Chemical and agronomic evaluation of common milkweed,Asclepias syriaca

Abstract

Common milkweed (Asclepias syriaca) has been identified as a potential whole-plant source of poly phenol, oil, and polymeric hydrocarbon. Based on in situ sampling, a range of 4.7-14.4% (dry weight) polyphenol + oil (variation significant at 1% level) and 0.2-1.2% polymeric hydrocarbon (variation significant at 5% level) were found among 48 Maryland and northern Virginia populations. In a 2-yr replicated evaluation of progenies from 41 populations, significant differences (5% level) in vigor,Aphis nerii feeding preference, numbers of plants surviving the seeding year, and numbers of tillers produced the second year were observed. Genetic variation for agronomic traits was generally small, but appeared sufficient to justify a breeding program. Excluding aphid feeding-preference, all agronomic variables were positively correlated with each other (significant at 1% level); aphid feeding-preference was weakly, negatively correlated with the remaining agronomic variables (significant at 1% level). Chemical and agronomic data were not significantly correlated. Factor analysis indicated that plants which performed well early in their life cycle would be expected to perform well on a long term basis. Based on cluster analysis, the environment in which some populations developed may have affected in situ production of poly phenols + oil and polymeric hydrocarbon as well as the subsequent agronomic performance of their progenies.