International Journal of Molecular Evolution and Biodiversity 2024, Vol.14, No.5, 229-240 http://ecoevopublisher.com/index.php/ijmeb 230 Recent research has underscored the rich genetic diversity found in Myanmar’s rice varieties, a significant reservoir of rice genetic resources. Thant et al. (2021), using DArTseq technology, identified two distinct population groups among 117 rice genotypes from the Ayeyarwady delta. Watanabe et al. (2016) evaluated 175 rice accessions from across Myanmar, revealing high genetic diversity and classifying them into indica and japonica groups. Furuta et al. (2024) contributed to the development of genomic resources for Myanmar’s rice germplasm by creating a diversity panel of 250 accessions and assembling a de novo genome of the Inn Ma Yebaw variety. These resources are intended to advance genetic research and breeding programs. Furthermore, Yan et al. (2010) analyzed the USDA Rice World Collection and found that the germplasm accessions from Myanmar were among the most diverse globally. Collectively, these studies highlight the critical role of Myanmar’s rice landraces in maintaining genetic diversity and their potential to enhance rice breeding efforts. This study aims to synthesize current knowledge and existing research on the genetic diversity of Myanmar’s core landrace rice varieties. This includes an examination of the methodologies used to assess genetic variation, such as DArTseq-based SNP and silicoDArT markers, microsatellite loci, and functional molecular markers. Additionally, the study highlights the significance of these genetic studies in identifying useful DNA polymorphisms and specific genes that confer desirable phenotypic traits. By consolidating these findings, the study seeks to provide a comprehensive understanding of the genetic landscape of Myanmar’s rice varieties and their potential applications in rice breeding and conservation efforts. 2 Genetic Diversity in Rice: An Overview 2.1 Definition and importance of genetic diversity Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is crucial for the adaptability and survival of populations, as it allows species to adapt to changing environmental conditions, resist diseases, and maintain ecosystem stability. In rice, genetic diversity is essential for breeding programs aimed at improving yield, disease resistance, and stress tolerance. The adaptability of a population is closely linked to its genetic variation, which influences fitness-related traits growth rate, reproductive success, and resistance to environmental stressors (Booy et al., 2000; Zhu et al., 2000). 2.2 Methods for assessing genetic diversity Several methods are employed to assess genetic diversity in rice, each providing different levels of resolution and insights into the genetic makeup of populations Molecular markers such as Single Nucleotide Polymorphisms (SNPs) and Simple Sequence Repeats (SSRs) are commonly used. SNP markers provide detailed insights into genetic variation and population structure, as demonstrated in studies using Diversity Array Technology (DArT) based SNP markers. Recent studies have demonstrated the effectiveness of SNP markers using Diversity Array Technology (DArT)-based platforms to analyze genetic diversity in rice, revealing fine-scale population differentiation and adaptation patterns (Adeboye et al., 2020; Kimwemwe et al., 2023). SSR markers are also widely used due to their high polymorphism and ability to reveal genetic relationships among different rice cultivars (Jin et al., 2010; Chung et al., 2023). They have been successfully used to characterize genetic diversity and determine parentage in breeding programs (Jin et al., 2010; Chung et al., 2023). Other molecular markers, such as Amplified Fragment Length Polymorphisms (AFLPs) and Random Amplified Polymorphic DNA (RAPD), have also been used to analyze genetic diversity, although their use has declined with the advent of high-throughput sequencing methods. Next-Generation Sequencing (NGS) technologies, including whole-genome sequencing and genotyping-by-sequencing, provide comprehensive data on genetic variation, allowing for the identification of millions of SNPs and structural variations (Wang et al., 2018; Zhang et al., 2021). Genome-wide association Studies (GWAS) can assess genetic diversity in rice by identifying genetic variants linked to key traits and uncovering population structure. Zhao et al. (2011) used GWAS to analyze SNPs in diverse rice germplasm, revealing rich allelic diversity and population stratification. This method also highlights haplotype diversity and linkage disequilibrium patterns, offering valuable insights for rice breeding and genetic improvement. Additionally, genomic analyses, such as those conducted in the 3k Rice Genomes Project, offer comprehensive data on genetic variation and structural variations within rice populations (Figure 1) (Wang et al., 2018; Zhang et al., 2021).
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