QTL Analysis of Genetic Tolerance to Iron Toxicity in Rice (Oryza SativaL.) by Quantification of Bronzing Score

A QTL analysis for iron-toxicity tolerance was conducted in rice. Bronzing scores, which are regarded as an index of sensitivity to iron toxicity, were converted to digital data via a scanner and quantified to parametric data using chromaticity coordinates. On the basis of quantified score, QTL analysis for bronzing tolerance was conducted using F3 lines from a cross between a japonica cultivar ‘Gimbozu’ (tolerant) and an indica cultivar ‘Kasalath’ (susceptible). A single QTL near RM221 marker on chromosome 2 was detected by composite interval mapping and additional five QTL were detected by multiple interval mapping. These QTL explained 99% of the total phenotypic variance and they will be used to develop tolerant varieties.