Determining of chilling and heat requirements of olive cultivars growing in Fars Province is important for the selection of cultivars that will exhibit satisfactory growth and development. The purposes of this study were determining the chilling and heat requirements of olive and comparison of Utah and Positive Utah Chill unit (PCU) models for determining the chilling requirements of olive cultivars. In this regard, chilling requirement of flower buds of ‘ Fishomi’ , ‘ Dezful’ , ‘ Zard’ , ‘ Dehghan’ and ‘ Shiraz’ cultivars were determined. Cuttings of these cultivars were taken during autumn when the mean temperature fell below 12º C. Cuttings were kept at 5 º C for periods of 0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 and 1800 h. Results indicated that the chilling requirements of ‘ Fishomi’ , ‘ Dezful’ , ‘ Zard’ , ‘ Dehghan’ and ‘ Shiraz’ were 900, 1000, 900-1000, 1000-1100 and 900 h, respectively. Results also showed that the PCU unit model was more efficient than the Utah for estimating chilling requirements under subtropical field conditions. Heat requirements from the end of dormancy to full bloom stage of these five olive cultivars were estimated as 199. 2, 272. 1, 245. 2, 245. 2, 321 growing degree days (GDDs), respectively. It was observed that ‘ Fishomi’ had the lowest chilling requirement and ‘ Dehghan’ obtained the highest one. Hence, ‘ Fishomi’ can be recommended for cultivation in subtropical regions.

Introduction The accumulation of chilling during the dormancy period for fruit trees is very important. Failure to chilling requirement will reduce performance and waste of resources. Successful cultivation of horticultural products depends on suitable climatic conditions. Dormancy is considered one of the most important stages in the life cycle of temperate plants. Horticulture and fruit production are one of the most important parts of the country. The bulk of the country's exports are covered with arid and frosty crops. Providing winter chilling to the temperate regions is critical to the lack of attention to this, causing the loss of capital and resources. Measuring different areas through weather stations is an effective step in understanding the climate potential of each area to understand the accumulation of cold. Considering the trend of global warming and climate change, today, the assessment of global warming has been the focus of global studies. The study indicated that a comprehensive study with more stations and long-period hourly data on cold accumulation and calibration of different estimator models was not carried out. Therefore, the present study aims to analyze the winter cold accumulation of cold regions of Iran based on CH, Utah and CP models using statistics. The longterm temperature of three hours of observation of meteorological stations has been designed and carried out. Methods and Matrial In this study, the weather temperature data during the recession period was extracted from the Iranian Meteorological Organization (IMO) from 1985 to 2013. The 9744000 hour temperature record for the three different models of estimation of cold accumulation during the dormancy period was set up from November to March. For each model, 3258000 data is provided for the hourly temperature to determine the time series of the accumulation of cold. In order to estimate the accumulation of cold in the country through the meteorological stations studied, three common models of estimation of cold accumulation, chilling hours (CH), Utah units and dynamic model (CP) were used. The non parametric Mann-Kendall method was used to process the time series changes and the validation criteria were used to calibrate different models performance of accumulation of chilling. Linear interpolation was used to convert the temperature of three hours to the hourly temperature. In this method, the temperature is collected three hours later, at a temperature of three hours, and added to the previous temperature by three-hour intervals. It should be noted that this method is used independently for each three hour period of air temperature based on the temperature before and after it. Operation of this method is provided in the Excel software programming environment for each station and each year from November to March. In order to validate different models of need for cold, MAE, MBE and RMSE validation criteria were used to determine the performancr models of chilling accumulation. Results and Discussion The output of different models showed that the pattern of the accumulation of cold influenced from the height of each region. In all models of higher stations they still have the necessary accumulation of chill. Typically, Yasuj station with a lower latitude has the higher accumulation of chiiling in the doamancr period. The structure of each model is different for quantifying the chilling requirement fruit trees. In the chilling hours model, temperatures above zero to 7. 2 are more likely to play a role in the Utah model, because temperatures above 7 to 10 are also chilling effect, so the data obtained in Utah model are higher, which can not be a strong reason for this superiority model. Therefore, it is better to match the different species of chilling requirement trees with the potential of climate and the accumulation of high-temperature multiplier for each region. The coefficient of variation in the accumulation of cold in the model of CH is higher at higher station with higher chilling. Based on the Utah model, this coefficient of variation is observed in the stations, Ghouchan, Golmakan, Mashhad and Torbat Heydarieh, and in the dynamic model at Tabriz, Sarab and Fasa stations. Estimating hourly temperatures over a long period of data based on different models shows that the highest rate of high accumulation at the beginning of the statistical period has been studied and occurred over the past decades. In fact, cold and relatively cold winters in the past have been more capable of providing more power to accumulate cold over the past decades. In the last two decades, the decrease in peak cloud accumulation has become apparent. The results of stations in Ardebil, Mako, Meshkinshahr, Khoy and Sarab with hours of freezing between 1, 000 and 1, 200 hours indicate that being located in higher latitudes can not be a reason to provide the required capital for high-demand fruit trees such as late apple, because the Extreme temperature and lower than zero degrees in the accumulation of cold do not only play a role, but also have a negative effect. So the high latitude is not a strong reason to provide the cold caaumulation deciduous with high chilling requirement. The results of the validation tests indicate that the dynamic model, according to MAE and RMSE, has a higher performance among the models. Conclusions The evolution of the long-term temperature of the observed stations for the estimation of the accumulation of cold showed that, Based on the model of cold chilling hours (CH), the accumulation of cold from 775 to 1445 hours, Based on Utah's model, the accumulation of heat from 1191 to 2121 units of heat Based on the Dynamic Model (CP), the accumulation of cold temperatures varies between 63 and 96 portions in cold and temperate regions of Iran The elevation factor of the sea level plays an important role in estimating the accumulation of cold in each of the models. In terms of time variation according to the long-term time series, the frequency of peak accumulation in the past decades has been more than recent decades. In fact, the cold season in the past has been more than a decade of cooling power. The trend of cold storm changes based on non-parametric Mann-Kendall test showed that there were significant changes in significant changes in the stations at Isfahan and Shahrekord stations at a significant level of 0. 05. Although there was no significant trend at most stations, the trend slope of the trend line at most stations is important. These conditions can be attributed to the effects of global warming through mild winters in recent decades. The results of the validation criteria of the models for estimating cold accumulation showed that the dynamic model with less error rate in the prediction of cold accumulation has a higher performance than other models. The results of this research are important in providing a comprehensive and initial model of cold accumulation in temperate and cold regions of the Iran in order to adapt the varieties consistent with the climate potential and the pattern of the accumulation of cold in each region.

