جستجوی مقالات مرتبط با کلیدواژه « درجه حرارت » در نشریات گروه « زراعت »

This research was conducted for evaluating the tend of dry matter and oil accumulation in fruits of seven olive promising genotypes under climatic conditions of Dallaho olive research station in Sarpol-e Zahab, in Kermanshah province, Iran, in 2018 and 2019 growing seasons. Ten years old trees of seven olive promising genotypes; D1, Dd1, Gw, Ps1, Bn3, Bn6 and Ds3 were planted using randomized complete block design with 3 replications. The results showed that oil accumulation in olive genotype commenced from July and reached to maximal content in November. The oil accumulation was continuous in fruits and gradually increased in all of genotypes. D1 and Bn3 promising genotypes had the highest oil content in dry matter, and the maximum dry matter was observed in Gw and Dd1. The results of this research revealed that olive promising genotypes had different responses in warm climatic conditions, and oil accumulation was influenced by temperature.

Olive tree (Olea europaea L.) is an evergreen and native plant to the Mediterranean regions. The appropriate area for olive cultivation for oil production has moderate winters and long and dry summers. In high temperatures and intensive radiation, olive trees indicate 80% reduction in leaves photosynthesis (Bongi and Long, 1987). In high temperature and water shortage, fruit and oil quality in olive trees decrease (Saadato et al., 2013). The precursor of oil biosynthesis in olive fruits is carbohydrate (Conde et al., 2008). The semi-arid and arid weather during fruit growth and oil accumulation necessitate the selection of tolerant olive cultivars. The dry matter and oil accumulation strongly depend upon climatic condition and olive cultivars, therefore the choice of the most promising tolerant cultivars that perform successful, under stressful conditions, is inevitable to achieve the high quality olive fruit and oil. 

This study was carried out in Dallaho olive research station (34º 30′ 34′′ N, 45º 51′ 53′′ E, and 580m above sea level) in Sarpolezahab in Kermanshah province in Iran in 2018 and 2019 growing seasons. Ten years old tress of seven olive promising cultivars (D1, Dd1, Gw, Ps1, Bn3, Bn6 and Ds3 were evaluated using randomized complete block design with three replications. In two consecutive years, 2018 and 2019, fruit harvesting was carried out in two weeks intervals from July to November. Dry matter was measured following by Anonymous (1997) and oil content was determined following Dag et al. (2011). Combined analysis of variance was performed using SAS software. Duncan’s Multiple Range Test was employed for mean comparison. Figures were depicted using Excel software. 

The highest oil contente in dry matter belonged to D1 and Bn3 promising genotypes. The highest dry matter was observed in Gw and Dd1 promising genotypes. As harvest date delayed, oil content in dry matter increased, and in September until final harvest in November, the highest oil content in dry and fresh matters was obtained. The oil content is sensitive to temperature variation and by increasing temperature from 16 ºC to 32 ºC, oil content decreased (Borges et al., 2017).The reduction of pomological traits in olive in high temperature conditions is due to enhancement of respiration, oxidative disturbance and reduction of photosynthesis efficiency (Neves et al., 2019). Different olive promising genotypes due to expression of heat shock proteins had different levels of tolerance against high temperature (Nissim et al., 2020). During this research, the mean maximum and minimum temperatures were more than 40 ℃ and 30 ℃ in June, July and August, and the high temperature was accompanied by reduction in relative humidity. The results indicated that maximum and minimum temperatures had negative effects on oil content of some olive promising genotypes.

