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https://hdl.handle.net/2142/21515
Description
Title
Flow cytometric analysis of the maize genome
Author(s)
Biradar, Digambareppa Pandappa
Issue Date
1993
Doctoral Committee Chair(s)
Bullock, Donald G.
Department of Study
Crop Sciences
Discipline
Crop Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture, Agronomy
Biology, Genetics
Language
eng
Abstract
Studies on analysis of the maize genome using flow cytometry were carried out at the University of Illinois, Urbana-Champaign. These studies were performed in order to gain a better understanding of the maize genome, its effect on plant performance and factors which could disrupt it.
In the first two studies, the nuclear DNA content of several F1 hybrids was analyzed using the fluorochrome DAPI (4$\sp\prime$-6-diamidino-2-phenylindole). Five hybrids were observed to have had significantly higher nuclear DNA content than their respective parental means. In hybrids that had a low heterotic response, the observed nuclear DNA content exceeded the expected DNA amount. The unstable inheritance of DNA in these hybrids suggests a relationship between heterosis (an agronomic trait) and nuclear DNA content.
In the third, fourth and fifth studies, intraplant variation in nuclear DNA content was investigated. Significant differences were observed with respect to nuclei distribution in the higher ploidy peaks of diploid and tetraploid maize tissues. Variation in the degree of endopolyploidy observed in maize appeared to have an effect on overall agronomic performance under field conditions. Intraplant variations with respect to DNA content in maize diploid nuclei were observed as well. Nuclei from meristematic root and stem had similar amounts of DNA. Nuclei from differentiated mesocotyl and nodal root had lower amounts of DNA. Propidium iodide (PI) in conjunction with DAPI was used for probing chromatin structure in maize diploid nuclei isolated from meristematic and differentiating tissues. Nuclei from various tissues were found to have different chromatin structure.
In the sixth study, nuclear alterations were observed in seedlings grown from kernels treated with benzimidazole RP-727 fungicide. The magnitude of alterations were minute. The alterations were found to be different in various plant organs analyzed. The results indicated that agrichemicals can potentially alter the genome organization of plant nuclei.
In the last study, agronomically important growth and yield parameters showed negative correlations with nuclear DNA amount in maize. These correlations demonstrate how the nucleotype may exhibit a high degree of influence on the agronomic phenotype.
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