Date of Publication

7-2025

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Biology

Subject Categories

Biology

College

College of Science

Department/Unit

Biology

Thesis Advisor

Ma. Carmen A. Lagman

Defense Panel Chair

Mark Christian Felipe R. Redillas

Defense Panel Member

Yokimiko D. Torrejos
Raymond Vincent F. Castillo

Abstract (English)

Brown planthopper (BPH) and green leafhopper (GLH) are major insect pests affecting rice production in the Philippines, with GLH acting as the primary vector of the tungro virus. While molecular studies on BPH resistance have led to the identification of resistance genes and associated markers, limited molecular insight into GLH resistance remains. This study explores whether Bph1-linked microsatellite (SSR) markers can also serve as potential indicators of GLH resistance in selected Philippine rice varieties. By integrating phenotypic resistance data from the publicly available Pinoy Rice Knowledge Bank (PRKB) by the Philippine Rice Research Institute (PhilRice) with existing microsatellite markers, this study aimed to investigate whether Bph1 allele configurations could be correlated with resistance to GLH in local rice varieties grown under irrigated and rainfed rice ecosystems. A matrix-style analysis table was created, in which a total of 297 local rice varieties were screened using resistance classification data. From the subset of rice varieties cultivated under irrigated and rainfed environments, the screening results provide preliminary evidence of a possible association between BPH and GLH resistance and a 43.2% likelihood that resistance to BPH may co-occur with resistance to GLH. Selected rice varieties with different resistance profiles were analyzed through gel electrophoresis and compared against their phenotypic classifications. Results showed that varieties with similar resistance phenotypes did not consistently share common allele patterns. Notably, heterozygous Bph1 alleles were found in both dually resistant (+ +) and dually susceptible (− −) varieties, suggesting that Bph1 alone is not a reliable indicator of GLH resistance. These inconsistencies indicate that other genetic loci may be responsible for GLH resistance. Further studies involving additional BPH resistance genes, larger sample sizes, and gene expression analysis are recommended to better understand the genetic basis of multi-pest resistance in Philippine rice varieties.

Abstract Format

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Abstract (Filipino)

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Abstract Format

html

Language

English

Format

Electronic

Keywords

Rice--Philippines; Leafhoppers; Microsatellites (Genetics); Pinoy Rice Knowledge Bank

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Embargo Period

8-7-2025

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