Saffron (Crocus sativus L.) has been used as food and medicine for Iranians for a long time, from the ancient to the modern period, and several factors have influenced its production and consumption in different provinces, especially Razavi Khorasan. In order to investigate the trend of cultivated area, stigma production and yield of saffron and also the effect of climatic parameters such as altitude above sea level, average temperature, and precipitation on the cultivation and production of this plant in different cities of Khorasan Razavi Province, a study was conducted by using data of Agricultural Jihad Organization during 1984 to 2020. Results indicated that the highest production and cultivated area in the province of Razavi Khorasan in the studied period were related to Zaveh, Torbat Heydarieh, and Roshtkhar, respectively. Zaveh and Torbat Heydarieh also had the largest portion of irrigated production in the province, with 13.3 and 9.4 %, respectively. Upon comparing the yield of saffron across different cities to the provincial average, it became evident that Gonabad and Torbat Heydarieh secured the first and second positions, respectively, in this comparison. Conversely, Kalat exhibited the lowest percentage in terms of cultivated area, irrigated production, and yield ratio compared to the provincial average. Further analysis revealed that elevation above sea level is positively correlated with both cultivated area and saffron production. Interestingly, there exists a non-linear inverse relationship between annual rainfall and cultivated area, production, and yield of saffron. Moreover, the study found that higher average temperatures are associated with increased saffron production, although the average yield of saffron tends to decrease. Regarding similarities across different cities in Khorasan-Razavi province, an investigation at a 75% similarity threshold indicated the possibility of classifying the province's various regions into five distinct clusters. The cities of Bakharz, Gonabad, Kashmer, Mahvalat, and Roshtkhar were in the first cluster, and the cities of Bajastan, Khaf, Torbat Jam, Neishabur, Bardaskan, and Taibad were in the second cluster, and each of the cities of Torbat Heydarieh and Zaveh also formed two separate branches. The rest of the cities were placed in a cluster. In general, the increasing trend of saffron cultivation and production in Khorasan-Razavi province indicates a greater desire to cultivate this plant by the farmers, considering the climatic and soil conditions of this province.

In order to evaluate the trend of saffron yield and study the relationship between saffron yield fluctuations and various climatic parameters, research was designed and conducted in Mashhad, Torbat Heydariyeh, Kashmar, Birjand and Qaen during 20 years (1998-2018). According to meteorological data from the last 20 years, the average rainfall decreased by 33% and the average temperature increased by 0.5 °C . On the other hand, the regression results between yield and climatic parameters indicates that the pattern of temperature rise and decreased rainfall in all studied cities was significantly in line with saffron yield declining. In this period, the study's findings also revealed that over the last 20 years, an average of 112.3 hectares of saffron cultivation have been added to the areas under cultivation of saffron and at the same time, saffron yields have dropped by an average of 0.08 kg per hectare. Climatic indicators significantly affected decreased saffron yield in Razavi and South Khorasan. The results also revealed that the average and maximum temperature were the main variables influencing the reduction of saffron yield. For instance in Torbat-e Heydarieh, the variable of average temperature predicted 42 percent of the variability of the yield and in other cities studied, the maximum temperature variable predicted between 24 and 56% of the variability of the yield. Furthermore, the results of the time series analysis of saffron yield revealed that saffron yield will show a decreasing and negative trend by 2025 in all studied cities. Up to 2025, Mashhad and Kashmar with a slope of 0.09 and 0.07 kg/ha, had the highest and lowest decreasing trends, respectively.

Evaluation the effect of heat stress on winter and summer planting systems on quantitative and qualitative yield of potato cultivars in field conditions Abstract Potato is one of the most important crops in the world which currently is cultivated in many climates of the different parts of the world. In order to evaluate the response of different potato varieties to the planting date in Boshrooyeh area, two independent experiments were carried out using split plot desing in randomized complete block dising in February 2015. The first experiment was conducted using three sowing date, including: February 9, February 24, and March 11, 2016, as main plot and three potato vareties, including: Fontane, Picasso and Sante, as subplot. In the second experiment (summer crop), the same cultivars were cultivated at the sowing dates of August 11, August 27, and September 11, 2016. The results showed that, in both winter and summer planting dates, delaying in planting caused to decrease in tuber yield. In the winter crop, the highest yield was obtained from Sante in sowing date of February 9, and in summer crop, the highest yield was obtained from Fontane and Picasso in sowing date of August 11. The dry matter percentage of the tubers also decreased with delay in planting date, both in winter and summer planting dates. Potato is one of the most important crops in the world which currently is cultivated in many climates of the different parts of the world. In order to evaluate the response of different potato varieties to the planting date in Boshrooyeh area, two independent experiments were carried out using split plot desing in randomized complete block dising in February 2015. The first experiment was conducted using three sowing date, including: February 9, February 24, and March 11, 2016, as main plot and three potato vareties, including: Fontane, Picasso and Sante, as subplot. In the second experiment (summer crop), the same cultivars were cultivated at the sowing dates of August 11, August 27, and September 11, 2016. The results showed that, in both winter and summer planting dates, delaying in planting caused to decrease in tuber yield. In the winter crop, the highest yield was obtained from Sante in sowing date of February 9, and in summer crop, the highest yield was obtained from Fontane and Picasso in sowing date of August 11. The dry matter percentage of the tubers also decreased with delay in planting date, both in winter and summer planting dates.

