A study of three barley varieties in mixtures and pure stands

A primary objective in plant breeding programs is to develop high yielding varieties that have consistent performance. Selection for pure line varieties has been responsible for much of the genetic improvement in self-fertilized crop plants. Pure line varieties are usually very productive and are highly uniform in maturity, disease resistance, and market quality. Recently, multiline populations or mixtures have been suggested by several plant breeders to stabilize and perhaps increase yield (1, 9, 12, 13, 23). Mixtures might offer greater protection against diseases and insects and provide a broader adaptation to environmental conditions, thereby minimizing unfavorable genotype x environment interactions (12, 23). Conclusive evidence has been presented which indicates that an interaction exists among genotypes. For example, \u27Vaughn\u27 barley (Hordeum vulgare L.) was found to be higher yielding than \u27Atlas\u27 in pure stands but lower yielding in mixtures (14-). Hartmann and Allard (11) found that this competition effect was present at intermediate levels of fertility and moisture but not at higher moisture levels. Competition effects for light and nutrients in Phalaris tuberosa L. and Lolium perenne L. were observed by Donald (5). Other work suggested a cooperative or synergistic effect in a few varieties of rice (Oryza sativa L.) (20), certain genotypes of barley (9), and between flax and linseed (Linum usitatissimum L.) varieties (10). A decrease in yield of mixtures compared to the mean of the component varieties grown in pure stands has been observed in lima beans (Phaseolus lunatus L.) (1) and hard red winter wheat (Triticum aestivum L. em. Thell.) (21). Results from experiments with various crop plants showed no difference between mixtures and pure stands for yield (4, 6, 7, 17, 22). Suneson and Wiebe (24) indicated that the performance of a variety mixture cannot always be accurately predicted by its performance in pure stands. The Montgomery effect (15) further implies that a particular genotype may be inferior in yield in pure stands but superior in competition. Since varieties differ in their response to the environment and their ability to compete for nutrients and other growth factors, mixtures may be of value for more efficient production. To augment various findings related to the performance of mixtures, three barley varieties were studied in pure stands and mixtures. The objectives of this study were: 1. To determine if yields of mixtures of barley varieties differ from the mean yield of the varieties grown in pure stands; 2. To determine if mixtures provide a stabilizing effect by decreasing genotype x environment interactions; 3. To measure competition effects of yield components and other agronomic characters of variety mixtures by deviations from the mean of their components grown in pure stands; and 4. To determine if the performance of the varieties in mixtures is predictable from their performance in pure stands

Federal Involvement in Education Policy: An Analysis of Race To The Top

The purpose of this study is to trace federal involvement in public K-12 education policy and to determine its effectiveness. Specifically, I present a historical analysis of federal education policy leading to the passage of Race to the Top (RTTT) in 2009. My goal is to show that, although the federal government has grown more involved in education policy, especially from the late 1980s (following the 1983 publication of A Nation At Risk that showed the failings of the nation’s schools) until present, actually students in the K-12 public education system have not progressed as the federal government had hoped. The measurement of progress, Adequate Yearly Progress (AYP), has not been met in many states as set forth in the legislation No Child Left Behind (NCLB), passed by the U.S. Congress in 2001 and signed by President George W. Bush in 2002, that set a goal of all students reaching proficiency or advanced in reading and mathematics by 2014. Because of the unrealistic expectations and no additional funding to reach the set goal, many scholars called the law an unfunded mandate and most educators grew weary of trying to meet the goal. As a result of the unfavorable education climate created by NCLB, the U.S. Congress offered relief in the form of RTTT, a grants reward program, passed by the U.S. Congress and signed into legislation by President Barack Obama in 2009. That program offered $4.35 billion to states whose applications were accepted over other states applications in order to provide funding for creative educational programming within their borders. But, my study shows that the additional funding helped improve AYP modestly or insignificantly as shown in particular by the District of Columbia, which is highlighted in this study. Finally, my study offers a survey of teachers and administrators in a prominent school district in St. Louis County, Missouri, that confirms that educators are against the notion of relying on an-end-of-the year state assessment to show evidence of student achievement and the notion of tying teachers’ and administrators’ salaries to student test scores, both of which are elements of RTTT

A semianalytical satellite theory for weak time-dependent perturbations

The modifications of the semianalytical satellite theory required to include these 'weak' time dependent perturbations are described. The new formulation results in additional terms in the short periodic variations but does not change the averaged equations of motion. Thus the m monthly terms are still included in the averaged equations of motion. This contrasts with the usual approach for the strongly time dependent perturbations in which the m monthly (or m daily, if tesseral harmonics are being considered) terms would be eliminated from the averaged equations of motion and included in the short periodics computation. Numerical test results for the GPS case obtained with a numerical averaging implementation of the new theory demonstrate the accuracy improvement

Welcome from the New SLPKC Chairs

Greetings! Please allow me to introduce myself as one of your co-chair elects for the Student Leadership Programs knowledge community (SLP KC). I am both honored and humbled to have been elected to this position and I look forward to serving the SLP KC to the best of my ability. To share a bit about myself, I have been a member of the leadership within the SLP KC for the past three years as the conference team leader. Those responsibilities have included collaborating with the coordinators of tile pre-convention workshop, sponsored programs, mentoring program, graduate support network, community/ graduate fair, and open meeting. I have enjoyed this immensely and it served as a catalyst for running for the co-chair position

An Examination of Mentoring Relationships and Leadership Capacity in Resident Assistants

The leadership capacity of resident assistants can be impacted by many experiences, including involvement in mentoring relationships. The purpose of this study was to examine if and how resident assistants’ leadership capacities are influenced by participating in these relationships. A sample of 6,006 resident assistants was analyzed using data from the 2009 Multi-Institutional Study of Leadership. An adapted version of Astin’s Input-Environment-Outcome college impact model was used as the conceptual framework, and the Social Change Model of Leadership was used as the theoretical framework. Overall findings revealed that resident assistants who participated in mentoring relationships exhibited significantly higher leadership capacities than those who did not, regardless of the mentor-protégé demographic factors. Also included are implications for practice and future recommendations

Welcome from the SLPKC Chairs (2013)

This is one of our most important newsletter issues. In Orlando, we hope you take advantage of the opportunities to engage with SLP KC members, our leadership team, and volunteer to become more involved with the KC. In addition, we welcome you to inquire about becoming a leadership team co-coordinator or team member. At each conference, we host an annual member meeting where we disseminate our annual awards, showcase our leadership team, and brainstorm about leadership practices Think Tank style

Book Review: Student Engagement Techniques: A Handbook for College Faculty

Publisher Description: Keeping students involved, motivated, and actively learning is challenging educators across the country, yet good advice on how to accomplish this has not been readily available. Student Engagement Techniques is a comprehensive resource that offers college teachers a dynamic model for engaging students and includes over one hundred tips, strategies, and techniques that have been proven to help teachers from a wide variety of disciplines and institutions motivate and connect with their students. The ready-to-use format shows how to apply each of the book\u27s techniques in the classroom and includes purpose, preparation, procedures, examples, online implementation, variations and extensions, observations and advice, and key resources

Social Justice for These Kids? A Book Review of \u3cem\u3eThese Kids: Identity, Agency, and Social Justice at a Last Chance High School\u3c/em\u3e

This review of the book These Kids summarizes the text\u27s key points, including elements of the participatory action research on which the author bases her writing as well as pertinent elements of history and education theory relating to underserved students in the continuation high school system. Agency, social justice, and equitable education opportunity are key ideas addressed in this text and review