Genetic variability of anti‐nutritional factors among soybean (Glycine max.) germplasm

Abstract

Soybean is a vital source of vegetable protein, carbohydrates, oil, and minerals. However, anti-nutritional factors (ANFs) can diminish its nutritional value for monogastric animals, including humans. This study assessed the variability of phytate and trypsin inhibitors in Ugandan soybean germplasm. A total of 308 soybean genotypes were analyzed for yield, phytate, and total trypsin inhibitors (TTI) using spectrophotometric methods. Significant variation was observed for yield, phytate, and TTI levels (p < 0.001). Phytate levels ranged from 14.8 mg kg−1(BSPS 48A-6–3) to 6928.8 mg kg−1(NGDT 2.15–7), while TTI varied from 14.7 mg kg−1(DN 16_N) to 1534.8 mg kg−1(Duiker). Using a weighted selection index, the best-performing genotypes, Ux 990–044, Ux 990–102, and S 6.22B, combined high yield with low ANF levels. Broad-sense heritability (H2) was 0.68 for phytate, 0.84 for TTI, and 0.08 for yield. The phenotypic coefficient of variation (PCV) for phytate (203.1%) was significantly higher than the genetic coefficient of variation (GCV) (137.6%), indicating substantial environmental influence, while moderate for TTI (PCV = 34.6%; GCV = 29.2%). Genetic advance (GA) values were 1667.6 mg kg−1 for phytate and 504.3 mg kg−1 for TTI, highlighting considerable genetic variability and heritability. These findings have practical implications for breeding programs; the identified genotypes that combine high yield and reduced ANFs can reduce processing costs for food and feed industries while enhancing nutritional security, especially in regions dependent on soybean as a protein source.