In order to study the effect of drought stress and salt stress and temperature on Germination and Seedling vigour of resistant and susceptible biotypes of wild mustard (Sinapis arvensis L.) to Acetolactate Synthase Inhibitors from three provinces Golestan, Kermanshah and Khoozestan, three experiments were conducted as factorial based on completely randomized design in four replications. Different salt and drought stresses levels were 0, -3, -6, -9 and -12 bar that created by NaCl and PEG respectively. Examined temperatures were 0, 5, 10, 15, 20, 25, 30 and 35°C. In each three experiments second factors was Biotypes of Wild Mustard include three susceptible (Ker-1, Kh3 and G9) and three resistant biotypes (Ker-2, Kh5 and G3). Studied traits were germination percent and rate, seedling length and seedling vigor index. Result showed salt and drought stresses reduced vigor and early growth of all biotypes but this reduction was different in biotypes. Optimum temperature for all biotypes were observed in 15 and 20°C. In almost conditions, different of resistant and susceptible biotypes of Golestan were not significant but in Khuzestan province, vigour of resistant biotype was lower than susceptible biotype but about Kermanshah biotypes, resistant biotype in many conditions had higher vigour than susceptible biotype. Results showed that resistant biotype of Golestan and Kermanshah caused to high vigor, in competition with susceptible biotypes and crop had better and faster germination and have to find other herbicide or nonchemical methods to control these biotypes.

Three separate experiments conducted to survey the response of two populations of common purslane weed collected from Karaj and Ahvaz on germination and early growth. The first experiment was based on 4 levels of flooding, including 1, 2, 4, 8 days plus non-flooding treatment as a control. Second experiment addressed the impact of various acidity levels, such as 4, 5, 6, 7, 8, 9, 10 and finally third experiment considered the influence of high temperatures of 60, 80, 100, 120, 140, 160, 180, 200, 220 centigrade on germination rate, germination percentage, radicle length and plumule length as well as fresh weight of the aforementioned population of common purslane (Karaj and Ahvaz). Analysis of variance revealed that in both weed populations, all germination indices were impressed by flooding periods, acidity levels and high temperatures. Extending the flooding periods resulted in reducing all measured parameters in both weed populations, so growth of common people was completely inhibited less than 8 consecutive days of flooding. Germination rate and percentage improved gradually by increasing the acidity value from 4 up to 7. An adverse relation was observed between the measured parameters and temperature variations in both Karaj and Ahvaz weed population. Germination rate and percentage, radicle and plumule length as well as fresh weight of seedling decreased significantly in response to increasing the oven temperature. Overall, it can be concluded that boosting our knowledge about both ecology and biology aspects of common person can pave the way for introducing new ways in line with expanding long term strategies, improving management systems and predicting the mode of germination and growth of the this important weed.

