Genetic purity testing of 'Catigan Green Dwarf' (CATD) coconut parental palms using SSR DNA markers

Issue Date

6-2017

Abstract

>Unlike tall coconut varieties, dwarf coconut varieties are generally homozygous purelines which makes them useful in coconut breeding and generating mapping populations 'Catigan Green Dwarf' (CATD) is a local coconut variety known for its high nut yield compared to other varieties. CATD parental palms were used as female parent in generating the mapping population CATD x (LAGT x WAT). However, despite dwarf coconut varieties' predisposition towards homozygesity, levels of outcrossing may still be observed due to natural cross pollination among adjacent palms. To assess the genetic purity of palms used in the crosses, genomic DNA was extracted from the leaves of 38 CATD parental palms, which were then screened for heterozygosity using 45 SSR DNA markers evenly distributed in the coconut genome. Polymerase chain reaction (PCR) amplification was performed followed by 8% polyacrylamide gel electrophoresis (PAGE) to visualize amplicons. The genotypic data was recorded for each palm and SSR marker to determine the level of heterozygosity. Four CATD parental palms were identified to be 100% heterozygous, and 15 parental lines were highly homozygous with heterozygosity at 1-3 loci, while two are highly heterozygous exhibiting heterozygosity at 5 loci or more. The lowest heterozygosity was observed in CATD 2116 and CATD 1617 at 88.9% and 86.7%, respectively. Heterozygosity observed in selected CATD palm is uncommon among dwarf coconut varieties. Results of this study could provide insights in selecting the individual coconut palms among the segregating population to genotype as well as the identification of the material alleles.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463X

Volume

42

Issue

Supplement no. 1

Page

105

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Language

English

Subject

Coconut -- Varieties; Plant breeding

En – AGROVOC descriptors

COCOS NUCIFERA; VARIETIES; DNA; GENETIC MARKERS; GENOTYPES

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