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 asso ciated with poor oil quality. The soybean line M-5, develoaed by mutag enesis 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 effe ct 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 a cid in both F-2 seeds and plants was distributed as a trimodal pattern and the results indicated that the low, intermediate and normal conte nts of this fatty acid were in 1 : 2 : 1 ratio. The low and intermedia te 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 b y a single major gene, acting in an additive manner. Due to the absenc e of maternal and cytoplasmic effects, and since a single major gene c ontrolled the linolenic acid, the M-5 mutant could be used in a breedi ng program to improve the variety with low linolenic acid content.