Identification of Genetic Relationship in Taiwan Avocado Cultivars by Leaf Volatile Constituent Analysis and SSR Markers
Date Issued
2008
Date
2008
Author(s)
Wu, Hsiang-Lin
Abstract
Forty-five avocado species were selected from three pure races, known hybrid races and Taiwan cultivars in Taiwan, El Salvador and United States. Fifty-two leaf samples were used in volatile constituent tests, and sixty-five DNA samples were used in simple sequence repeat tests. Taiwan avocado leaf samples were collected from Chiayi Agricultural Experimental Station (CAES) and Shen’s orchard. Import leaf samples were supplied by Germplasm Reserves of Institute of Agricultural Experiments in El Salvador. Eleven DNA samples of pure West Indian race were provided by University of California, Riverside. In comparison with headspace-gas tight syringe direct injection, solvent extraction, pyrolyzer, headspace-solid phase microextraction were selected for sample preparation. GC-MS were used as the analyzing instrument. Twelve race-specific compounds and ten magnitude-varied characteristic compounds were selected as the indicators for further analysis. Similarity matrix of volatile constituents was calculated by Euclidean distance of base-10 logarithm value of indicator compounds calibrated abundance, and dendrogram was clustered based on unweighted pair group method arithmetic average (UPGMA). Similarity matrix was calculated by Jaccard index using 14 primers generated 81 polymorphic fragments. Three avocado pure race samples were separated into three major groups on the dendrogram of volatile constituents test results. Taiwan cultivar and pure West Indian race samples were clustered in the same group on volatile constituent dendrogram. On the dendrogram of simple sequence repeat test results, all test samples were divided into four major groups, Mexican, Guatemalan,.West Indian race related speciess, and Taiwan cultivars, repectively. Genetic distance of the Taiwan cultivar samples were closed to West Indian samples on the dendrogram of simple sequence repeat testing results. With the benefits of easy operation, fast analysis, good repeatability and reproducibility, volatile constituent analysis of avocado leaves could be used as a morphological taxonomy method. Calibrated abundance by internal standards of testing data of GC-MS could be merged into database, and generated a new dendrogram with the all data in the database. Experimental results proved that this is a feasible method for genetic relationship identification.
Subjects
avocado
volatile constituent
simple sequence repeat
headspace-solid phase microextraction (HS-SPME)
gas chromatography- mass spectrometry (GC-MS)
chemotaxonomy
Type
thesis
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