Saffron is cultivated in most part of Iran، because of low water requirement and well adaptation to diverse environmental condition. In recent years، for many reasons such as low water requirement، saffron cultivation areas has been increased especially in Khorasan Razavi province. Temperature is one of the most important factors in saffron flowering phenomena. The aim of this research was to evaluate the response of saffron to temperature in Khorasan Razavi province counties (Torbat-e-Heydarieh، Gonabad، Nishabour، Sabzevar and Ghoochan). Climatic data (monthly minimum، average، maximum temperatures and diurnal temperature range) and saffron yield data were collected for past 20 years period. The stepwise regression methods were used to remove extra parameters and only keep the most important ones. By using these equations and ArcGIS software zoning، Spline method was find the best for saffron crop zoning. The results of linear regression in Gonabad showed that minimum، maximum and average temperature and also diurnal temperature range in March and April months had the greatest impact on saffron yield. For each of the four indices (the minimum، maximum and average temperature and also diurnal temperature range) the best area for saffron cultivation was the southern part of the province (particularly Gonabad); so by increasing distance from this area to north areas (such as Kashmar، Torbat-e-Heydarieh، Sabzevar، Nishabour، Mashhad and finally Ghoochan) saffron yield reduced by 30 to 50 percent. Therefore، the northern areas of the province had relatively low saffron yield. According to result of this research، saffron yield in Khorasan Razavi province was significantly influenced by temperature parameters. Flowering which basically is the most important stage of plant growth، is directly setting up with temperature.

Wild poinsettia (Euphorbia heterophylla L.) is a summer annual herb, belonging to the Euphorbiaceae family that has recently introduced in Iran and became a troublesome weed in soybean field in Golestan province. Experiments were conducted under laboratory and greenhouse conditions to evaluate the effects of various environmental factors (temperature, light, salinity and drought stress, pH) and planting depth on its germination. The results indicated that seeds germinated at constant temperature range of 15-45 C both in 14 h photoperiod and in darkness. However, germination was greater in the light/dark regime than in darkness, as maximum germination percentage (83%) and germination rate (11.34 seed day-1) was observed at 35 C with the 14 h photoperiod. At alternating day/night temperatures, the highest germination percentage (95%) and germination rate (12.99 seed day-1) occurred at 40/30 C. Germination was reduced with increasing draught stress and no germination was observed at -1.0 MPa. Wild poinsettia seeds germinated >80% at salt concentrations of 0-40 mM. Germination declined with increasing salinity stress. Germination was 13% at salt concentrations of 160 mM. Germination was not affected by pH levels. Maximum emergence was (88-95%) when seeds were sown at 0.2-3 cm depth in soil, with no emergence occurring at a planting depth of 6 cm. It is concluded that several environmental factors affecting the germination of wild poinsettia, and this information could help to predict the spread of wild poinsettia in new areas.

In order to study the effects of salinity stress (made by sodium chloride and calcium chloride) and temperature interaction on germination characteristics of hyssopus officinalis، an experiment was conduct on factorial basis and in a completely randomized design with three replication at laboratory of Khorasan Razavi Agriclultural and Natural Resource Research Center in 2010. In this experiment، different osmotic potentials (0، -3، -6 and -9 bar) and also different temperatures (20، 25، 30 and 35 centigrade degree) were used. In this research، the percentage and rate of germination، the length of radicle and plumule، length ratio of radicle and plumule and seed vigor characteristics has been measured. The results showed a very significant effect of salt levels، osmotic potential and temperature on the above characteristics. The mean comparison for percentage and rate of germination characteristics showed that calcium chloride with 63% and 7. 11 respectively had a significant difference with sodium chloride with 50% and 1.. The highest percent and rate of germination were seen in -3 bar osmotic potential made by calcium chloride in 25 centigrade degree. The highest length of radicle and vigor was in -3 bar osmotic potential made by calcium chloride in 20 centigrade degree. The highest length of plumule was seen in both sodium chloride and calcium chloride in 0 bar (control) osmotic potential and 30 centigrade degree. Generally while the osmotic potential increases and temperature goes up to 30 centigrade degree all the characteristics in sodium chloride and calcium chloride had a remarkable reduction. Also increment of high temperatures had more harmful effects in NaCl than CaCl2. Study the Hyssop plant response to different levels of salinity and temperature on germination stage، it will assist farmers in establishment and desirable production.

