DEVELOPMENT AND CHARACTERIZATION OF GENETIC RESOURCES FOR AGRONOMIC AND QUALITY TRAITS USING GENOMIC TOOLS
Location: Dale Bumpers National Rice Research Center
Title: Total grain-arsenic and arsenic-species concentrations in rice as impacted by genotype and water management
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2009
Publication Date: November 3, 2009
Citation: Pillai, T.R., Yan, W., Agrama, H.A., James, W.D., Ibrahim, A.M., Gentry, T.J., McClung, A.M. 2009. Total grain-arsenic and arsenic-species concentrations in rice as impacted by genotype and water management [abstract]. Proceedings of 2009 International Annual Meetings of ASA-CSSA-SSSA, November 1-5, 2009, Pittsburgh, Pennsylvania. CDROM.
Recent studies have indicated that high soil arsenic (As) concentrations can result in decreased rice (Oryza sativa L.) grain yields and increased grain-As concentrations. Low As-concentration in rice grain is especially desirable for populations that rely upon rice as a staple food and live where drinking and irrigation waters have As-concentrations. The present study involved testing of a collection of indica and japonica rice genotypes from the USDA World Germplasm Collection for grain-As concentration and speciation under two water-management systems (continuous-flood and intermittent-flood) and under two soil-As treatments (native soil with approximately 5 mg As/kg and a soil treated with monosodium methylarsenate [MSMA] with approximately 19 mg As/kg). The total rice-grain As (TGAs) and As-species concentrations of the genotypes were evaluated with respect to rice-plant traits (including heading date, yield, and straighthead-susceptibility rating). TGAs concentrations with the MSMA treatment were considerably higher than with the native-soil treatment. The predominant forms of As extracted from the rice grain were the organic species, dimethylarsinic acid (DMAsV), and inorganic AsIII (iAsIII). TGAs, DMAsV and iAsIII concentrations were each significantly different by soil-As concentration, water management and genotype. Compared to continuous-flood, the intermittent-flood treatment reduced TGAs concentrations by 59 and 51% with the native and MSMA-treated soils, respectively. In the native soil, DMAsV concentration was considerably higher with the continuous-flood treatment, accounting for 64 to 40% of total grain-As accumulation, whereas with the intermittent-flood treatment DMAsV proportion was lower (46 to 1%). The intermittent-flood treatment was successful in lowering potentially harmful iAsIII concentrations up to 47%. Lower TGAs, DMAsV, and iAsIII concentrations were in general observed in the high-yielding and early-maturing genotypes. This study demonstrates the potential of genotype selection in combination with water management to produce rice with acceptably low TGAs, DMAsV and iAsIII concentrations.