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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF SOYBEAN GENEOTYPES AND MANAGEMENT SYSTEMS FOR EARLY SEASON AND STRESS ENVIRONMENTS

Location: Crop Genetics Research Unit

Title: Effects of genetics and environment on fatty acid stability in soybean seed

Authors
item Bellaloui, Nacer
item Mengistu, Alemu
item Kassem, Abdelmajid -

Submitted to: Food and Nutrition Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 2, 2013
Publication Date: August 21, 2013
Citation: Bellaloui, N., Mengistu, A., Kassem, A. 2013. Effects of genetics and environment on fatty acid stability in soybean seed. Food and Nutrition Sciences. 4:165-175.

Interpretive Summary: Although soybean seed oil production and composition (individual fatty acids in the oil: palmitic, stearic, oleic, linoleic, and linolenic acids) are genetically controlled, changes of oil level and fatty acid composition across genotypes and environments such as drought and temperature were observed. The mechanisms of how genotypes interact with environment, affecting oil production and composition, are still not well understood. The objective of this research was to investigate the effect of drought/water stress and temperature on soybean genotypes (varieties). A repeated greenhouse experiment to study the effect of water stress and a repeated growth chamber experiment to study the effect of temperature were conducted. The results showed that both water stress and high temperature altered seed oil composition by increasing oleic acid and decreasing linoleic and linolenic acid concentrations. Soybean seed with high oleic and low linoleic and linolenic fatty acid concentrations is desirable. Severe water stress or high temperature such as 40/33 oC resulted in higher palmitic acid and lower stearic acid. Genotypes differed in their responses to water stress or temperature. Analyses of seed carbohydrates (sugars) (such as glucose, fructose, sucrose, raffinose, and stachyose) showed a significant decline of glucose, fructose, and sucrose and a significant increase of stachyose concentrations by water stress and high temperature. Analyses of nitrogen and carbon isotopes showed changes in sources of nitrogen and carbon fixation, affecting nitrogen and carbon processes during seed maturation. The research demonstrated that both water stress and high temperature altered oil production and composition, and this could be partially related to limited availability of carbohydrates within the plants and movement of carbohydrates from leaves to seed. The research provides scientists with useful information on water stress and high heat effects on oil production and composition. Also, the research provides breeders with information that aids selection for desirable seed oil traits under drought and high heat conditions.

Technical Abstract: Although seed oil production and composition are genetically controlled, changes of oil level and oil composition across genotypes and environments such as drought and temperature were observed. The mechanisms of how genotypes interact with environment, affecting oil production and composition, are still not well understood. The objective of this research was to investigate the effect of drought/water stress and temperature on soybean genotypes. Two soybean genotypes of maturity group (MG) II (PI 597411 B and PI 597408) and two of MG VI (Arksoy and PI 437726) were used. A repeated greenhouse experiment to study the effect of water stress and a repeated growth chamber experiment to study the effect of temperature were conducted. The results showed that both water stress and high temperature altered seed oil composition by increasing oleic acid and decreasing linoleic and linolenic acid concentrations. Severe water stress (soil water potential between –150 to –200 kPa) or high temperature (40/33 oC, day/night) resulted in higher palmitic acid and lower stearic acid. Genotypes differed in their responses to water stress or temperature. Analyses of seed carbohydrates (glucose, fructose, sucrose, raffinose, and stachyose) showed a significant decline of glucose, fructose, and sucrose and a significant increase of stachyose concentration by water stress and high temperature. Analyses of natural abundance of delta 15N and delta13C isotopes showed changes in sources of nitrogen and carbon fixation, possibly affecting nitrogen and carbon metabolism pathways. The research demonstrated that both water stress and high temperature altered oil production and composition, and this could be partially related to limited availability and movement of carbohydrates from leaves to seed. Further research to investigate the enzymes controlling fatty acids conversion and nitrogen and carbon metabolism is needed.

Last Modified: 7/22/2014
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