conducted in a randomized complete block design with three replications on 18 bitter vetch ecotypes from four provinces (East Azerbaijan, West Azerbaijan, Ardabil and Zanjan) in the Research Field of Faculty of Agriculture at Vali-e-Asr University of Rafsanjan, Iran in 2020-2021 cropping seasons. The ecotypes planted in three sowing dates (13 Feb., 28 Feb. and 15 Mar.) and the data were combined and run in a combined analysis of variance. The sowing dates were considered the plant will end with the heat of season. Days to 50% flowering, days to flowering end, days to maturing end, plant height, root length, biomass, grain yield, thousand kernel weight and harvest index were measured.

The results of combined analysis of variance showed there were significant differences among the studied ecotypes for all traits in their reaction to terminal heat stress that were implicated high genetic diversity among ecotypes. According to the results of mean comparison of the evaluated traits, terminal heat stress (induced by delay in differnrt sowing dates) caused significant reduction in all traits except plant height and root length. Aso, the results showed that the interaction of sowing date and ecotypes had significant effects on the most of traits. Cluster analysis based on the measured traits at different sowing dates (13 Feb., 28 Feb. and 15 Mar.), was done and the studied bitter vetch ecotypes were divided into 3 groups in each sowing date.

Regarding to the results, Maragheh and Bayghout ecotypes both from East Azerbaijan in terms of tolerance to terminal heat stress were superior to other ecotypes and recommended for direct planting in Rafsanjan condition or using in breeding programs for terminal heat stress.

In order to investigate the effect of planting date on agronomic and physiolocal characteristics of maize hybrids in different groups in Jiroft region of Kerman province, an experiment as a split plot in the randomized complete block design with three replications in the city of Jiroft in the crop year 2017-2018 was conducted. Experimental factors were included planting date as the main factor at three levels of July 27, August 3 and August 10 and different hybrids as a secondary factor at 10 levels of early, late and medium maturing hybrids (701, 703, 705, 706, 707, 201, 260, 400, 370 and 704 as controls). There was a significant difference between the studied hybrids in terms of agronomic and physiological characteristics. The highest number of rows per ear was obtained in hybrid 706 and the highest number of seeds per row was obtained in hybrid 707. Delaying in planting was associated by of increasing stem diameter and biological yield and decreasing of plant height, ear length, number of rows per ear, seed yield, harvest index, GDD to physiological maturity and spad. By Delaing in planting, seed protein percent and proline accumulation increased. The most seed yield was obtained on July 17 in hybrid 260 (18.24 t.ha-1), August 3 in hybrid 210 (17.46 t.ha-1) and August 10 in hybrids 370 and 201 (17.4 and 17.28 t.ha-1). It seems that the delayed planting date due to exposure to unfavorable temperatures during tillering, pollination and granulation, as well as the reduction of the growing period was decreased yield and yield components.

Rice (Oryza sativa.L) is one of the most important grains in the world, which as one of the major food sources, provides food to more than three billion people in the world. In the near future, there are several challenges to achieve higher yields in rice plants, and one of the most basic of these challenges is increasing the average temperature of the earth's surface. Increasing the temperature indirectly reduces production by increasing water demand in areas with limited water and reducing the area under cultivation. Therefore, plant physiologists' understanding of plant physiological responses to high temperatures, as well as the selection of adaptation strategies, is an effective and very important role in rice research. In line with international research, research on introducing a diverse range of heat-tolerant rice cultivars on the one hand and finding effective physiological traits and mechanisms in tolerance or resistance of common rice cultivars in the province to this stress can play a valuable role in inactivation, modulation of negative effects or greater efficiency of the heat and light stress situation arising in the coming years. In other words, making management decisions regarding the production and use of improved cultivars, introducing native tolerant or heat-resistant cultivars and possible required changes in the temporal and spatial patterns of cultivation of cultivars, can be a significant help in combating heat stress. Therefore, this experiment was conducted to evaluate heat stress on grain yield and to study stress tolerance indices in studied cultivars in the Khuzestan region.

In order to evaluate the stress tolerance and susceptibility indices of rice plant (Oryza sativa L.) in response to heat stress, an experiment with two factors of planting date and cultivar on the basis of split plots in a randomized complete blocks design with three replications in two years 2017 and 2018 were carried out in the south of Khuzestan province. In order to apply high temperature stress (heat stress) in field conditions, three planting dates of May 15, June 5 and June 25 were selected as the main plots. At each planting date, seven rice cultivars including Anbouri, Champa, Daniel, Pollen, Hamr, and Hoveyzeh (native cultivars) and N22 (International cultivar) were cultivated as sub-plots. Stress tolerance indices included GWHSI SSI, STI, TOL.

