Analysis of genotypic variability of Mycosphaerella fijiensis, the causal pathogen of black sigatoka of banana, in Bukidnon and Davao, Philippines

Date

7-2015

Degree

Bachelor of Science in Agricultural Biotechnology

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Edna Y. Ardales

Abstract

Microsatellite and variable number tandem repeat (VNTR) markers were used to analyze the genetic variability of Mycosphaerella fijiensis, the casual pathogen of black Sigatoka of banana. These markers were preselected based on their capacity to generate polymorphism and their dispersal across the genome of M. fijiensis. A total number of confirmed 168 M. fijiensis isolates were analyzed for population structure according to subpopulations of provinces, collection sites and varietal origins. Composite band (or haplotype) data, with respect to the microsatellite and VNTR markers, were used to analyze the genetic diversity and differentiation of the different subpopulations. The mean PIC value of the ten microsatellite and three VNTR markers was 0.49. The gene diversity obtained from the entire population was 0.53, a value that is relatively higher compared to the gene diversity observed in other geographic locations outside the Philippines. The gene diversity values within provinces ranged from 0.40-0.57. On the other hand, the gene diversity values within varieties in Davao and Bukidnon ranged from 0.49-0.54. High genetic diversity was expected in Bukidnon and Davao because these provinces are part of the center of origin of the disease which is Southeast Asia. Within collection sites diversity of the 15 collection sites in Davao and Bukidnon ranged from 0.24 to 0.53. The subpopulations from Davao City and Bukidnon were found to be genetically close to each other with a pair-wise Fѕт value of 0.041. On the other hand, the highest genetic differentiation observed was between the subpopulations in Davao del Norte, where isolates were mostly collected from leaf samples from banana plantations, and Davao del Sur, where isolates were collected from banana plants planted along the highway ( Fѕт = 0.14). Through Neighbor-Joining method, three groups were formed across the 168 M. fijiensis isolates based on genetic distances among the isolates. There was no correlation found between the genetic distance and geographic distance of the subpopulations. The genetic distance of the 168 M. fijiensis isolates was also found not to be influenced by varietal origin.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2015 A127 /C84

Notes

Major in Crop Protection Biotechnology

Document Type

Thesis

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