Diversity Assessment and Cultivar Identification in Date Palm through Molecular Markers- A Review

Abstract

Date palm has a long history of cultivation and a valuable germplasm with little knowledge about its genetic makeup and variation among the most cultivated cultivars. Diversity is the variability of a species. Plants show variation in yield, vegetative traits and morphological properties of fruits and seeds in response to environmental changes. Molecular markers or DNA markers have been in use since past three decades. The DNA profiles give information about the genotype, screen the whole genome and show variation in both the coding and noncoding region and hence give information about polymorphism. Since plastid genes are transferred mostly from the mother line, the identification of maternal lines is possible by the sequencing of plastid genes. Simple sequence repeats (SSRs) can detect length variation with the help of Polymerase Chain Reaction (PCR) and may be used as highly informative genetic markers. Single Nucleotide Polymorphism (SNPs) are the third generation of molecular markers. SNPs are more stable and have high fidelity of inheritance as compared to other marker systems. Molecular markers have been developed but they are not enough for sufficient diversity assessment. Therefore there is a need to increase the number of DNA markers in date palm. Previously, there are several studies to type various commercially important germplasm based on morphological or yield parameters. Morphological and biochemical markers are limited in number and are affected by environmental factors and growth stage of the plant which reduce their reliability in the assessment of diversity and characterization of the germplasm. This necessitates the use of genetic characterization, utilizing DNA markers, gene sequencing or SNP genotyping which can work independent of the plant growth stage and are not affected by environmental factors. A combination of morphological, biochemical and molecular characterization of the date palm cultivars can better assess the level of diversity and relationship among the cultivars.

Whole Genome Sequencing of Date Palm (Phoenix dactylifera L.) Cultivars Using NGS.

“…However, with the advent of NGS, markers are used to review as many loci as possible throughout the entire genome and with nucleotide-level precision (Varshney et al, 2014). The development of DNA markers using nextgeneration sequencing (NGS) technology became the most effective way in improving date palm valuable resources (Cullis, 2011;Faqir et al, 2017). In addition, a major step in understanding the genetic basis of an organism is the complete sequences studies (Sterky and Lundeberg, 2000).…”

Molecular characterization of a species in the genus Rubus in Boyacá, Colombia

“…(CASTILLO et al, 2010). Molecular markers represent a fast, objective method, use simple techniques, are not affected by environmental conditions, are used in plants regardless of their phenology, and are efficient when discriminating genotypes in the same species (FAQIR et al, 2017). Using molecular markers for the characterization of a species are a useful instrument to describe morphologically similar individuals with agronomic potential that present a certain capacity to adapt to climate change (EL KADRI et al, 2019).…”