Browsing by Author "Davis, Scott"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Effects of proposals no. 20 & 37 on the men's basketball budget at Virginia TechDavis, Scott (Virginia Tech, 1993-05-05)This thesis attempted to determine whether or not Proposals No. 20 and 37 helped reduce budgetary expenses in the men’s basketball budget at Virginia Tech. Proposals No. 20 and 37 deal with telephone and recruiting expenses and only those two areas of the basketball budget were examined. Only the years from June 1990 to July 1991 and June 1991 to July 1992 were compared in the study. The telephone records were matched with recruiting files so only those calls associated with recruiting could be identified, thus indicating whether or not Proposal No. 20 was effective. The recruiting account was examined and the on-campus and off-campus expenses were separated so that it could be determined if Proposal No. 37 was effective in reducing recruiting expenses. The results of the study led to two conclusions. First, there was a slight increase in the total expenditures on telephone recruiting calls during the 1991- 92 year as compared to the 1990-91 year. Second, the total percentage of the recruiting budget for off-campus expenses increased from 1990-91 to 1991-92 although the dollar amount expended decreased.
- Using maize chromosome segment substitution line populations for the identification of loci associated with multiple disease resistanceLopez-Zuniga, Luis O.; Wolters, Petra; Davis, Scott; Weldekidan, Teclemariam; Kolkman, Judith M.; Nelson, Rebecca J.; Hooda, K. S.; Rucker, Elizabeth; Thomason, Wade E.; Wisser, Randall J.; Balint-Kurti, Peter J. (Genetics Society of America, 2019-01-09)Southern Leaf Blight (SLB), Northern Leaf Blight (NLB), and Gray Leaf Spot (GLS) caused by Cochliobolus heterostrophus, Setosphaeria turcica, and Cercospora zeae-maydis respectively, are among the most important diseases of corn worldwide. Previously, moderately high and significantly positive genetic correlations between resistance levels to each of these diseases were identified in a panel of 253 diverse maize inbred lines. The goal of this study was to identify loci underlying disease resistance in some of the most multiple disease resistant (MDR) lines by the creation of chromosome segment substitution line (CSSL) populations in multiple disease susceptible (MDS) backgrounds. Four MDR lines (NC304, NC344, Ki3, NC262) were used as donor parents and two MDS lines (Oh7B, H100) were used as recurrent parents to produce eight BC3F4:5 CSSL populations comprising 1,611 lines in total. Each population was genotyped and assessed for each disease in replicated trials in two environments. Moderate to high heritabilities on an entry mean basis were observed (0.32 to 0.83). Several lines in each population were significantly more resistant than the MDS parental lines for each disease. Multiple quantitative trait loci (QTL) for disease resistance were detected for each disease in most of the populations. Seventeen QTL were associated with variation in resistance to more than one disease (SLB/NLB: 2; SLB/GLS: 7; NLB/GLS: 2 and 6 to all three diseases). For most populations and most disease combinations, significant correlations were observed between disease scores and also between marker effects for each disease. The number of lines that were resistant to more than one disease was significantly higher than would be expected by chance. Using the results from individual QTL analyses, a composite statistic based on Mahalanobis distance (Md) was used to identify joint marker associations with multiple diseases. Across all populations and diseases, 246 markers had significant Md values. However further analysis revealed that most of these associations were due to strong QTL effects on a single disease. Together, these findings reinforce our previous conclusions that loci associated with resistance to different diseases are clustered in the genome more often than would be expected by chance. Nevertheless true MDR loci which have significant effects on more than one disease are still much rarer than loci with single disease effects. © 2019 by the Genetics Society of America.