To study the effect of different temperatures on germination of susceptible and resistant biotypes of wild mustard (Sinapis arvensis) and to determine their cardinal temperatures and to evaluate their fitness in drought, salinity and pH, four separate experiments were conducted in CRD with 4 replications. The seeds were collected from Aghgala, Aliabad and Gorgan and the experiments were conducted with seeds of F1 generation of each biotype. Temperature treatments were 0, 3, 5, 10, 15, 20, 25, 30 and 35 oc and seeds were kept in dark condition. Germinated seeds were counted twice a day with 12 hours intervals. Base, optimum and maximum temperatures for susceptible and resistant biotypes of Sinapis arvensis estimated as 2.2, 2.3, 23, 25 and 40, 39 oc, respectively. There were significant differences between physiological characteristics associated with drought, salinity and pH of resistant and susceptible biotypes of wild mustard. Increasing the drought stress from -0.4 to -1 MPa decreased the germination of all biotypes. Susceptible biotypes showed high sensitivity to acidic pH and had low germination in these pH.

Data from wheat breeding trials، conducted over the country during 1982-1994، were used to developing models for estimating developmental stages (DS) of two wheat cultivars، Omid and Bezostaya. Developmental rate (DR) for emergence، stem elongation، heading and maturity stages was determined by using the inverse of developmental duration as the dependent variable and various temperature variables and combinations of these variables as the independent variables in a stepwise regression model. A step of the regression was considered appropriate، if the highest R2 was accompanied by the significant (P<0. 1) regression coefficient and partial coefficient of determination. Evaluation of model accuracy and sensitivity was performed using the data of Isfahan and Oromieh. Based on the ratio of absolute value of maximum deviation from the regression line، to actual period of developmental stages، (expressed as the percentages) long developmental stages were estimated well، that indicate efficiency of calculated models، especially for Omid. The results of this study indicate that the contribution of temperature and day length to various stages of development is not the same. Thus، a separate model may be needed for each cultivar and each DS. Dividing the country to homogenous groups، in respect to temperature and day length، may increase the accuracy of estimating models. This requires availability of sufficient phonological information from various climatic zones.

This research were conducted on 2007-8 and 2008-9 cropping years in Agriculture Research Center of Khuzestan in split plot experiment using complete randomized block design with four replications in which main plots were consisted of three planting dates (Nov11, Dec11 and Jan11) and sub plots were included three canola cultivars (Hayola 401 Shirali, and R.G.S). Results showed that planting date delaying caused dry matter reduction in response to growth duration, which reduced plant height and consequently reduced stem and leaf dry matter pod and grain weight. According to two years mean comparison to Nov11 planting date total and leaf dry matter reduced 41.6 and 74.9, and 47.2 and 83.1 percent in Dec11 and Jan11 planting dates respectively. Planting date delaying caused stem and pod dry matter and grain weight reduced 58.1 and 87.5 and 42.1 percent respectively. Vegetative growth duration and flowering period reduced %15.6 and %26.2 and %20.3 and %35.2 respectively in Dec11 and Jan11 planting dates comparison to Nov11 planting date. Heat unit accumulation reduced vegetative growth duration(%21.6 and %29.5), flowering period (%6.1 and %14.6) and ripping (%6.6 and %12.2) in two delayed planting dates in compare to optimum planting date for high yield Potential early growth canola cultivars and November planting date recommended, it must be avoided from delayed planting date.

In this research the effects of cold were evaluated on coleoptile growth of 18 rice genotypes in two separate experiments. The first experiment was carried out as factorial based on randomized complete block design with three replications. In this experiment، two factors were including genotypes at 18 levels and temperature at 5 levels (9، 13، 17، 21 and 25 C°). The seeds of genotypes don’t germinate at 9 C°. The length of coleoptile was measured in plantlets at the end of using of each temperature factor. Analysis of variance revealed that the effect of temperature، genotype and interaction effects of two factors were significant on length of coleoptile at 1% probability levels. The low temperature treatments decreased the growth of coleoptile in all of the studied cultivars. Taichung and Sadri showed a significantly bigger coleoptile length at the three low temperature treatments including 13، 17، 21 and 25 C°. The percentage of coleoptile reduction was calculated form comparison of the length of coleoptile at 13 and 25 C°. The coleoptile reduction rate was lower than 10 percentages in Hashemi، Gerde and Neamat، indicating these varieties as tolerant varieties to cold stress. Second experiment was carried out on randomized complete block design with three replications. In this experiment، the seeds were placed in 25 C° for 72 h and then the temperature was adjusted to 10 C° for 96 hr. Temperature was further increased to 25 C° and treated plantlets to this temperature for 72 h. The length of coleoptile was measured in two stage contain after 10 C° for 96 hr (length 1) and 25 C° for 72 hr (length 1). The difference between these two lengths were calculated and called coleoptile regrowth. Analysis of variance indicated that the effect of genotype were significant on coleoptile regrowth. Gerde was as a tolerant variety due to percentage of reduction in coleoptile length and coleoptile regrowth.

