Abstract

Rice is the staple food in the Republic of Guinea. However, its production is seriously hampered by iron toxicity. The fight against this stress necessarily involves the search for tolerant or resistant varieties. The study aims to determine quantitative trait locus (QTL) associated with tolerance to iron toxicity and to identify genotypes tolerant or resistant to iron toxicity. Thus, 90 local rice accessions collected in two regions of Guinea with high iron toxicity were evaluated using 33,537 single nucleotide polymorphism (SNP) markers. Seventy of the SNP markers expressed a polymorphism rate of 100%. Diversity analysis of the entire collection with these markers revealed a total of 140 alleles, a moderate Nei genetic diversity of 0.426, a fairly high Shannon diversity index of 0.610 and an organization of the accessions into four genetic groups. The study also identified 12 potentially iron-tolerant accessions and five QTLs associated with iron-toxicity tolerance located on chromosomes 1, 2, 3, 11, and 12. The 12 genotypes identified could be exploited in the lowland rice breeding program.

Key words: Oryza, abiotic stress, molecular characterization, variability, molecular markers.