- E Hajari, D Nonyane and RB Cronje
- 2021
- Volume: 24
- Pg 48-52
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It is well known that there is significant confusion surrounding the naming and identification of litchi cultivars and selections. Currently, cultivars are identified and described using morphological characteristics but these can be influenced by environmental and other factors leading to misidentifications. Molecular markers provide a tool that can be used to supplement morphological characterisation, particularly in cases where confusion exists. Therefore, the current project investigated the suitability of Simple Sequence Repeat (SSR) markers for DNA fingerprinting. In addition, this type of molecular characterisation also allows for investigation of the genetic relationships between tested cultivars. Molecular markers from two published sources were compared. The results showed that while both sets of markers were suitable for determining the relationships between morphological and molecular characteristics, the markers developed by Viruel and Hormaza (2004) were more informative for DNA fingerprinting. The limit of resolution of these markers were tested and it was established that the markers could distinguish between groupings of cultivars but could not identify individual cultivars. Nevertheless, the markers allowed for the creation of a molecular genotype reference database for cataloguing the germplasm available in the breeding programme.
Summary:
The article discusses the use of DNA molecular markers, specifically single nucleotide polymorphisms (SNPs), for fingerprinting and identifying selected litchi cultivars, addressing confusion in cultivar nomenclature and genetic relationships.
From an initial set of 148 SNP markers, 90 high-quality SNPs were used for genetic analysis across 96 litchi accessions, revealing a wide genetic diversity and identifying 94 distinct genotypes.
A minimal set of 14 SNP markers was found sufficient to distinguish all 85 non-redundant genotypes, showing high stability and reliability when tested on multiple plants per cultivar, representing phenotypic and geographic diversity.
The 14 SNP set can serve as a robust DNA barcode for cultivar identification, aiding in germplasm management, breeding programs, and protection of cultivar rights.
This molecular fingerprinting approach enables clear discrimination among cultivars, detection of synonymies, homonymies, and provides a basis for genetic conservation and varietal improvement in litchi.