Document Type

Thesis - Open Access

Award Date

1981

Degree Name

Master of Science (MS)

Department

Biology

Abstract

Chromosome and genetic instabilities were reported in many plant species (c.f. Partanen, 1963; Sunderland, 1973; Skirvin, 1978; D'Amato, 1976; 1978). D'Amato (1976) suggested that, in higher plants, only meristematic cells were genetically stable; explants excised from stem apices would then ensure genetic uniformity for in vitro plant propagation. However, cultures derived from shoot apices were generally inefficient for vegetative propagation. The usefulness of a tissue culture technique for cloning would then be judged not only by the degree of genetic variation in the tissue culture-derived population, but also by the amount of plantlets initiated from a culture. In this laboratory, rapid cloning through tissue culture has been achieved in many forage grass species using young inflorescenes as explants (Chen et al., 1977; 1979; Lo et al., 1980). Genetic uniformity in these tissue culture-derived grass populations are being studied morphologically and cytologically. In a callus culture derived big bluestem plant populations, Chen et al. (1981) reported the existence of small portions of autotetraploids which were primarily identified by their gigantic characters, including pollen size. The ploidy of these plants was later identified by meiotic chromosome counts. However, in the culture derivatives of Indiangrass (Sorghastrum nutans L. Nash), no apparent morphological differences were found. This species was believed to be an allotetraploid with a chromosome number of 2n = 4x = 40 (Gould, 1956). Thus, some effects of chromosome aberrations, if present, might be masked by their homoeologous counterparts so that manifestation of the aberrations would not be detected morphologically. This thesis deals with meiotic studies of two plant populations derived from callus cultures of two genotypes of Indiangrass.

Library of Congress Subject Headings

GrassesMeiosis
Forage plants

Format

application/pdf

Number of Pages

54

Publisher

South Dakota State University

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