A major gene for grain cadmium accumulation in oat (Avena sativa L.)

Cadmium (Cd) is a nonessential heavy metal that is highly toxic to living cells at very low concentrations. Most of the Cd in plants derives from soils. Owing to the large amounts consumed, cereals are the major source of dietary Cd, and Cd content in oat can exceed accepted limits. Plants have a set of mechanisms that control the uptake, accumulation, trafficking, and detoxification of Cd and other metals. Genetic factors affect the variation in Cd level between plant species and cultivars, and the development of cultivars that poorly accumulate Cd is a worthwhile goal. Because of the expense of Cd screening, the use of molecular markers linked to low Cd accumulation could be an alternative to phenotyping for selection. In this study, such markers were sought using bulked-segregant analysis in an F₂ population from the cross between oat cultivars 'Aslak' and 'Salo', the second of which is known to be a high Cd accumulator. Four markers associated with grain Cd concentration were found: 2 RAPDs (random amplified polymorphic DNAs), 1 REMAP (retrotransposon-microsatellite amplified polymorphism), and 1 SRAP (sequence-related amplified polymorphism). The first 3 were converted into more reproducible SCAR (sequence-characterized amplified region) markers. The 4 markers were assigned to 1 linkage group that exhibited a QTL (quantitative trait locus) representing a major gene for grain Cd concentration.