COLLECTING WILD SUNFLOWER GERMPLASM FROM THE CENTRAL GREAT PLAINS OF U.S.A.

Abstract

One hundred forty-four accessions representing eight wild
species of sunflower were collected from 124 sites in diverse
habitats of the Central Great Plains of United States of America
during September, 1991. A wide range ofin-situ variability was
observed for various morphological and economic characters
including stress tolerance. The populations of H. annuus were
observed to be highly variable and widely distributed in different
habitats in the seven states surveyed. Helianthus pumilus which
has low variability and limited distribution, was represented by
only one sample in Colorado. Helianthus petiolaris ssp.
petiolaris, the only source species of cytoplasmic male sterility
was found, widely distributed and along sandy roadsides of
highways. Helianthus pauciflorus ssp. subrhomboideus