Rice (Oryza sativa L.) landraces represent a valuable genetic resource that can play an important role in sustainable crop production and biodiversity conservation for the future. However, the cultivation and genetic diversity of these landraces in the Mekong Delta have been unacceptable due to widespread adoption of high-yielding rice cultivars and intensive farming practices, leading to environmental degradation and biodiversity losses. The following study evaluated the morphological and grain traits of 65 rice landraces from the Mekong Delta, conserved in the Gene Bank of Can Tho University, Vietnam. The landraces underwent cultivation in field conditions and assessment based on the evaluation system of the International Rice Research Institute (IRRI), Philippines. Grain quality analysis focused on grain size and shape. The genome-wide association study was successful in identifying the genomic regions linked to the morpho-agronomic traits in landraces of the Mekong Delta using single nucleotide polymorphisms (SNPs). Correlation analysis helped link the genetic characteristics with 11 traits, and candidate genes associated with 681 significant SNPs attained identification using the Rice SNP-Seek Database. The findings provided valuable insights into the genetic and phenotypic diversity of rice landraces for further improvement and germplasm conservation in the Mekong Delta, Vietnam.

Keywords: Rice (O. sativa L.), landraces, genetic variations, biodiversity, agronomic traits, candidate genes, GWAS

Key findings: This study identified 46 candidate SNPs within 32 genes associated with 11 agronomic traits in 65 rice (O. sativa L.) landraces. Plant height and brown rice shape are the key traits for breeding, with new candidate SNPs linked to them.