SCREENING FOR LOW GRAIN CADMIUM PHENOTYPES IN SUNFLOWER, DURUM-WHEAT AND FLAX

Cadmium (Cd) level in nonoilseed sunflower (Helianthus annuus L.), fla x (Linum usitatissimum L.), and durum wheat (Triticum turgidum L. var. durum) grown on uncontaminated, alkaline soils has exceeded limits es tablished in Northern Europe. Separate field experiments were conducte d to investigate variability of grain Cd levels among sunflower, durum wheat and flax germplasm, and to seek an efficient screening method f or future breeding. There were large variations in leaf Cd concentrati on among 200 sunflower lines. These lines performed more consistently for Cd uptake at the R5 stage than at the V8 stage across 4 locations with markedly differing soils. Cd concentration in V8 leaves was not r elated to Cd in grain. The positive correlation between R5 leaf Cd and kernel Cd level was obtained from nonoilseed hybrid (Sigco 954) (R-2 = 0.74*), and 200 lines (R-2 = 0.44**) tested over 4 locations in 2 f ield trials, respectively. This indicates that an efficient and low co st screening method can be developed for genotype selection, but plant s must be grown to the R5 stage. A preliminary evaluation of 30 durum wheat and 74 flax lines indicated large variations in grain Cd level o f durum wheat and flax. Grain Cd concentration ranged from 0.11 to 0.3 4 mg Cd kg(-1) DW for durum wheat, and 0.14 to 1.37 mg Cd kg(-1) DW fo r flax, respectively. This variability indicates that breeding for low grain Cd in durum wheat and flax should be feasible.