CANDIDATE GENE-TARGETED TRAP MARKER ANALYSIS REVEALS GENETIC DIVERSITY AMONG RICE (ORYZA SATIVA L.) GERMPLASM FOR IRON BIOFORTIFICATION

Abstract

Iron deficiency remains one of the most prevalent micronutrient disorders worldwide, particularly in populations that rely heavily on rice as a staple food. Developing rice cultivars with enhanced grain iron content requires a comprehensive understanding of the genetic diversity present in iron-related genes. In the present study, Target Region Amplification Polymorphism (TRAP) markers derived from candidate iron transporter genes were employed to evaluate the genetic diversity of 30 rice (Oryza sativa L.) genotypes. Thirty gene-specific primers targeting iron transport and homeostasis related loci were paired with two arbitrary primers (ME02 and ME05) to generate polymorphic DNA profiles. The primer combinations produced a total of 703 scorable amplification products ranging from 50 to 800 bp, of which 654 (93.0%) were polymorphic and 49 (7.0%) were monomorphic, demonstrating a high level of genetic variability among the evaluated germplasm. The polymorphic information content (PIC) values ranged from 0.09 to 0.25, with an average of 0.22, indicating moderate to high discriminatory power of the candidate gene-based TRAP markers. Cluster analysis based on UPGMA grouped the genotypes into two major clusters, while Bangara kovi and Jeerige sanna formed distinct solitary branches, reflecting their unique genetic constitution. The observed genetic relationships indicate substantial diversity within the studied germplasm and demonstrate the effectiveness of candidate gene-targeted TRAP markers in detecting functional polymorphisms associated with iron transporter genes. These findings provide valuable information for marker assisted breeding, association mapping, and the development of iron-biofortified rice cultivars.