Objective: Almonds are high in antioxidants, vitamin E, protein, and fiber. This nutrient-rich nut is an excellent addition to any diet since it is a versatile ingredient linked to several health benefits. The development of communications have led to a wider cultivation of temperate fruits, cultivars being selected and grown in different environmental conditions. This situation has increased the risks derived from the incomplete breaking of dormancy, and encouraged studies concerning the chilling and heat requirements of fruit cultivars for breaking dormancy and flowering. Estimating chilling and heat requirements of flower buds in fruit trees is important due to predicting flowering time for appropriate site selection to escape spring frost damage. Methods: In order to investigate the chill and heat requirements of commercial almond cultivars, a factorial experiment was planned and implemented in a completely randomized design with 3 replications in Shahrekord university lab (in 2017). The first factor included commercial almond cultivars in five levels (Mamaei, Rabi, Sefid, Shahroud 7, and Shahroud 12) and the second factor included chilling in seven levels (100, 200, 300, 400, 500, 600, and 700 hours at 4-7 °C). As soon as dormancy was induced in the buds of each cultivar, 75 branches were prepared and transferred to a refrigerator with a temperature of 4 to 7 ° C to determine the chilling requirement. The samples were taken out of the refrigerator and placed in water and sucrose solution in the greenhouse environment, and the flowering status of flower buds was examined. Results: The results illustrated that the chill and heat requirements of Sefid and Mamaei cultivars were lower than average requirements of all cultivars in this respect. Furthermore, these two cultivars had the lower chill and heat requirements than other cultivars. Also, Sefid cultivar needed 170 hours of chill requirements and 5886 growing degree hours’ heat and Mamaei cultivar needed 170 hours of chill and 7707 growing degree hours’ heat. Rabi cultivar had lower chill and heat requirements than the average of all cultivars, but in Shahroud 7 cultivar both of chill and heat requirements were high. Shahroud 7 cultivar needed to 220.5 hours of chill and 10958 of heat growth degree hours for blooming. On the other hand, Shahroud 12 cultivar was identified as a cultivar with high chilling requirements and low heat requirements. Conclusion: The minus effects of the lack of chilling for breaking dormancy in temperate fruits, both in vegetative growth, and fruit-bearing have been proved. Chilling requirements of temperate fruit cultivars have to be fully satisfied, if dormancy breaking is to result in the desired vegetative growth, and if the fruit-bearing capacity is to be fulfilled. On the other hand, in case of low chilling requirements blooming happens too early and cold temperatures produce an important loss of yield by frost.

Understanding the climatic potentials of the regions is very important for the diversity and talent of agricultural products. Barberry, one of the products of Iran, suffers from climate change and anomalies. In the present study, the phonological stages of barberry tree without any basis of field observations in Ghaen synoptic meteorological station were determined. To measure the accumulation of cooling needs based on the cold clock model and the Utah unit, the statistics of 18 valid meteorological stations from 1987 to 2017 on an hourly and daily time scale were used. The results showed that barberry needs six phonological stages to complete the growth period from early April to late November. The highest temperature requirement occurs in the ripening stage until fruit development. The cooling requirement of barberry tree in different stations varies from 1050 to 1960 hours depending on climatic conditions. Field observations showed that seedless barberry does not take on a full and commercial color if it does not meet the need for sufficient cooling. The study area was zoned according to the models of the cold clock and the Utah unit, based on which Ghaen and Zahedan stations have the highest cooling needs. Based on the validation indices of different models estimating the need for cooling, the root mean square criterion was used and the results show that the cold hour (CH) model has a higher performance due to the fact that the root mean square (RMSE) is less than the other model.