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Cornus kousa Hance (Korean or kousa dogwood) cultivars are increasingly used as landscape plants because they lack the disease and insect problems typically associated with the native C. florida L. (flowering dogwood). A number of red-bracted kousa dogwood cultivars are now available and several are phenotypically indistinguishable from one another. Plants of six cultivars obtained from three nurseries were characterized genetically using deoxyribonucleic acid (DNA) amplification fingerprinting (DAF) and arbitrary signatures from amplification profiles (ASAP). DAF profiles of three red-bracted cultivars—`Rosabella', `Satomi' and `Heart Throb'—were nearly identical. ASAP also failed to clearly differentiate these cultivars and indicated consistent genetic similarities. In contrast, another red-bracted cultivar `Christian Prince' and two white-bracted cultivars—`Little Beauty' and `Samaritan'—were identified and separated from all other cultivars by both DAF and ASAP techniques.

One of the most frequently used tools in plant biotechnology, which includes genomics and proteomics, is gel electrophoresis. Our experience with middle and high school students as well as teachers and undergraduate students is that they have very little, if any, hands-on experience with this technique. These exercises were developed to demonstrate the principles of electrophoresis and DNA fingerprinting in middle and high school and university laboratories with minimal expense and equipment. The experiments have been tested by middle and high school students, as well as by teachers, and undergraduate and graduate students. The first exercise, electrophoresis of common food dyes, is primarily designed for secondary and undergraduate students, but can be used as an inexpensive means for introducing the main concepts of electrophoresis to anyone who has little or no experience, including graduate students. Popular brands of food dyes (red, blue, yellow, and green) purchased at local markets are mixed into a 60% glycerol/water solution and are separated on 1% agarose gels using 100 V for 35 min. Mixed colors are separated into primary colors (e.g., green into blue and yellow) and some apparently single dyes often have extra “surprise” components. A simple exercise illustrating forensic use of gel electrophoresis with dyes is also included. Over 100 students and teachers have completed this experiment successfully. The second laboratory exercise requires more extensive equipment and a more advanced set of skills; however, the exercise has been completed successfully by middle school-level through graduate-level students and by teachers. In this exercise, the internally transcribed spacer region of the ribosomal subunit for a fungus, plant, and insect are amplified and separated electrophoretically on agarose gels. A simple crime is solved using polymerase chain reaction (PCR) and DNA fingerprinting. The experiment protocol provides students with hands-on activities that include assembling master mixes for PCR, practice using pipettes, and performing the various steps involved in PCR amplification. Instructions for both exercises are formatted in easy-to-follow procedure boxes, and a downloadable presentation is available on the web. The cost of the expendables is about $1 per student, making these exercises relatively inexpensive to conduct, assuming that hardware and DNA are available.

Helianthus verticillatus Small (whorled sunflower) is a federally endangered plant species found only in the southeastern United States that has potential horticultural value. Evidence suggests that H. verticillatus is self-incompatible and reliant on insect pollination for seed production. However, the identity of probable pollinators is unknown. Floral visitors were collected and identified during Sept. 2017 and Sept. 2018. Thirty-six species of visitors, including 25 hymenopterans, 7 dipterans, 2 lepidopterans, and 2 other insect species, were captured during 7 collection days at a site in Georgia (1 day) and 2 locations in Tennessee (6 days). Within a collection day (0745–1815 hr), there were either five or six discrete half-hour collection periods when insects were captured. Insect visitor activity peaked during the 1145–1215 and 1345–1415 hr periods, and activity was least during the 0745–0845 and 0945–1015 hr periods at all three locations. Visitors were identified by genus and/or species with morphological keys and sequences of the cox-1 mitochondrial gene. The most frequent visitors at all sites were Bombus spp. (bumblebees); Ceratina calcarata (a small carpenter bee species) and members of the halictid bee tribe Augochlorini were the second and third most common visitors at the two Tennessee locations. Helianthus pollen on visitors was identified by microscopic observations and via direct polymerase chain reaction of DNA using Helianthus-specific microsatellites primers. Pollen grains were collected from the most frequent visitors and Apis mellifera (honeybee) and counted using a hemocytometer. Based on the frequency of the insects collected across the three sites and on the mean number of pollen grains carried on the body of the insects, Bombus spp., Halictus ligatus (sweat bee), Agapostemon spp., and Lasioglossum/Dialictus spp., collectively, are the most probable primary pollinators of H. verticillatus.