Osteoarthrosis in a Coyote x Dog Hybrid from Nebraska

Osteoarthrosis is described in a wild, 14-year-old coyote (Canis latrans) x dog (C. familiaris) hybrid shot in southeastern Nebraska. There was ankylosis of five vertebrae, the head of the left femur was absent, and periarticular osteophytes occurred throughout the skeleton. The age is significant because wild coyotes seldom live beyond 6 years and coyote x dog hybrids are considered to be less fit for survival in the wild than coyotes.

Deer-Vehicle Crash Patterns Across Ecoregions in Michigan

Deer-vehicle collisions (DVCs) impact the economic and social well being of humans. We examined large-scale patterns behind DVCs across 3 ecoregions: Southern Lower Peninsula (SLP), Northern Lower Peninsula (NLP), and Upper Peninsula (UP) in Michigan. A 3 component conceptual model of DVCs with drivers, deer, and a landscape was the framework of analysis. The conceptual model was parameterized into a parsimonious mathematical model. The dependent variable was DVCs by county by ecoregion and the independent variables were percent forest cover, percent crop cover, mean annual vehicle miles traveled (VMT), and mean deer density index (DDI) by county. A discriminant function analysis of the 4 independent variables by counties by ecoregion indicated low misclassification, and provided support to the groupings by ecoregions. The global model and all sub-models were run for the 3 ecoregions and evaluated using information-theoretic approaches. Adjusted R2 values for the global model increased substantially from the SLP (0.21) to the NLP (0.54) to the UP (0.72). VMT and DDI were important variables across all 3 ecoregions. Percent crop cover played an important role in DVCs in the SLP and UP. The scale at which causal factors of DVCs operate appear to be finer in southern Michigan than in northern Michigan. Reduction of DVCs will likely occur only through a reduction in deer density, a reduction in traffic volume, or in modification of sitespecific factors, such as driver behavior, sight distance, highway features, or speed limits.

Xenia Effects on Quality of Maize Female Inbred in Production of Hybrid Seeds

In Maize (Zea maize L.), cost of hybrid seed production is directly related to the yield and quality of seed obtained per hectare of female parent. It is also important to consider the effects that a male parent can exert on the development of hybrid seed in the female parent. This effect is known as xenia. The objectives of this study were to evaluate xenia effects on 1) yield as 80K units, 2) germination of the hybrid seed and 3) susceptibility of the hybrid seed to mechanical damage. One female inbred and four male inbred lines were selected from a parent list of hybrids. The experiment was designed to allow individual cross pollination between each male inbred and the female inbred line. For use as a control, the female inbred was allowed to self pollinate. Experiments were conducted in Illinois and Iowa during 2008 and 2009 and in Nebraska during 2009. A significant inbred effect was detected on yield as 80k (α=0.001). The selfed female and pollination with male inbred B resulted in lower yields of hybrid seed. For germination, a significant inbred effect was detected (α=0.001), but was due to lower germination percentage of seed produced on the selfed female. All hybrid combinations resulted in higher germination percentages with no significant differences among hybrids. The inbred x mechanical damage interaction was significant (P=0.04) for effects on cold saturated soil germination tests. Use of inbred B resulted in a two-percentage-point reduction in cold germination when treated with the impact simulator. In a maize seed company, the production research group provides yield estimates for production of new hybrid combinations. Results from this study indicate that using only the female inbred yield may provide inaccurate estimates. Therefore to improve yield estimation, experiments should be designed to include male inbreds. Male inbreds can also impart a negative effect to the hybrid seed on tolerance to mechanical damage, thus lowering quality and increasing seed discard. When testing for hybrid seed germination, there is no need to consider distinct hybrid combinations. Female inbreds can be grown in open-pollinated fields to avoid loss of vigor observed with selfing. Advisor: George Graef