Evaluation location: Illinois, United States
One hundred seventy-six seeds per accession were planted in individual Jiffy pellets (Hummert Seed Company, Earth City, Mo) in August 2000 and 2001. They germinated in flats in the greenhouse. Four weeks after planting, the V. villosa plant material was transplanted to field plots in Urbana, IL. The V. pannonica plant material was transplanted to field plots 6 wk after planting in the greenhouse. The field design was a randomized complete block with two blocks. In each block, there were 44 plots measuring 2 by 1 m. Each plot represented an individual accession, and there were 50 plants transplanted to each plot. The individual plants were planted in a five columns by 10 rows lattice with 200 mm between each plant. This was conducted in 2 yr. Initial seed weight for 100 seeds per accession was measured. Percentage germination was calculated for each accession on the basis of the number of plants germinated/total seeds planted in the jiffy pellets. Stem length, stem width, leaf length, and leaf width were measured with a caliper to record fall growth in late October. These measurements were taken on five random plants per accession plot. The leaf measurements were taken near the base of the plant on the third leaflet from the tendril. Stem measurements were taken on the main stems. Ten leaf and stem measurements were taken from each plant. In late April 2001 and April 2002, several additional measurements were recorded in the field for each accession. Winter survival percentages for each accession were determined by number of plants alive/number of plants transplanted. Five plants per plot (if not winter-killed) were randomly selected to measure stem length, stem width, leaf length, and leaf width, with the same methods as the fall measurements. Additionally, a random (30 by 60 cm) section of each plot was cut with hand clippers and weighed for biomass accumulation. Standing residues were cut at ground level with electric shears and the plant material was gathered by hand. Residue samples were dried for 3 d at 65?C, weighed, and ground to pass through a 1-mm mesh. Residue samples were analyzed for total C and N with an automated Dumas instrument (Leco CHN-2000. Leco Corp., St. Joseph, MI). These data were included in the statistical analysis as a ratio of C to N (C:N ratio).
For an Excel file of the 2000 and 2001 data.