Association analysis, genetic diversity and population structure of barley (Hordeum vulgare L.) under heat stress conditions using SSR and ISSR markers linked to primary and secondary metabolites.

BACKGROUND: Barley is one of the major cereal crops, which can provide a significant source of genes for stress tolerance due to its high diversity and adaptability. Metabolite traits are considered to be significant for adaptation of barley to heat stress. METHODS AND RESULTS: In the present study, genetic relationships between 120 barley genotypes were determined with 50 simple sequence repeat (SSR) and 26 inter simple sequence repeat (ISSR) markers under heat stress and non-stress conditions. Moreover, genetic diversity of barley accessions was investigated using the studied markers covering 7 chromosomes of barley. RESULTS: In general, 153 and 85 polymorphic alleles were detected for SSR and ISSR and number of the observed polymorphic allele varied between 2-9 and 2-6, with an average of 3.26 and 3.26 alleles per locus, respectively. Markers of Bmag0223, GBMS180/180, HVM7, ISSR22, ISSR25, and ISSR48 were the most informative due to their high polymorphism information content value demonstrating that putative techniques utilized in this research can be powerful and valuable tools in breeding program of barley. Association analysis was performed between 9 important traits and SSR and ISSR markers using four statistical models. The results revealed that the model containing both population structure (Q) and general similarity in genetic background arising from shared kinship (K) factors reduced false positive associations between markers and phenotypes. CONCLUSIONS: According to the results, some of markers related to more than one trait under normal conditions (ISSR31-2, HVM62, and GBMS180/180) and heat stress conditions (ISSR20-5, EBmac635, HVM14, and ISSR37-3) were determined, which can be considered to be the most interesting candidates for further studies and simultaneously will provide a useful target for the future breeding programs, such as marker-assisted selection (MAS).

The Relationship between the Time of Endoscopy and Morbidity and Mortality Rates in Patients with Upper Gastrointestinal Bleeding.

BACKGROUND: This study was done to evaluate the relationship between the time of endoscopy in patients with upper gastrointestinal bleeding with morbidity and mortality rates of patients at the Al Zahra Hospital emergency room. MATERIALS AND METHODS: In a cohort study, 1152 patients at 2014 and 2015 have been hospitalized due to gastrointestinal bleeding in Al Zahra Hospital, were selected and demographic and clinical information and day and time of endoscopy and hospital mortality and fewer deaths than a month after discharge were studied, and prognosis was analyzed in terms of day and time of endoscopy. RESULTS: Nine hundred and seventy-three cases (84.5%) of endoscopy were performed during the working days and 179 (15.5%) were performed on holidays. Moreover, 801 cases (69.5%) of endoscopy were done in the morning and 351 cases (30.5%) were performed in the evening and night shifts. The day and time of endoscopy had no significant effect on mortality in hospital and less than a month after but hospital death in whom underwent endoscopy by fellowship was significantly higher (P = 0.004). CONCLUSION: Endoscopy in nonholiday and holiday days and the time of endoscopy has no significant effect on hospital mortality 1 month after discharge. However, other factors such as endoscopy by attendant or fellowship, time between admission to endoscopy, age and sex of the patients, etc., were significantly effective on in-hospital mortality and death 1 months after discharge. Also faster and sooner endoscopy cannot reduce rate of blood transfusions or reduce the length of hospital stay but faster endoscopy of patients can reduce the risk of in-hospital death.

Mapping QTLs for traits related to salinity tolerance at seedling stage of rice (Oryza sativa L.): an agrigenomics study of an Iranian rice population.

Rice (Oryza sativa L.) is one of the most important food crops in the world, especially in Asian countries, and salinity is a major constraint to the sustainability and expansion of rice cultivation. Genetically improving salt tolerance of rice is a highly important objective of rice breeding programs. Traits such as salt tolerance are quantitatively inherited. Hence, mapping quantitative trait loci (QTL) with molecular markers can be very helpful to plant breeders in the field of agricultural genomics (AgriGenomics). In this investigation, QTL analysis of physiological traits related to salt tolerance was carried out using F2:4 population of rice derived from a cross between a salt-tolerant variety, Gharib (indica), and a salt-sensitive variety, Sepidroud (indica). A linkage map based on 148 F2 individuals was constructed with 131 SSR markers and 105 AFLP markers, covering 2475.7 cM of rice genome with an average distance of 10.48 cM between flanking markers. A total of 41 QTLs for twelve physiological traits under salinity stress were detected distributed on all rice chromosomes, some of them being reported for the first time. Also, overlapping of QTLs related to salt tolerance were observed in this study. Some of the identified QTLs on specific chromosomal regions explaining high phenotypic variance could be used for marker-assisted selection (MAS) programs. New QTLs retrieved in this study play an important role in growth of rice at seedling stage in an Iranian local population under high salinity conditions.