Genotype × environment influence on African yam bean (Sphenostylis stenocarpa) antinutrients

Abstract

Purpose – This paper aims to determine the influence of genotype and environment on tannins, phytic acid, trypsin inhibitors and haemagglutinin content of African yam bean (AYB). The presence of antinutritional factors (ANFs) alongside hardness-to-cook have been identified as reasons for the neglected and under-utilized status of AYB, a protein-rich legume. Various researchers have focused on ways to reduce these ANFs. However, breeding varieties of AYB with low levels of these ANFs offers a more satisfactory long-term solution to this problem. Design/methodology/approach – Fifteen genotypes of AYB were grown in three different locations – Abakaliki (6° 19′ N 8° 6′ E), Enugu (6° 52′ N 7° 37′ E) and Ibadan (7° 26′ N 3° 53′ E). The locations are representative of the major areas where AYB are produced in Nigeria. Seeds were collected and analysed for the presence of haemagglutinin, phytic acid, trypsin inhibitors and tannin. Findings – Genotype effects were strongest in controlling haemagglutinin content, while environment was the major source of variation for phytic acid, trypsin inhibitors and tannin content. Therefore, variability in the levels of these ANFs in AYB depends largely on the environment where they are grown. Genotype × environment was significant for all the ANFs. Research limitations/implications – The implication of this is that an AYB genotype grown and safely consumed in an environment could have antinutritional effects when grown and consumed in another environment. Originality/value – While research has been carried out on genotypic variations in ANFs of AYB, limited work has been done on the effect of genotype × environment interactions on these ANFs.