Too often crop production is facing with different intensity of cold damage. In some years the damage is severe and has a large social and economic consequence. Therefore, selection and introduction of cold tolerant cultivars is very effective in reducing cold damage and increasing crop production. Frequently, in WINTER safflower yield trails in Isfahan province, depending on the intensity of WINTER cold, different degrees of damage are observed. Cold tolerance study of safflower was conducted in Isfahan province in central Iran during 2007-2008. In this experiment, 20 safflower genotypes were compared in a randomized complete block design with four replications. The effect of genotype on the SURVIVAL rate, the length of the rosette and ripening period, and their corresponding GDD, plant height, 1000 seed weight, seed yield, and oil content was significant at the 1% probability level. The correlation coefficients between the SURVIVAL rate with seed yield, length of the rosette period, and corresponding GDD were positive and significant. The correlation coefficient between the SURVIVAL rates with 1000 seed weight was negative and significant. Covariance analysis showed that Parnian and KW4 had the highest and lowest seed yield with 79 and 7. 9% WINTER SURVIVAL, respectively. According to the results, genotypes with a longer rosette period such as Parnian, Varamin 295 and Zarghan 279 showed more tolerance to cold damage.

An investigation was carried out in order to study the genetic variation of barley genotypes in terms of WINTER SURVIVAL, LT50 and leaf soluble carbohydrates under field and greenhouse conditions using 40 barley genotypes in the research station and greenhouse of Faculty of Agriculture, University of Tabriz, Iran. The field evaluation was performed in the form of randomized complete block design in two years and percentage of WINTER SURVIVAL was estimated. Multivariate analysis of variance indicated significant differences among genotypes for the traits measured in greenhouse and laboratory. Combined analysis of variance showed significant differences among genotypes for percentage of WINTER SURVIVAL, but the effects of year and genotype ´ year interaction were significant for this character. The greenhouse experiment for percentage of plant SURVIVAL was carried out in the form of split plot design on the basis of randomized complete blocks with two replications. Barley genotypes were assigned in subplots and five freezing temperatures (-8, -11, -13, -15 and -17oC) were assigned in main plots. Other traits measured in the greenhouse, such as LT50, percentage of seedling dry weight, soluble carbohydrates content before and after hardening and leaf length and width were analyzes based on randomized complete block design. Significant differences were observed among barley genotypes in terms of SURVIVAL percentage at temperatures -8, -11, -13, -15 and -17pC, LT50, percentage of seedlings dry weight, leaf width and the soluble carbohydrates content after hardening. The heritability of field SURVIVAL percentage, LT50 and leaf width were high. The heritability of soluble carbohydrates content after hardening and the percentage of seedling dry weight were moderate. The highest and lowest heritability were observed at temperatures -8oC and -17oC, respectively. Percentage of SURVIVAL at temperature -15oC had the largest squared genetic coefficient of variation and other traits had low squared genetic coefficient of variation. It can be concluded that genotype #38 (Athenise) was susceptible to cold stress and considerable number of genotypes had desirable characteristics for cold tolerance from which genotypes #36 (Schulyer) and #15 (EC83-12) can be recognized as more cold tolerant genotypes with regard to percentage of WINTER SURVIVAL and LT50.

The overWINTERing conditions and cold tolerance of the Lime butterfly, Papilio demoleus L., are relatively unclear. In the present study, overWINTERing pupae were collected over several months, and changes in supercooling point (SCP), cold-hardiness, and body color were investigated. Also, some eggs were collected and reared in the laboratory, and then pupae were kept for 1-4 weeks at 0, 5, and 15 °C, and the changes in SCPs were studied. Shelters were prepared and installed in the field to check the overWINTERing sites. Also, the digestive tract was investigated before and at the beginning of the overWINTERing phase. The results showed that the SCP gradually decreased from -9 to -13 °C during the autumn months, and in lab-reared pupae treated at 0-5 °C, the SCP was reduced to -13 °C. None of the pupae survived at temperatures below the SCP, so this species uses a freeze avoidance strategy. As the weather gets cold, the color of most of the pupae (76.19%) tends to brown, while in the summer months, more than 80% of the pupae are green. The overWINTERing pupae emptied their ingested foods, and the contents of their digestive system before emptying contain Pseudomonas and Enterobacter species, both of which can act as ice nucleators. Ultimately, the relationship between these factors in adapting the pest to low temperatures was discussed.

