Effect of Temperature during Seed Maturation on the Oil Composition of Low-Linolenic Genotypes of Flax1
- A. G. Green2
The flax (Linum usitatissimum L.) cultivar Glenelg, two low-linolenic genotypes derived from it by induced mutation (M1589, M1722), and a very low-linolenic genotype (“Zero”), obtained by recombination of the M1589 and M1722 mutations, were grown under six post-flowering temperature regimes ranging from 15/10°C (day/night) to 30/25°C. The effect of temperature on seed weight, oil concentration, and fatty acid composition was studied. High temperatures resulted in significantly decreased seed weight in all four genotypes, and decreased oil concentration in Glenelg and Zero. Oil concentration in M1589 and M1722 was below that in Glenelg and Zero at all temperatures and was less sensitive to temperature. In all four genotypes, increased temperature had pronounced effects on the relative proportions of the unsaturated fatty acids; linoleic and linolenic acids were considerably decreased and there was an equivalent increase in oleic acid percentage. The percentages of the saturated fatty acids, palmitic and stearic, increased slightly but significantly with increased temperatures. The alteration in fatty acid composition was due to the marked sensitivity of the oleic acid desaturation step to increased temperature, the subsequent desaturation of linoleic acid being highly temperature stable. In the 15/10°C and 18/13°C treatments, the percentage of linoleic acid in the Zero genotype was > 62% of the total fatty acids, a level that is suitable for manufacturing polyunsaturated margarines and oils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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