Genetic diversity analysis of three Oryza nivara Sharma et Shastry accessions across multiplication cycles using flourescent-labeled Simple Sequence Repeats (SSR) markers

Date

5-2008

Degree

Bachelor of Science in Biology

Major Course

Major in Cell Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Adelina A. Barrion

Abstract

LISTANCO, OLIVIA FAYE JAZMIN, University of the Philippines- Los Banos, Laguna, 2008. Genetic Diversity Analysis of Three Oryza nivara Sharma et Shastry Accessions Across Multiplication Cycles Using Fluorescent-labeled Simple Sequence Repeats (SSR) Markers

Adviser: Dr. Adelina Barrion Co-adviser: Dr. Kenneth McNally

The amount of genetic diversity in three Oryza nivara accessions namely; IRGC 92744, IRGC 92883, and IRGC 93928, to determine the consequences of repeated multiplication of seeds, and to assess germplasm conservation and management. Genetic diversity was estimated in 223 O. nivara samples belonging to three accessions represented by the Original samples (OS) and multiplication seasons, 2000 wet season and 2005 wet season, seeds using fluorescent-labeled SSR markers. Twelve SSR primers detected varying numbers of alleles ranging from 5 to 21 with the average of 17.33 alleles per primer. Clustering of the samples based on their multiplication seasons within an accession suggested changes in genetic composition. In IRGC 92744, an increased in levels genetic diversity was observed within the population. This was implicated by increased number of observed and effective number of alleles, heterozygosity, and Shannon-Weiner index as the seeds underwent multiplication events. In IRGC 92883 and 1RGC 93024, a decreasing trend in the parameters suggested a decline in genetic diversity within the accession through the multiplication events. An increase in the genetic composition of core collections can change during storage and multiplication events. In the multiplication events, contaminations and mislabeling of seeds can also introduce new alleles, thus altering the genetic composition of the population. The decrease in the genetic diversity of germplasm accessions can be due to favoring of certain allele or allelic combinations as affected by the viability of the seeds. Robust seeds are mostly likely to be multiplied, amplifying their certain alleles and eliminating others. This is reflected with increase in allele frequency through regeneration seasons. The drift of certain alleles causes the decrease in genetic composition of a population. The conservation of wild rice diversity in germplasm collections has provided valuable resources for plant breeding. It has played an important role in providing alternative sources of genes for rice improvement programs. The dynamic changes in genetic compositions of germplasm collections merit diversity analysis studies. In depth appreciation in genetic diversity in gene banks will facilitate the classification, proper maintenance, conservation, and utilization of its collection. Studies in the behavior of genetic composition in cultivated and other wild species of rice maintained in gene banks should also be done, since not all Oryza species are exclusively inbreeding. The use of other markers and techniques in assessing diversity within germplasm accessions should be done.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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