The results showed that at the level of planting date, the highest grain yield was on 5 June with a yield of 5737 kg.ha-1, which was 41.7 more than the first planting date. The highest grain yield was obtained among the cultivars related to Hoveyzeh with an average of 5606 kg.ha-1, which was 34.3% and 29.6% higher than Champa and Anbori, respectively. In evaluating stress tolerance indices, N22 and Hoveyzeh cultivars had the highest SSI and STI, Hammer and Hoveyzeh cultivars showed the highest STI and N22 and Hammer cultivars showed the lowest TOL. The lowest (SSI) was obtained in Hoveyzeh cultivar and then in Hamr and N22 cultivars. The lowest heat stress tolerance was also observed in Champa cultivar. Also, the highest STI index and the lowest TOL index were obtained in Hamr, N22 and Hoveyzeh cultivars. The lowest GDD in all three planting dates was in Hoveyzeh cultivar and the highest one was in sensitive cultivars to heat stress (Anburi and Champa).

In general, heat-tolerant cultivar N22, Daniel and local cultivars Hoveyzeh and Hamr were heat-tolerant cultivar and Geredeh Ramhormoz cultivar and Anbouri and Champa (native cultivars) were identified as heat-sensitive.

According to global warming and climate change, investigating and assessing the efficiency of adaptation strategies are necessary for achieving agricultural sustainable development under future climate conditions. Change in sowing date and dormant seeding for crops can be considered as a suitable strategy to adapt with changing climate conditions. Under dormant seeding management (DSM), the seeds remain ungerminated in the soil, and germinate and emerge with the onset of warming thanks to climate change exploiting late-winter rainfalls, and consequently decreasing frost risk stress at seedling stage and increasing water use efficiency. The main objective of the current study was to investigate the effect of sowing dates especially dormant seeding on rainfed chickpea seed yield in Kermanshah (West) and Tabriz (Northwest) climatic conditions.

In the current study, three general circulation models (MPI-ESM-LR, MPI-ESM-MR and NorESM1) were used under two emission scenarios (RCP4.5 and RCP8.5) for the future of 2039–2069 in Kermanshah and Tabriz regions. GCM outputs were downscale by AgMIP methodology. The SSM-Chickpea model was employed to simulate the growth and development of chickpea (Soltani and Sinclair, 2011). Five sowing dates including 21 December (DSM), 6 March, 21 March, 4 April and 21 April were considered as an adaptation strategy to possible impacts of climate change. Study traits included leaf area index, number of days to maturity, mean temperature over the growing season, cumulative rainfall, evapotranspiration, biological yield, and grain yield.

The results of model validation showed that the model was able to predict the grain yield reasonably well (R2=0.92 and RMSE=14%). Overall, averaged grain yield at all sowing dates in Tabriz was 131% more than Kermanshah in the baseline. High grain yield in Tabriz compared with Kermanshah can be attributed to more leaf area index and length of growing season. Averaged grain yield in dormant seeding was 13.51, 22.30, 31.94 and 46.86% higher compared to 6 March, 21 March, 4 April and 21 April, respectively in both locations at the baseline. On average (GCMs, emission scenarios and locations), dormant seeding had the highest grain yield (24.93%) than other sowing dates in future climate change conditions compared to baseline. The reasons of superiority of dormant seeding of chickpea compared to other sowing dates was due to coinciding of crop growth period with rainfall (Hajjarpoor et al., 2016), reduction in negative effects of high temperatures on grain yield especially during grain filling (Hajarpour et al., 2013), increasing transpiration efficiency due to lower temperatures over the growing season (Soltani et al., 2006) and escaping terminal drought stress at end of growing season. Averaged grain yield (locations, sowing dates and GCMs) under RCP4.5 and RCP8.5 scenarios increased by 8.97 and 14.12% compared to baseline. Increasing grain yield was due to the positive effects of boosting the carbon dioxide concentration on the photosynthesis rate of chickpea as a C3 plant under changing climate (Meghdadi et al., 2014).

This descriptive research was conducted as interviews using 125 questionnaires among the saffron farmers of Torbat-Heydariyeh, Iran, during 2020-2021. The aim of this study was to compare the most important agronomic operations related to saffron cultivation among three groups of farmers (ordinary, skilled and leading farmers), and to compare the methods used by the farmers with the recommendations of saffron researchers. The classification of farmers into the three mentioned groups was based on the stigma yield in relation to the field age. Before the research, the validity of the questionnaire was confirmed and its reliability was also determined using the test-retest method. The results showed that against 15% of leading farmers, none of the ordinary and skilled farmers had agricultural education. The average education of ordinary, skilled and leading farmers were 7.1, 7.5 and 10.9 years, respectively. Corm planting date of the highest number of ordinary and skilled farmers (46.2% and 35.7%, respectively) was in September, while for the leading farmers (37.5%) was in June. The average amounts of corm application by ordinary, skilled and leading farmers was 8.9, 8.9 and 10.5 ton ha-1, respectively, and the average amount recommended by researchers was 10.4 ton ha-1. All the saffron researchers recommended the corm row planting method, which is accordance with the 30, 43.1 and 44.4% procedures of ordinary, skilled and leading farmers, respectively. The minimum corm weight recommended by researchers was 8 g, which is applied by 18.7% of ordinary farmers, 25% of skilled farmers and 100% of leading farmers. Hand weeding was the most common method of weeds control among all farmers. Contrary to the recommendation of most researchers to remain saffron leaves as mulch, the leaves are mainly used as animal feed. The appropriate field age according to researcher’s recommendation was 5-6 years, while most of the farmers use the field for 7-8 years after each planting time. In general, the low level of knowledge, mass planting method (several corms in each planting point), planting of small mother corms, inappropriate planting date and long-term exploitation of the fields were the most important cases of improper field management, especially by ordinary farmers.