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Background: Vascular access (VA) is a prerequisite for initiation of hemodialysis (HD) in patients with end- stage renal disease (ESRD). Frequency and potency of V A types are varibus in different societies. We have done this study to achieve this goal. Materials and Methods: This descriptive retrospective study was performed over two months (august and September 2003) iq four HD centers in Isfahan, Iran. All of the patients who were treated with HD for more than 1 month were studied for the number, type of V A and some demographic factors. The questionnaires were completed at the patient"s bedside. Results: There were 320 patients. (199 male and 121 female). Mean age was 50.64± years. Among 412 permanent VAs which were created in the duration of HD, only 4 and 7 of them were graft and dual _ lumen cuffed catheters, respectively. All of the others were arterio venous fistula (AVF).The mean number of created permanent VAs in females was more than males. It was increased by some factors such as increasing the duration of HD, increasing the interval between creating permanent VA and initiation of HD. Although the latest was not statistically significant. 1 Year, 2-year, 3-year and 5- year SURVIVAL of AVF was 80%, 78%, 73% and 69%, respectively. Primary failure of AVF was. 13%. Conclusion: Regarding the statistics of other centers, SURVIVAL of AVF was low in Isfahan. The prevalence of grafts & dual - lumen cuffed catheters is lower than other countries. The majority of our patients use AVF as a VA. The earlier the patient is encouraged to create a permanent VA before initiation of HD, the AVF SURVIVAL is higher.

Pureline selection was applied in Synthetic Hexaploid Wheat populations (SHW), obtained from irradiated seeds with 150 Gy gamma rays and compared with their corresponding controls. The selection was performed in progenies of 20 initial plants from three amphiploids (8 from SHW32, 4 - SHW106 and 8 - SHW107) generating 19 M1-3 and 19 C2-5 lines. Two families did not survive WINTER in the first year. All selected lines expressed high germination, intermediate type of growth in WINTER and good seed set in the field conditions. The irradiation of seeds did not influence the germination and WINTER SURVIVAL of the SHW plants. The response to direct selection was based on the mean performance of progenies for grain number and kernel weight per main spike and the selected elite plants in M3 and C4-5 generations. The coefficient of heritability and genetic advance for these traits were highest in SHW106, followed by SHW32. SHW107 displayed the largest morphological variability and sterility during the investigated period. All synthetics formed long, but sparse ears with seed fertility being lower than their tetraploid parents, but elite plants of SHW32 and 106 were equaled to tetraploid parent No 45432 on grain weight per major spike in 2013. Seed irradiation with 150 Gy gamma rays did not cause any effects on the two investigated traits. The selected subset of 10 lines from the three amphiploids represents a source of spike productivity for use in wheat breeding programs to enhance yield potential.

