GENETIC-ANALYSIS OF PALMITIC ACID CONTENTS USING 2 SOYBEAN MUTANTS, J3 AND J10

Development of soybean [Glycine max (L.) Merr.] varieties with altered palmitic acid content increase the utility of the oil for different e dible purposes. The palmitic acid content in the seed oil of common so ybean varieties is about 11.0%. Soybean mutants with reduced and eleva ted palmitic acid have been developed. The objective of this study was to determine the relationships between the genetic systems controllin g palmitic acid content in these mutants. Reciprocal crosses were made between each mutant and its original variety, Bay and between the two mutants. No maternal and cytoplasmic effects were found in these cros ses. There was no dominance for palmitic acid content in J3 x Bay and J3 x J10 crosses, while in J10 x Bay cross, a partial dominant effect was observed. Analysis of F-2 seeds from F-1 plants in both of J3 x Ba y and J10 x Bay crosses showed three distinct peaks for palmitic acid content which satisfactorily fit a 1 : 2 : 1 ratio. Frequency distribu tions for palmitic acid content in J3 x J10 cross showed five peaks in the F-2 seeds and one, three or five peaks in the F-3 seeds from indi vidual F-2 plants. Chi-square analyses for both F-2 and F-3 generation s satisfactorily fit a 1 : 4 : 6 : 4 : 1 ratio. These results indicate that alleles from two different loci with no dominant effect controll ed the palmitic acid content in J3 and J10 mutants. The alleles in J3 and J10 were given the temporary designation of sop1 (J3) and sop2 (J1 0) until their relationships to other alleles for altered palmitic aci d content can be justified.