Evaluating genetic diversity and seed composition stability within Pan-African Soybean Variety Trials

Authors: MEYER, ELIZABETH - University Of Missouri; PRENGER, ELIZAETH - University Of Missouri; MAHMOOD, ANSER - University Of Missouri; DIERS, BRIAN - University Of Illinois; SANTOS, FONSECA - University Of Illinois; CHIGEZA, GOLFREE - International Institute For Tropical Agriculture; Song, Qijian; MWADZINGENI, LEARNMORE - Seed Co Group Harare; MUKARO, RONICA - Department Of Research And Specialist Services; SCABOO, ANDREW - University Of Missouri

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2024
Publication Date: 9/29/2024
Citation: Meyer, E., Prenger, E., Mahmood, A., Diers, B., Santos, F., Chigeza, G., Song, Q., Mwadzingeni, L., Mukaro, R., Scaboo, A. 2024. Evaluating genetic diversity and seed composition stability within Pan-African Soybean Variety Trials. Crop Science. https://doi.org/10.1002/csc2.21356.
DOI: https://doi.org/10.1002/csc2.21356

Interpretive Summary: Soybean is a globally valuable crop due to its high protein and oil content and wide range of uses in food and industrial applications. However, African soybean production accounts for only 1.3% of the world's total production. USAID and other organizations are developing plans to increase soybean production in Africa, particularly in sub-Saharan Africa (SSA). One component of the program is the Pan-African Soybean Variety Trial (PAT), a cross-continental field effort to evaluate soybean varieties in a wide range of environments. As part of this program, this study aims to identify the best performing varieties based on seed protein and oil content and the stability of the contents in different environments. The study recommends stable varieties and their most suitable planting locations to breeders and producers. Additionally, the study explores the genetic diversity of PAT varieties, provides insight into their relationship to USDA soybean collections, and highlights genetically unique germplasm for future breeding programs. This research provides valuable information to support SSA soybean cultivation and new variety development.

Technical Abstract: Given the high cost of animal protein, protein deficiency is a prevalent form of malnutrition in sub-Saharan Africa (SSA). Soybean could provide a potential cheaper quality protein source and could fortify lysine-limited cereal-based diets. Breeding soybean for seed composition in SSA requires an understanding of genotype by environment interaction (G × E). African breeding programs submit cultivars for evaluation in the Pan-African Soybean Variety Trials (PAT), providing the opportunity to examine G × E across diverse environments. With PAT data, we conducted additive main effects and multiplicative interaction (AMMI) analysis and genotype plus genotype-by-environment (GGE) biplot analysis on seed protein and oil content of 17 cultivars grown with two replications in 9 environments across Zimbabwe. Protein ranged from 322.8 g kg-1 to 445.1 g kg-1 and oil ranged from 164.8 g kg-1 to 242.7 g kg-1. For protein AMMI analysis, MAKWACHA performed best for both stability and stability plus content. For oil AMMI analysis, SC SPIKE performed best for stability and KALEYA performed best for stability plus content. GGE biplot analyses identified 3 mega-environments for both protein and oil, with SC EXPT2, KALEYA, and SC EXPT1 winning for protein, and TGX 2002-9FM, LUKANGA, and SC EXPT3 winning for oil. We also evaluated genetic diversity of 19 PAT cultivars through phylogenetic analyses with 1,059 USDA GRIN diversity panel accessions. The identified stable and adaptable PAT cultivars are recommended for utilization by breeders and producers, while genetically distinct accessions with valuable traits are highlighted as a resource for integration into breeding programs.