Climate change is rapidly degrading the conditions of crop production. For instance, increasing salinization and aridity is forecasted to increase in most parts of the world. As a consequence, new stress-tolerant species and genotypes must be identified and used for future agriculture. Stress-tolerant species exist but are actually underutilized and neglected. Quinoa, scientifically known as Chenopodium quinoa Willd. is a member of the Amaranthaceae family. Promoting the cultivation and nutrition of quinoa will diversify food products in the country, sustainable production, increase farmers' incomes and provide part of the community's food needs. Crop simulation models have been used for various studies such as selecting the appropriate cultivar, determining the best planting date, predicting the effect of diversity and climate change on growth. Field research requires a lot of time and money, while computer simulation models can save time and money by conducting extensive experimental simulations.

This research was conducted in two regions of Yazd province with 10 separate experiments in the form of a randomized complete block design with 3 replications. Experimental factors included 5 promising modified lines in Yazd Salinity Research Center with Titicaca cultivar. The lines consisted of four intermediate maturity lines, numbered 1 (NSRCQE), 2 (NSRCQC), 3 (NSRCQD), and 6 (NSRCQA), one late maturity line numbered 4 (NSRCQB), and the early maturity cultivar Titicaca numbered 5. Sampling and note-taking were performed regularly, once every three days, in proportion to the progress of the phenological stages of each line. A model based on degree-day-growth was prepared in FST language. In preparing the length table, due to the short day of Quinoa, for all lines in the model up to 12.5 hours, the development rate was one, and after 13.8 hours, the development rate was zero. The base temperature in the model was 2 °C. Then, the model was calibrated and evaluated with data taken from the field.

RMSE (CV) coefficient of variation between 7 to 12%, root mean square error (RMSE) between 4.4 to 6.4 days, Wilmot agreement index (d) between 0.99 to 1, model efficiency (ME) between 0.96  to 0.98, the mean deviation from the model (MB) was between 0.05 to 0.08 and the coefficient of determination (R2) was between 92 % to 98%. These values indicated a good estimate of the day to flowering of quinoa with the model written in FST language, and the values of day to flowering simulated gained the necessary validity. The coefficient of variation of nRMSE (CV) is between 6.8 to 8.6%, the root mean square error (RMSE) is between 6.2 and 8.7 days, the Wilmot agreement index (d) is between 0.75 and 0.92, The mean deviation from the model (MB) was between 0.05 to 0.08 and the coefficient of determination (R2) was between 92% and 98%. These values indicated a good estimate of the day to physiological maturity with the model written in the FST language, and the day values to the simulated physiological maturity gained the necessary validity. Calibration and evaluation of model efficiency using root mean square error (RMSE), coefficient of variation or nRMSE percentage (CV), Wilmot agreement index (d), model efficiency (ME), and mean model deviation (MB), coefficient of explanation (R2), line test 1: 1 day until germination, flowering and good physiological maturity was estimated.

The results of this study indicated that, the quinoa model prepared for quinoa in terms of degree-day-growth well predicts the developmental stages (emergence, flowering and maturation) of this plant in terms of maturity (early, medium and late) and can be its help determined the appropriate planting date in different areas. This calibrated sub-model can now be used to evaluate different temperature and photoperiod effects for decision making in a wide range of growth environments in quinoa cultivation systems in current and future climatic conditions. Therefore, this sub-model can be used in educational-research and applied work in the field.

Changing planting dates from spring sowing to Entezari sowing could increase the efficiency of rain use in rainfed farming. This study aims to evaluate the feasibility of Entezari cultivation of chickpea cultivars, experiments were carried out in split plots as a randomized complete block design with three replications in two years. Two planting dates including spring and Entezari sowing and seven chickpea cultivars (Local landrace, Hashem, Arman, Azad, Saral, Adel and Sameen) were used in this study. This study was implemented from November 2016 at two cropping seasons in Boroujen region (Chaharmahal and Bakhtiari province). The results showed that planting dates and cultivars were effective on 100-seed weight, number of pods per plant and grain yield. The interaction of planting date and cultivar was also effective on grain yield (p≤0.01). The results showed that the highest grain yield was obtained from Entezari sowing date (716.9 kg ha-1). In the Entezari sowing date, Adel cultivar had the highest grain yield (812.9 kg ha-1). In spring planting date, Arman cultivar had the highest grain yield (471.9 kg ha-1). In general, it seems that the use of Adel and Arman cultivars in Entezari sowing could be increased farmers' economic income by increasing grain yields (71.9%) at the same cost as spring crops.