Mineral composition of oil-free seeds of Brassica napus, B. rapa and B. juncea as affected by location and year

Three cultivars of Brassica (Westar, Brassica napus; Tobin, B. rapa; Cutlas s, B. juncea) were grown in four locations in 4 successive years, with dupl icate samples taken from each treatment. Harvested seed was hexane-extracte d, ground and analyzed for mineral content. The average contents (mg kg(-1) ) were: Ca, 0.64; P, 1.12; Mg, 0.56%; Cu, 6.2; Zn, 46; Fe, 188; and Mn, 55. Values for Westar and Tobin were generally similar but Cutlass contained l ess Ca, Mg, Fe and Mn and more Cu and Zn (P < 0.01). Locations affected all mineral levels. One location produced samples lower in Ca, P, Cu and Mn bu t higher in Zn than the other locations (P < 0.01). Year-to-year variabilit y was of minor consequence.