To evaluate germination and seedling growth of safflower an experiment carried out as factorial with two factor; temperature (5, 15, and 25 °C) and salinity of sodium chloride (0, 5, 10, and 15 ds/m) based on randomized complete block design with four replications, in Dept. of horticulture of Urmia University. Results of different concentration sodium chloride on germination and seedling growth of safflower under different temperature showed significance of salinity and growth temperature level on germination rate, percent, and time to 50% germination. These factors had no effect on reduction of germination. Significance of interaction between salinity and temperature on germination index, shoot and root length, shoot and root dry weight showed different trends of them under these factors. The minimum amounts of percentage (76), rate (7.6 N/Day) of germination and longest time to 50% of germination (135 h.) were occurred at 15 ds/m of sodium chloride. But the maximum amounts of percentage (86), rate (8.6 N/Day) of germination and shortest time to 50% of germination (58 h.) were occurred at 5 ds/m same with 0 and 10 ds/m. Increasing of temperature at all levels of sodium chloride led to highest value of germination index.

The effect of environmental factors as temperature, photothermal quotient and rainfall during seed filling period (SFP) on seed weight of different species of Brassica was studied in Gonbad during 2003–2006 growing seasons. Twenty genotypes from different species of Brassica including: five genotypes of spring B. napus, five genotypes of winter B. napus, five genotypes of B. rapa, and five genotypes of B. juncea were sown at optimum sowing date recommended for the area. In all species, there was a linear relationship between 1000- seed weight and mean air temperature, photothermal quotient and rainfall during SFP. Increase in radiation accompanied with relatively moderate temperatures during SFP, hence, increased seed weight. Each millimeter increase in rainfall during SFP increased the rate of 1000-seed weight of spring and winter rapeseeds, mustard and turnip genotypes by 0.0094, 0.0247, 0.0105 and 0.0132 g, respectively. In addition, with an each day increase in duration of SFP, 1000-seed weight of spring and winter rapeseeds, mustard and turnip genotypes increased by 0.0533, 0.1682, 0.0456 and 0.0529 g, respectively. These relationships showed that winter rapeseeds genotypes had more response to favorable environmental factors during SFP. The non-significant relationship between seed number per unit area and seed weight in different species of Brassica showed that under conditions of this study sink size did not affect seed weight, but it was affected by environmental factors during seed filling period.

Global warming will affect all climatic variables and particularly rainfall patterns. The purpose of present investigation was to predict climatic parameters of Iran under future climate change and to compare them with the present conditions. For this reason, UKMO General Circulation Model was used for the year 2025 and 2050. By running the model, minimum and maximum monthly temperature and also maximum monthly rainfall for the representative climate stations were calculated and finally the effects of climate change on these variables based on pre-determined scenarios was evaluated. The results showed that averaged over all stations, mean temperature increase for spring in the year 2025 and 2050 will be 3.1 and 3.9, for summer 3.8 and 4.7, for autumn 2.3 and 3 and for winter 2.0 and 2.4 ºC, respectively. This increase will be more pronounced from North to the South and from East to the West parts of the country. Mean decrease in autumn rainfall for the target years of 2025 and 2050 will be 8 and 11 percent, respectively. This decrease is negligible for summer months. Length of dry season for the years 2025 and 2050 will be increased, respectively up to 214 and 223 days due to combined effects of increased temperature and decreased rainfall.