"Validation of salinity tolerance QTL-linked SSR markers in chromosomes 2, 3, 4, 6, 9 and 12 in selected salt tolerant geno - types of rice (Oryza sativa L.)"

Date

4-2011

Degree

Bachelor of Science in Biology

Major Course

Major in Ecology Genetics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Neilyn O. Villa

Co-adviser

Glenn B. Gregorio

Abstract

Salinity tolerance of 314 lines of rice (Oryza saliva L.), including three checks (FL478, IR64 and 1R29) and five FL lines, which were grown in a hydroponic system using the Yoshida culture solution, was evaluated using the modified standard evaluation score. One percent was found to be highly tolerant to salinity, 10% were tolerant, 29% were moderately tolerant, 34% were sensitive and 26% were highly sensitive. This demonstrates the susceptibility of rice to salinity at seedling stage. Thirty seven genotypes of rice were selected for further genetic analysis using nine SSR markers. The 37 genotypes were selected because they would most probably contain the gene responsible for salt tolerance. Results show that the number of alleles present ranges from 3 to 6, while the PIC value ranges from 0.41 to 0.79. A high association between gene . diversity and PIC value was observed. Cluster analysis based on the SSR markers used divided the 37 genotypes into roughly two groups. However, because of the limited set of SSR markers, a well-represented dendrogram that groups the different genotypes based on their genetic relatedness was not obtained. Moreoever, haplotype analysis revealed a total of 30 haplotypes in reference to Pokkali. None of the 36 genotypes had a similar haplotype with Pokkali, meaning none of the other genotypes possess all the SSR markers present in Pokkali. However, the absence of the alleles from the other genotypes does not necessarily signify their susceptibility to salinity. Rather, their tolerance may be attributed to chromosome 1, from other QTLs found in any of the 12 rice chromosomes, or the genotype has a novel QTL that confers salinity tolerance via another mechanism different from that of Pokkali.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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