Morphological Characterizations, Genetic Diversity and Population Structure of Date Palms (Phoenix Dactylifera L.) in Ethiopia
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Date
2024-10
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Addis Ababa University
Abstract
Date palm tree is aperennial plant that belongs to Arecaceae family and it significantly contributes to agricultural sustainability and socio-economic values for many countries including Ethiopia. Scientific evidences from molecular and morphological genetic data of date palms are the baseline for establishment of gene banks, conservation and to develop breeding programs. In Ethiopia, there is lack of genetic information about date palm trees. Therefore, the objective of this dissertation is to evauate the genetic diversity and population structure of date palms in Ethiopia. In this study, 45 morphological traits for 11 individual date palms, 10 Inter Simple Sequence Repeat (ISSR) markers for 113 date palm genotypes, 10 Simple Sequence Repeat (SSR) markers for 124 date palm genotypes and 4 Single Nucleotide Polymorphism (SNPs) markers for 15 date palm genortypes were used.
The morphological diversity analysis was based on principal component analysis using the total 45 traits showed 37% variations exist among 11 individuals. The morphological data analysis using 25 vegetative traits alone as well as the data from 20 reproductive traits alone 29% and 32% of variations was observed respectively. Fourty three morphological traits exhibited significant differences at p < 0.05 in analysis of variance and 23 traits showed significant variances at p < 0.05 in homogeneity of variance analysis among cultivars. Dendrograms indicated clear genetic relationships of cultivars. From ISSR analysis, a total of 241 DNA fragments were generated by all primers and each primer showed 100% of polymorphism. The highest (37) and the lowest (10) number of bands were produced by (AGG)6 and (AG)10C primers, respectively. AMOVA result showed 49% and 51% within and among population diversity, respectively, and also, the first three PCoA accounted for 10.55%, 9.17% and 7.68% variations. The genotyes were also clustered according to their geographical location. From SSR analysis: a total of 112 of alleles were detected, Neighbour-joining clustering analysis based on dissimilarity coefficient values the date palm popuatons grouped into five major categories. Population structure analysis at the highest K value grouped the genotypes into three groups. Principal coordinate analysis explained a total variation of 17.33%. The discriminant analyses of principal components also separated date palm genotypes into eight clusters. From SNPs data, genetic variations were shown in phylogenetic tree, nucleotide content and pairwise distance analysis of date palm genotypes. Generally, evaluation of genetic diversity and phylogenetic structure of date palms using molecular and morphological markers is very important. The overall findings of this study are helpfull to design genetic improvement, conservation and germplasm introduction programs of date palms in Ethiopia and elsewhere.
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Keywords
AMOVA, Date Palm, Genetic Diversity, ISSR, SNPs and SSR Markers, Morphological Traits, Polymorphism, Population Structure, Genetic Diversity