Natural Populations of Hesperaloe (Agavaceae) in Texas

Species of colletotrichum on agavaceae.

Species of Colletotrichum cause diseases on a wide range of hosts, frequently infecting plants in the Agavaceae (monocotyledons: Liliales). Three species of Colletotrichum restricted to the Agavaceae were detected through morphological studies of specimens and molecular sequence analyses of the LSU of the nu-rDNA and the ITS region of the nu-rDNA from cultures. Colletotrichum agaves on Agave is...

Essential oil variations among the natural populations of Francoeuria undulata

Francoeuria undulata (L.) LACK is often synonymous with two species of the genus Pulicaria,i.e. Pulicaria undulata (L.) C.A. Mey and Pulicaria crispa (Forssk.) olive, which are oftenincluded under the genus Francoeuria. The essential oil yield and compositions in the fivenatural populations of Francoeuria undulata from Fars Province in southern Iran weredetermined by GC and GC/MS analysis. The ...

The Natural Variation in Six Populations of Calendula officinalis L.: A Karyotype Study

In the current investigation, karyotype analysis and chromosome characteristics of six populations of Calendula officinalis L.(pot marigold) from Iran are studied. Results showed that all populations were diploid (2n= 2x= 32), and had symmetrical karyotypes composing mainly of metacentric and submetacentric chromosomes. The mean chromosome length ranged from 1.05 in Karaj to 1.50 μm in...

Genetic variation in natural populations

Genic Variation in Natural Populations

By characterizing the struggle to measure variation as a struggle between two opposing views, the classical and balance theories of population genetics, I have in part obscured the underlying problem of making a functional whole out of theory and observation. Suppose that the experiments of Wallace and of Mukai had proved beyond any reasonable doubt that new mutations were, on the average, hete...