MORPHOLOGICAL VARIATION AMONG HEMP DOGBANE (APOCYNUM-CANNABINUM) POPULATIONS

Experiments were conducted to examine morphological variation among he mp dog-bane populations. Rootstocks collected from 16 sires throughout Michigan and Illinois were used to establish nurseries in East Lansin g, MI, and Champaign, IL. Growth, stem characteristics, and leaf chara cteristics were measured for each ecotype at both nurseries. Differenc es among ecotypes were observed for all measurements except emergence date and growing degree days to emergence. The number of shoots per pl ot produced by the ecotypes ranged from 5 to 54 and shoot height range d from 69 to 126 cm. Ecotypes spread laterally at different rates, wit h the most aggressive covering 19 rimes more ground area than the leas t aggressive. Total shoot dry weight accumulation varied greatly among ecotypes. Some ecotypes could be identified from others by their uniq ue leaf shape. Shoot number, shoot height, and ground area covered wer e greater for plants grown in Michigan than in Illinois. Differences i n growth and morphological characteristics among ecotypes were not cor related with the geographical region where they were collected. Differ ences in measurements between the two nurseries illustrate the role of environment and genetics in the growth and morphology of this plant s pecies.