Cytogenetics analysis of seed callus culture-derived R1 lines of rice (Oryza sativa, L.) cultivar momay

Date

4-1993

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Edwin L. Javier

Abstract

The explant source Momay and fourteen seed callus culture-derived R. lines, representing tillers from five regenerants, and their source plant Momay were cytologically analyzed. Normal chromosome numbers (2n=24) were prevalent. In Mossy, one cell (1.75%) had 25 chromosomes. This aberrant meiotic cell could have originated from a somatic cell with the same number. Somatic mutation like non-disjunction of sister chromatids can occur spontaneously. Variation in chromosome number (22-28) was found in 10 R. lines with a frequency as high as 21.43% (line 499-1). Chromosomal instability could have been induced during callus culture and carried over from the R. to the R. generation. Analyses of chromosome behavior at diakinesis, metaphase 1, anaphase 1 and telophase 1 were also done. At diakinesis, various chromosome configurations were noted. Bivalent associations, indicating some degree of homology between the chromosomes involved, were also observed. Relatively high frequencies of non-congressed chromosomes, particularly bivalents were observed at metaphase 1. However, these apparently caught up at the metaphase plate since high frequencies of normal cells were observed at anaphase 1 and telophase 1. The chromosome number aberrations indicate the mutagenic property of the tissue culture process. Variations between regenerants are indicative of variations in the groups of callus cells which gave rise to different regenerants. Variations among lines from one regenerant, indicate variation in cells of a given callus that gives rise to a regenerant.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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