Studies were conducted to evaluate the effect of stratification and seed age on percent seedling emergence of Penstemon. Emergence differences occurred between the eight Penstemon selections, as well as between seed stratification treatments and seed age. Seed stratification significantly increased emergence. Emergence varied from 0% with 1-year-old seed of Penstemon digitalis with no stratification, to 72.8% emergence with 2-year-old seed of P. angustifolius with 10 weeks of stratification. Seedlings from 3- to 4-year-old seed generally emerged as well as or better than with 1- and 2-year-old seed. Percent emergence varied significantly with stratification, seed age, and species. Some emergence occurred with species from seed up to 10 years old.
Documenting the successful interspecific crosses in a genus is a valuable tool in making decisions in developing strategies for plant breeding activities. However, summarizing the breeding and hybridization can be confusing because of incomplete or lost breeding records and the failure to register the parentage of new cultivar names. A summary of interspecific crosses in the genus Penstemon at the University of Nebraska–Lincoln West Central Research and Extension Center over 10 years provides insight into both successful and unsuccessful crosses. The results, based on seed production and percent of successful crosses, would suggest that interspecific crosses are more likely to be successful when the parent species are more closely related.
Two studies in west-central Nebraska to determine the survival of wildflowers planted with buffalo grass [Buchloe dactyloides (Nutt.) Engelm.] and blue grama grass [Bouteloua gracilis (H.B.K.) Lag. ex Steud.)] were conducted in 6 and 10 year studies. In total, 19 forbs and 1 grass were transplanted with `Texoka' buffalo grass in the first study, and 16 forbs were planted in a split-plot design into 3 buffalo grass selections, blue grama or a clean cultivated plot in the second study. Survival between transplants in both studies varied significantly. In the first study, survival was significantly higher for little bluestem (Schizachyrium scoparium Michx.) (85%), bouncing bet (Saponaria officinalis L.) (100%), and stiff goldenrod (Solidago rigida L.) (100%) over the 6 years of the study. In the second study, there were significant differences between species for survival, with grayhead prairie coneflower [Ratibida pinnata (Vent.) Barnh.] (85%) and pitcher sage (Salvia azurea Lam.) (80%) having the highest survival at the end of the 10-year study. There were significant differences in height and number of flower stalks within S. rigida, R. pinnata, and S. azurea between years and between main plots. This study demonstrates differences in survival and growth of wildflowers when planted in conjunction with buffalo grass and blue grama grass.
Severity of rust (Uromyces appendiculatus) and yield of dry edible beans (Phaseolus vulgaris L.) were recorded for 9 years in west-central Nebraska in fungicidal efficacy trials. A weighted analysis of covariance was used to estimate yield loss due to rust. The model fit the data well (R2=0.94), and the slope over all years had a 19 kg.ha−1 decrease in yield for each 1% increase in severity of rust. Yield response within years occurred only through reduction of rust for most fungicide treatments.