STUDIES RELATING TO THE INHERITANCE OF ALTERED FATTY ACID CONTENT IN GLYCINE MAX (LINOLENIC ACID)
Abstract
Significant variation in linolenic acid (18:3) levels during seed development was observed in Century and the low linolenic acid mutant, C1640. The linolenic acid percentage in C1640 seeds was equal to or higher than that in Century seeds at 20 days after flowering. However C1640 was consistently lower in linolenic acid than Century by seed maturity. Ontological changes were similar whether seeds were sampled from upper or lower nodes and whether seeds were dried or frozen after sampling. Seeds harvested from different parts of the plant varied significantly in oleic acid (18:1) and linolenic acid levels for Century and in oleic acid, linoleic acid (18:2) and linolenic acid levels for C1640. Most of the variation in oil composition within genotypes occurred in oleic and linoleic acid percentages and was associated with nodal variation. Five of the six mutant lines selected from mutagenized seed of Century for altered oil composition were close to Century for the agronomic traits of height, maturity, and lodging and also were close in seed protein and oil percentages. Several lines were not significantly lower in yield than Century. In crosses among the six lines and Century, hybrid oil composition was largely determined by the genotype of the embryo. Some maternal influence was present however, affecting levels of oleic and linoleic acids more than levels of palmitic (16:0), stearic (18:0), or linolenic acids. Simple inheritance was observed in all crosses segregating for percent palmitic acid, percent stearic acid, or percent linolenic acid. Gene action was additive for levels of palmitic acid and linolenic acid and partially dominant for low (normal) stearic acid levels. Single-gene segregation for oleic acid levels with dominance for a high (normal) level of oleic acid was observed in one cross. The inheritance of oleic and linoleic acid percentages was unclear in most of the crosses segregating for these fatty acids. Hybrids generally had levels of oleic and linoleic acid intermediate between the parents, indicating additive gene action. The presence of strong environmental and maternal influences obscured segregation for these fatty acids.
Degree
Ph.D.
Subject Area
Agronomy
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