Potentially toxic elements concentration in milled rice differ among various planting patterns

• Various planting patterns and cultivars were compared for PTEs concentration in milled rice.
• Less Mn, Co, Ni, Cu, Zn and Cd concentrations in milled rice were observed under DSF than DSA.
• Mo and As in milled rice under DSF were lower than that under TFR and a little higher than DSA.
• Overall, DSF remained superior in terms of less PTEs accumulation and better milled rice yield.
• Rice cultivars also showed variable response to PTEs accumulation.

Soil contamination with potentially toxic elements (PTEs) due to rapid development of industry and agriculture has threatened the food security. Rice, the staple food of more than half of the world's population is thought as the prominent source for intake of PTEs by human beings. In present study, we compared different rice planting patterns, viz., dry direct-seeded aerobic rice (DSA), dry direct-seeded flooded rice (DSF) and transplanted-flooded rice (TFR) regarding PTEs (Mn, Co, Ni, Cu, Zn, Mo, Cd and As) concentration in milled rice and milled rice yield. Two inbred (Lvhan1, Huanghuazhan) and two hybrid (Hanyou3, Yangliangyou6) cultivars were used in present study. We found that Mn, Co, Ni, Cu, Zn and Cd concentrations in milled rice under DSF were lower than that in DSA, and were comparable with that under TFR. Furthermore, Mo and As in milled rice under DSF were lower than that under TFR and a little higher than DSA. Our results also depicted that on average, there were no significant differences in milled rice yield among various planting patterns across cultivars and years. None of the PTE exceeded the critical limits for milled rice except Cd in DSA and As in TFR. Along with the benefits of higher resource use efficiency and less labor requirement; comparable yield with TFR and moderate PTEs accumulation indicated that DSF is a more suitable planting pattern in the context of environmental sustainability. Cultivar variations were also apparent regarding PTEs concentration in milled rice and milled rice yield, which suggested that future studies should focus on breeding/selection of high yielding cultivars with low PTEs accumulation.