Liens tolerate environmental stresses utilizing is one of the applicable technologies in sustainable agriculture. Since occurrence of a suitable winter for studing and selection of cold/frost resistance on breeding materials is one year out of ten, therefore laboratory methods complementing field data provide a reasonable solution for this propose. This research was conducted in Khorasan Agri. Res. Center. Mashhad. Using RCBD in three replications during 1380-81. Treatments consisted of twenty promising genotypes of uniform regional yield trail (cold area). Genotypes suits low temperature regions will be introduced based on generated results from this investigation. Using crown Freezing method, experimental genotypes were treated with -20. C temperature under controlled conditions. Survival percentage was computed. Results indicated that genotypes No.9 (C-78-9) and No.7 (C-78-7) had highest (98.33%) and lowest (66.67%) survival percentage respectively. The minimum Crown Moisture Content was detected in line No. 9 (C-78-9) and there was no significant difference for the same trait between genotype No.7(C-78-7) and other superior genotypes. A high negative correlation (r=-0.701) was observed between survival percentage after exposing to frost and crown moisture content. Ear primordia development stage was one of the characters which had also a significant correlation with survival percentage (r=-0.619). Significant correlation between survival percentage and days to heading (r=-0.207) and days to physiological maturity (r =-0.028) was not observed. Correlation between survival percentage and collected cold damage data from experimental fields over five low temperature regional stations was highly significant (r=0.416), therefore it may be concluded that Crown Freezing Method and subsequent computing of survival percentage is a reliable method for estimating wheat frost/cold tolerance in natural conditions.

It should now be beyond doubt that blastocyst culture results in better pregnancy rate (PR). This calls for fewer embryos to be transferred, and indeed blastocyst culture is of most value when the intention is to put back one embryo at a time.The PR with one top-grade blastocyst is 45-65% in different studies. If two top-grade blastocysts are transferred, the PR usually does not differ, but the rate of multiples increases manyfold. Given a good Freezing programme, the cumulative PR after one fresh and one frozen single blastocyst transfer exceeds that of a fresh two-blastocyst transfer.Culture can be done open, or in drops under oil. The use of a low-oxygen (”three-gas”) incubator is beneficial.ET shall be performed on day 5. PR decreases if fresh ET is done on day 6, but embryos frozen on day 5 or day 6 perform equally when transferred in a freeze-thaw cycle.Preferrably, this should be a spontaneous or a FSH stimulated cycle. Oestrogen / progesteron cycles may result in a higher rate of miscarriages.Only top-grade or next to top-grade blastocysts should be frozen to ensure good results. The fact that there are fewer day 5 embryos to be frozen than after 2-3 days culture is an advantage rather than the opposite, as the PR per embryo is higher.Puncturing of the expanded blastocyst is crucial and can be done just as well with a needle as by laser. Most studies have shown that vitrification is superior to slowFreezing, but these studies often have surprisingly poor results for slow-Freezing with low surviving rates and low PR. At our unit, 76% of thawed blastocysts survive and are transferred with a PR after transfer of a single blastocyst of 56%, which is the same as the comparable fresh transfer.Where three or more embryos are transferred, there is no advantage of blastocyst culture. Indeed, it only results in even more multiple pregnancies.

Maintaining the nutritional quality and preserving pomegranate seeds is a major challenge due to the fast degradation of the texture, color and overall quality of pomegranate seeds. In order to investigate the Freezing of coated pomegranate seeds with chitosan and determine its quality during Freezing storage, an experiment was conducted, in a factorial arrangement in a completely randomized design with three replications. Factors were: chitosan at three levels (0, 1 and 2%), Freezing temperature at two levels (-14 °-24 ° C) and time at 5 different storage times (14 days, 30 days, 60 days, 90 days, and 120 days). The highest tissue firmness was observed for 14 days of storage under both chitosan concentrations. Interaction of different levels of chitosan coating and time had an increasing effect on the color component changes, so that the most color changes in the brightness (L*), redness (a*), and yellowness (b*) was related to the use of chitosan coating 2%, were maintained at 60 days. The highest total soluble solids were related to 1% chitosan under 4 months of storage at-14° C. Maximum total acidity (1. 36 mg / L) was also attributed to coated pomegranate seeds during 120 days of storage under both Freezing temperatures of-14° C and-24° C. The results of mean compares showed that the total phenol stability under Freezing temperature was higher at-14° C and after 120 days of storage, more phenol content was observed in the seeds in-24 C. The overall results indicated a positive effect of chitosan on maintaining the quality of pomegranate seeds during Freezing, and the Freezing temperature of-24 ° C with decreasing color changes during storage, played an important role in reducing metabolic activity and reducing anthocyanin degradation and was effective in maintaining fruit quality.

Introduction: Oocyte Freezing is the only method to preserve the reproductive capacity for woman at risk of losing it because of premature ovarian failure, pelvic diseases, surgery, radiotherapy or chemotherapy treatments related to the ovary . But oocyte storage has faced technical difficulties compared with sperm or embryo cryopreservation because of specific structure of oocyte. The purpose of this study is investigated the morphological survival rate and developmental competence of thawed oocytes after cryopreservation by slow Freezing or vitrification.Materials and Methods: Female mice superovulated with intraperitoneal injection of PMSG and HCG. Ovulated MII mouse oocytes were allocated to the three groups as slow frozen, vitrified and control groups. Vitrification performed using ethylene glycol (EG) and dimethyl solfoxide (DMSO) and slow Freezing using propanediol (PROH). After thawing the surviving MII oocytes in both cryopreserved and control group were inseminated for in vitro fertilization (IVF) and their developmental ability were compared.Results: The survival rate of post thawed mature oocytes in vitrification group was 73.3% and in the slow Freezing was 33.3%. Then following IVF, the percentage of cleaved embryos in control, vitrification and slow Freezing groups was 64%, 25% and 20%, respectively.Conclusion: The result showed that survival rate after thawing in vitrification was greater than slow Freezing while the cleave embryo rate did not. Vitrification seems to be an effective, easy and rapid method for the cryopreservation of mouse MII oocytes.

Objective: Oocyte Freezing is the only method to preserve the reproductive capacity for woman at risk of losing it because of premature ovarian failure, pelvic diseases, and surgery, radiotherapy or chemotherapy treatments. But oocyte storage has faced technical difficulties compared with sperm or embryo cryopresevation because of specific structure of oocyte. The purpose of this study is investigate on the morphological survival rate and developmental competence of thawed oocytes after cryopreservation by slow Freezing or vitrification.Materials and Methods: Female mice super-ovulated with intraperitoneal injection of PMSG and HCG. Ovulated MII mouse oocytes were allocated to slow frozen and vitrified and control groups. Vitrification using ethyleneglycol (EG) and dimethyl solfoxide (DMSO) and slow Freezing using propanediol (PROH) After thawing the surviving MII oocytes in both cryopreserved and control group were inseminated for in vitro fertilization (IVF) and their developmental ability was compared.Results: The survival rate of post thawed mature oocytes in vitrification group was 73.3% and in low Freezing was 33.3%, (P<0.01). Then after IVF, The percentage of cleaved embryos in control, vetrification and slow Freezing groups was 64%, 25% and 20%, respectively (p>0.05).Conclusion: The result showed that survival rate after thawing in vetrification was greater than slow Freezing, but the cleaved embryo rate did not differ significantly between the two different cryopreservation methods