Soil moisture affects fatty acids and oil quality parameters in peanut

Document Type: Research Paper

Authors

1 Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand.

2 Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.

3 Crop Genetics and Breeding Research Unit, USDA/ARS, Coastal Plain Experiment Station, Tifton, Georgia 31793, USA.

Abstract

Drought affects yield of peanut, but its effect on oleic and linoleic acids that
influence its oil quality of peanut genotypes with different levels of drought
resistance has not been clearly investigated. Therefore, the aims of this research
were to determine whether soil water levels could affect oil quality by changes in
fatty acid compositions of peanut, and to investigate the changes in oil characters in
peanut genotypes with their potential drought resistance under different water
regimes. Field experiments were conducted in split-plot designs with four
replications during dry season for two years (2003/04 and 2004/05). Three water
regimes [field capacity (FC), 2/3 available soil water (2/3 AW) and 1/3 available
soil water (1/3 AW)] were assigned as main-plots, and six peanut genotypes were
assigned as sub-plots. The data were recorded at maturity for fatty acid
compositions and % oil. Seed samples were analyzed for % oil by Soxtec System
HT, and fatty acid compositions were analyzed by gas liquid chromatography.
Differences among water regimes and peanut genotypes were significant for oleic
and linoleic acids content and their ratio (O/L ratio), unsaturated to saturated fatty
acid ratio (U/S ratio) and iodine value (IV). Genotype × water regime interactions
were also significant for all characters. Drought improved the oil quality by
significant increase in oleic acid and O/L ratio, and reduced the linoleic acid, IV
and U/S ratio. Peanut genotypes with different levels of drought resistance
displayed similar tendency in fatty acid characters under drought conditions.

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