Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/2008
Publication Date: 10/6/2008
Citation: Raghvan, T., Yan, W., Agrama, H.A., James, W.D., Gentry, T.J., Mcclung, A.M., Loeppert, R.H. 2008. Differentiation of rice cultivar for grain arsenic content associated with soil and water management in rice. American Society of Agronomy Abstracts. Paper 41985.
Technical Abstract: Reduction of arsenic (As) in rice grains play an important role in improvement of food quality and minimization of any potential risk from dietary exposure. Twenty-one worldwide cultivars including both indica and japonica subspecies were grown under two water treatments, saturated soil and consistent flooding; and two soils with low and high As. The low As treatment was a native soil with no As application history and the high As soil had received As in the form of monosodium methanearsonate (MSMA) in alternating years for evaluation of straighthead, a physiological disease of rice. The cultivars selected had differential response to straighthead disease. The total arsenic concentration in milled rice grain was determined by ICP-MS following digestion by HNO3/H2O2. Arsenic species were quantified by HPLC-ICP-MS following extraction with 0.16M TFA. The total grain As concentration and speciation varied significantly among the cultivars. Higher total grain As was observed in the flooded soil compared to the saturated soil. Also, grain As increased with higher soil As content. The dominant species of arsenic extracted from the grain were organic DMA (Dimethylarsonate) and inorganic As (III) respectively, but these were highly influenced by soil As content and water management methods. Cultivar susceptibility to the straighthead disease as induced by high soil As was not related to grain-As content or speciation. These results demonstrate the potential of breeding opportunity and field management to produce rice with lower grain As concentrations and lower ratio of inorganic to organic As because the organic As is considerably less toxic.