CHLOROPLAST AND NUCLEAR-DNA VARIATION AMONG HOMOZYGOUS PLANTS IN A POPULATION OF THE AUTOGAMOUS ANNUAL MICROSERIS-DOUGLASII (ASTERACEAE, LACTUCEAE)

The autogamous diploid annual Microseris douglasii of California occur s in many isolated populations. The populations consist of one to many highly inbred biotypes. Morphological variation among populations usu ally is greater than within populations. In spite of the virtual absen ce of gene flow even within populations, genetically determined charac ter differences are randomly distributed and associated throughout the range of the species. Recent evidence even suggests introgression of chloroplasts from the related M. bigelovii. Offspring families from 25 plants of a very variable population were raised and examined for seg regation of morphological and molecular (RAPD) markers. All 25 origina l plants were completely homozygous for all markers, but each differed from all others at least in some markers. The population consisted of two genetically isolated groups of plants: a distinct inbred line (3 plants) and 22 plants with random associations of a common set of mark ers and characters, possibly recombinant inbreds from a past hybridiza tion event. One of these 22 plants contained a chloroplast genome foun d in M. bigelovii, the other 24 plants a chloroplast genome found only in M. douglasii.