International Journal of Molecular Evolution and Biodiversity 2024, Vol.14, No.5, 229-240 http://ecoevopublisher.com/index.php/ijmeb 234 genomic sequencing technologies. Techniques such as cluster analysis and analysis of molecular variance (AMOVA) have been used to assess genetic variation and population structure, revealing significant genetic divergence between populations and identifying distinct genetic clusters (Na et al., 2016; Thant et al., 2021). Additionally, methods like the unweighted pair group method with arithmetic mean (UPGMA) and principal coordinate analysis (PCA) are frequently employed to construct dendrograms and visualize genetic distances among rice genotypes. These approaches provide valuable insights into the genetic diversity and evolutionary relationships of Myanmar’s rice landraces (Yadav et al., 2019; Sao et al., 2020). 5 Key Findings from Genetic Diversity Studies in Myanmar 5.1 Genetic variation within and between landrace varieties Genetic diversity within and between Myanmar’s rice landrace varieties has been extensively studied using various DNA markers. For instance, a study using DArTseq technology revealed significant genetic variance among 117 rice genotypes, with SNPs ranging from 0 to 0.753 and silicoDArT markers from 0.001 to 0.954. This study identified two distinct population groups and highlighted a significant divergence between traditional Pawsan varieties and modern high-yielding varieties, with 74% genetic variation at the population level (Thant et al., 2021). A genetic analysis of Myanmar’s rice landraces using SSR markers was conducted and found considerable genetic variation both within and between populations. The study identified several unique alleles that are not found in other regional varieties, suggesting that Myanmar’s rice germplasm contains novel genetic materials that could be valuable for future breeding efforts (Yamanaka et al., 2011). Additional research by Watanabe (2016) explored the genetic diversity of Myanmar’s rice landraces using morphological and molecular markers, including SSR markers, to assess the genetic relationships among 150 rice accessions. This study found that Myanmar’s landrace varieties clustered into distinct genetic groups, indicating substantial genetic diversity and differentiation between upland and lowland ecotypes. Another study evaluated 175 rice accessions from different ecosystems in Myanmar, confirming high genetic diversity and classifying the accessions into two main cluster groups corresponding to indica and japonica groups (Na et al., 2016). These findings underscore the rich genetic diversity present within Myanmar’s rice landraces, which is crucial for future breeding programs. 5.2 Identification of unique genetic traits Unique genetic traits have been identified in Myanmar’s rice varieties, particularly in aromatic rice. A study focusing on aromatic rice varieties discovered new BADH2 variants associated with aroma, including a 43 bp deletion in the 3’ UTR and a particular BADH2 allele with a 3 bp insertion, which was 100% associated with aroma (Myint et al., 2012). Additionally, the evaluation of physicochemical characteristics and genetic diversity of widely consumed rice varieties in the Kyaukse area identified superior cooking and eating quality traits in the famous Myanmar rice variety, Paw San Bay Kyar (PSBK), which exhibited intermediate amylose content, intermediate gelatinization temperature, soft gel consistency, and the highest elongation ratio among the studied varieties (Myint et al., 2023). These unique genetic traits are valuable for enhancing the quality and marketability of Myanmar’s rice. 5.3 Comparative studies with improved varieties Comparative studies between landraces and improved rice varieties have highlighted the genetic distinctions and potential advantages of landraces. For example, a study using whole genome resequencing of 20 rice accessions, including javanica and indica, revealed significant genomic variations and identified candidate genes related to grain shape, such as TGW2, which performed better in landraces (Long et al., 2022) (Figure 2). Another study assessed the genetic diversity of traditional landraces and improved cultivars, finding higher genetic variations and observed heterozygosity in landraces compared to modern cultivars. This study also identified key genes involved in domestication and improvement, such as Kala4 and Ghd7, which are crucial for future breeding efforts (Zahra et al., 2020). One notable study comparing the genetic diversity of Myanmar’s landrace rice with improved varieties highlights the unique genetic variations present in landrace varieties. Conducted by Yamanaka et al. (2011), the study found that Myanmar’s landrace rice possesses distinct genetic variations that contribute
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