Introduction: Climate change is expected to have impacts on ecosystems worldwide. During the last 50 years, the greatest warming trends have been observed in WINTER months and significant increases in both the occurrence and duration of WINTER warming have already been reported. In general, predicted future climate change scenarios will result in less than optimal cold acclimation conditions, leading to decreases in freezing tolerance and predisposition of plants to WINTER injury. Nonetheless, it is not clear whether water stress induced during cold hardening is of high importance in inducing freezing tolerance in plants or it is an integral part of typical cold hardening process. Since rapid and effective assessment of plant cold tolerance is important for researchers and also field trials have no regular process and have high error, different kinds of artificial freeze tests such as SURVIVAL percentage test and regrowth after imposing stress have been developed. Materials and Methods: In order to evaluate the effect of drought stress on plant freezing tolerance of viola, a factorial experiment was conducted based on completely randomized design with three replications in faculty of Agriculture, Ferdowsi University of Mashhad. Experimental factors include three water treatments (80% FC, 60 % FC and 40% FC) and 10 temperature levels (Control, from zero to-24 with 3 ° C intervals). Pansy seeds sown in a nursery in the summer of 2015 and after reaching the five-leaf stage in the fall plants were transferred to the pots. After the potted plants spend cold acclimation in nature conditions, plants were subjected to water stress including control (80% FC), 60% and 40% FC for two weeks. After drought stress, whole plants were sampled for freezing tolerance assessment and they were transferred to the freezer thermos-gradient. After applying the stress, electrolyte leakage, lethal temperature 50 according to the electrolyte leakage percentage (LT50el) were measured. One months later, SURVIVAL percentage, lethal temperature 50% of plant according to the SURVIVAL percentage (LT50su), leaf area, number of flower and bud, dry weight (dry weight of vegetative, reproductive, root and total) and reduced dry matter temperature 50 (RDMT50) were evaluated. Results and Discussion: Electrolyte leakage percentage (EL %) and SURVIVAL (%) were significantly (p ≤ 0. 01) affected by irrigation treatments in the freezing conditions. By lowering the temperature from 20 to-24 ° C, the EL% significantly increased in three irrigation treatments and it increased in 80% FC compared to 60% (by 16%) at-24° C. plants under 60% FC treatment exhibited higher baseline freezing tolerance (LT50 of − 18. 4 ° C) compared to 80% FC (LT50 of − 11. 8 ° C). Treated plants (except 80% FC) were able to tolerate lowering the temperature to-21° C. Lowering the temperature to-24° C caused the total mortality. According to the LT50su index, 60% FC treatment was less than compared to other treatments. Leaf area significantly increased by 16%, respectively, when plants were under water deficit (60% FC) compared to 80% FC at 0 ° C. The maximum number of flower were seen in 60% FC at – 3 ° C and the maximum number of bud were observed at 0 ° C. The results showed that dry weight was significantly (p ≤ 0. 01) increased by drought stress in the freezing conditions. Plants under 60% FC at 0 ° C had the highest increase (55, 62 and 64%, respectively) dry weight of vegetative, reproductive and total growth, respectively compared to control. By lowering the temperature to-18 ° C in 80% FC vegetative, reproductive and root growth decreased (36, 38 and 42%, respectively) compared to control plants. RDMT50 significantly affected by drought stress. There were significantly correlation between EL with LT50el and RDMT50 (r =0. 25* and r = 0. 72**, respectively). In total, plants under 60% FC showed highest freezing tolerance compared to the other treatments. Conclusions: In the current study, we found that the greatest gain in freezing tolerance was associated with cold and that the effect of drought stress on freezing tolerance varied with temperature. Drought stress resulted in an improvement in freezing tolerance of viola (lower LT50). Among the different parameters evaluated, 60% FC treatment at 0 ° C most consistently induced increases in SURVIVAL percentage, reproductive and vegetative growth which suggested a synergistic effect between drought exposure and low temperature. Higher dry weight of viola plants may contribute to better plant overWINTERing capacity. In addition, future research should explore the effect of repeated mild drought events on freezing tolerance of acclimated plants, by using strategies such as wilt-based irrigation scheduling, partial root zone drying, and deficit irrigation.

Cold tolerance of 14 wheat cultivars under field conditions was investigated. Cultivars including Anza, Bezostaja, Pishtaz, Tous, Zagros, Zarrin, Shahryar, Falat, Ghuds, Glenson, Maroon, Navid, Niknejad and MV-17 were planted in a complete randomized block design with 3 replications in the experimental station of college of agriculture, Ferdowsi University of Mashhad in autumn of 2004-2005. Growth stage of plants and chlorophyll content were measured before cold and WINTER SURVIVAL, plant height, yield components and seed yield were measured at the end of growing season. Results showed that despite of a relatively extreme cold (-9.2oC), most of the cultivars tolerated WINTER and only Zagros and Maroon with 93.3 and 73.3%  WINTER SURVIVAL, respectively, suffering WINTER damage. Toos cultivar had the highest seed yield and Maroon and Zagros cultivar had the lowest yield. Seed yield had the positive correlations with spikelet number per spike (r=0.85***), and 1000-seed weight (r=0.85***). Results of this experiment suggested that Glenson had the most level of cold tolerance and Maroon was the coldest sensitive cultivar.