# Combinations of mutations in the raffinose synthase genes and the fatty acid desaturase genes for improvement of soybean oil and meal traits

## TL;DR

This study shows how combining specific gene mutations in soybeans can improve oil and meal quality by increasing healthy fats and reducing indigestible sugars.

## Contribution

The novelty lies in combining multiple gene mutations to simultaneously enhance soybean oil and meal traits through conventional breeding.

## Key findings

- Combining four mutant alleles produced high oleic soybeans with less than 2% raffinose and stachyose.
- Six gene combinations achieved high oleic, low linolenic soybeans with no negative impact on protein or oil content.
- Improved traits were consistent across three growing seasons.

## Abstract

Soybean (Glycine max) meal and oil are important agricultural products, with soybean oil accounting for 55% of US vegetable oil consumption and soybean meal for 69% of global protein meal consumption. The ideal soybean oil profile for food applications is an oil high in the monounsaturated oleic acid, yet low in polyunsaturated fat which may result in instability and off-flavors. Soybean seeds also produce a limited amount of raffinose and stachyose, which are not digestible by non-ruminant animals, and limit the uses of soybean in meal and other food products. In recent years, efforts in soybean genetics have identified gene variants that can achieve the ideal oil profile and limit the biosynthesis of raffinose and stachyose in the seed. In this work conventional breeding techniques were employed to combine mutant alleles of genes for altered fatty acid and carbohydrate content, and the resulting lines were evaluated for additivity on aspects of seed composition. We found that we could obtain high oleic (> 75%) soybeans with < 2% of the seed mass comprising raffinose and stachyose using a combination of four mutant alleles. High oleic-low linolenic soybean with less than 3% linolenic acid, > 75% oleic acid and raffinose and stachyose < 2% of the seed weight were obtained by combining six genes. Composition changes were consistent over three growing seasons and no detrimental effects on overall seed protein or oil content were observed.

The online version contains supplementary material available at 10.1007/s11032-026-01636-x.