Document Type

Thesis - Open Access

Award Date

1956

Degree Name

Master of Science (MS)

Department / School

Agronomy

Abstract

Colchicine-treated seedlings of a true-breeding variety of Sorghum vulgare Pers. were found to differ in appearance from the untreated checks while retaining the original chromosome number (1,8). Some of the mutant plants bred true for the changed characters in succeeding generations. Cytological examination by Harpstead et al (2) showed no abnormal pairing relationships or detectable chromosomal abnormality in the meiotic stages of the treated material, the untreated material, or their F1 crosses. From these findings it was postulated that colchicine caused a somatic reduction of the chromosomes together with concurrent mutagenic effects and subsequent restoration to the diploid number. A cell thus formed might, because of chance genotypic or positional advantage, take over the growing point and form homozygous tissue of a different genotype from the original embryo. To determine whether the mutations were limited to one part of one chromosome, or if they might be scattered randomly throughout several chromosomes, several populations from crosses of colchicine-induced mutants of unknown genotypic constitution and their untreated full sibs were studied during the summer of 1954. The seed for this study was obtained from the F1 plants previously studied by Harpstead et al (2).

Library of Congress Subject Headings

Sorghum
Colchicine
Cytogenetics

Description

Includes bibliographical references (page 42)

Format

application/pdf

Number of Pages

51

Publisher

South Dakota State University

Rights

No Copyright - Non-Commercial Use Only
http://rightsstatements.org/vocab/NoC-NC/1.0/

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