ISOZYME AND RAPD VARIATION AMONG AND WITHIN HEMP DOGBANE (APOCYNUM-CANNABINUM) POPULATIONS

Clonal individuals from IG hemp dogbane populations with phenotypic va riation were analyzed using isozyme and randomly amplified polymorphic DNA (RATD) analysis. Plants originated From populations in Michigan a nd Illinois. Three known Apocynum species, spreading dogbane, hemp dog bane, and prairie dogbane, were evaluated. Genetic distance among popu lations was more pronounced with isozyme analysis compared to RAPD ana lysis. The combined isozyme and RAPD analysis data separated spreading dogbane from all other plants analyzed. Genetic variation was present among the 16 hemp dogbane populations, but was less than expected bas ed on the phenotypic variation present among the collections. The shor t genetic distance between the 16 hemp dogbane collections and the thr ee Apocynum species suggests that variation among populations of hemp dogbane may be from outcrossing with other closely related Apocynum sp ecies. Isozyme and RAPD analyses were also conducted on plants from tw o populations in Michigan to determine the level of genetic variation among plants within the same population. Genetic analysis revealed tha t one population was entirely clonal, while the other population was a mixture of clonal and segregating plants.