INHERITANCE OF LOW LINOLENIC ACID CONTENT IN SOYBEAN MUTANT LINE M-5

Linolenic acid is the unstable component of soybean [Glycine max (L.) Merr.] oil responsible for undesirable odors and flavors commonly associated with poor oil quality. The soybean line M-5, develoaed by mutagenesis from Bay, had a half of linolenic acid content compared to that of the original variety. Reciprocal crosses of both F-1 seeds and F-1 plants did not differ significantly, which indicated no maternal effect on linolenic acid content. Cytoplasmic inheritance was not observed based on the lack of reciprocal differences for linolenic acid in the analysis of both F-2 seeds and F-2 plants. The content of linolenic acid in both F-2 seeds and plants was distributed as a trimodal pattern and the results indicated that the low, intermediate and normal contents of this fatty acid were in 1 : 2 : 1 ratio. The low and intermediate linolenic acid contents in the seeds of B-1, acid intermediate and normal contents in the seeds of B-2 were fitted with the ratio of 1 : 1. These results indicated that linolenic acid in M-5 was controlled by a single major gene, acting in an additive manner. Due to the absence of maternal and cytoplasmic effects, and since a single major gene controlled the linolenic acid, the M-5 mutant could be used in a breeding program to improve the variety with low linolenic acid content.