# Effect of the genetic and environment interaction on yield, Fe and Zn content among locally cultivated common bean (Phaseolus vulgaris L.) germplasm

## TL;DR

This study explores how genetics and environment affect common bean yield and nutrient content to guide breeding for better nutrition and productivity.

## Contribution

The study integrates multi-environment evaluation and multi-trait selection to identify high-yielding, nutrient-dense common bean genotypes.

## Key findings

- Genotype and environment significantly influence grain yield, iron, and zinc content in common beans.
- High heritability for iron and zinc suggests genetic improvement is feasible.
- Multi-trait selection index identifies genotypes with both high yield and micronutrient density.

## Abstract

Common bean (Phaseolus vulgaris L.) is a key source of dietary protein and micronutrients, in low- and middle-income countries. Improving both yield and micronutrient density requires a clear understanding of genotype (G), environment (E), and genotype-by-environment interaction (GEI) effects to support nutrition-sensitive breeding strategies.

This study assessed the effects of G, E, and GEI on grain yield and micronutrient concentration using the Additive Main Effects and Multiplicative Interaction (AMMI) model. A total of 83 bush and 84 climbing common bean genotypes were evaluated across three locations and two cropping seasons (2024A–2024B) in Burundi. AMMI and GGE biplot analyses were applied to examine genotype performance, stability, and adaptation across environments. Broad-sense heritability was estimated for yield and micronutrient traits, and a multi-trait selection index (MTSI) was used to identify superior genotypes combining agronomic and nutritional attributes.

Combined AMMI-analysis revealed highly significant (p <0.001) effects of genotype and environment on grain yield, iron (Fe), and zinc (Zn), together with significant GEI for most traits. Significant genetic variation was observed for Fe (52.86–76.5 ppm in bush beans; 53.38–59.7 ppm in climbing beans), Zn (≈17–23 ppm), and grain yield (≈950–2240 kg ha-1). Several genotypes surpassed check varieties for Fe and Zn, though enhanced micronutrient levels were not consistently associated with high yield. AMMI and GGE biplots identified both stable, high-performing genotypes and those with specific environmental adaptation. Broad-sense heritability was high for Fe and Zn (h2 = 0.68–0.82) but low for yield (h2 ≈ 0.30–0.33). The multi-trait selection index (MTSI) effectively identified genotypes combining good yield and micronutrient density.

These findings highlight the importance of integrated multi-environment evaluation and multi-trait selection for developing high-yielding, micronutrient-dense common bean varieties adapted to diverse agro-ecologies.