Generation of Doubled Haploid Barley by Interspecific Pollination with Hordeum bulbosum.

The generation of doubled haploid barley plants by means of the so-called "Bulbosum" method has been practiced for meanwhile five decades. It rests upon the pollination of barley by its wild relative Hordeum bulbosum. This can result in the formation of hybrid embryos whose further development is typically associated with the loss of the pollinator's chromosomes. In recent years, this principle has, however, only rarely been used owing to the availability of efficient methods of anther and microspore culture. On the other hand, immature pollen-derived embryogenesis is to some extent prone to segregation bias in the resultant populations of haploids, which is due to its genotype dependency. Therefore, the principle of uniparental genome elimination has more recently regained increasing interest within the plant research and breeding community. The development of the present protocol relied on the use of the spring-type barley cultivar Golden Promise. The protocol is the result of a series of comparative experiments, which have addressed various methodological facets. The most influential ones included the method of emasculation, the temperature at flowering and early embryo development, the method, point in time and concentration of auxin administration for the stimulation of caryopsis development, the developmental stage at embryo dissection, as well as the nutrient medium used for embryo rescue. The present protocol allows the production of haploid barley plants at an efficiency of ca. 25% of the pollinated florets.

First-year success in a nursing baccalaureate plan of study: A descriptive research study.

BACKGROUND: Predicting students' aptitude for post-secondary success remains a widely studied topic. This descriptive study explored demographic variables contributing to success in quantitative courses required by the nursing degree plan. Identification of an "at risk" student profile may inform interventions with which to support attainment of an academic degree. OBJECTIVE: The purpose of this study was to examine the associations between demographic characteristics and successful completion of baccalaureate nursing courses thought to enhance quantitative reasoning skills: first-year math, first-year chemistry, and second-year pathopharmacology nursing. METHODS: This retrospective analysis accessed 4521 academic records of students who took these three courses at a United States university sometime between Fall 2008 and Fall 2015. De-identified student data included course grades, gender, full-time study, income, marital status, first generation, secondary school (also known as high school) location, dual credit, and high school and university grade point averages. Descriptive statistical analysis was conducted to describe the important features of the data. RESULTS: Of the 4521 records, 2556 undergraduates (57%) passed the courses in which they were enrolled. Among successful students, females outnumbered males (66%), ages ranged from 20 to 24 years, 86% were classified as low income, 54% fit the designation of first generation, and 12% earned dual credit (university credit during secondary school). Our data demonstrate a positive relationship between dual credit and success, with the strongest correlation (0.62) noted for students in pathopharmacology. CONCLUSION: In the baccalaureate-nursing plan of study, courses thought to enhance students' quantitative reasoning skills remain difficult for some to successfully complete. We conclude that the more successful students tend to be older, have a higher income, and a higher high school grade point average, while those less successful are directly out of high school and have not earned dual credit.