Identifying Mega-environments and Evaluating Grain Yield Stability in Bio-fortified Rice Using AMMI and GGE Approaches

Abstract

The experiment was conducted during July–November, 2022 in Raipur, Bilaspur, Kawardha, Mahasamund, and Jagdalpur districts of Chhattisgarh, India to identify promising rice genotypes under diverse environmental conditions. Thirty micronutrient-rich rice varieties, along with yield and micronutrient checks, were evaluated using RCBD with two replications per location. None of the candidate genotypes outperformed the standard check, Swarna, in combined mean yield performance. AMMI analysis revealed significant genotype, environment, and genotype-by-environment interactions (p<0.05). Environment 5 recorded the highest mean grain yield (6560.75 kg ha^-¹), followed by E₄ (5783.33 kg ha^-¹) and E₂ (5123.67 kg ha^-¹). PCA1 and PCA2 captured 57.49% and 18.61% of genotype-environment interaction, respectively, explaining 76.10% cumulatively. Genotypes G₂₈ and G₂₉ demonstrated high mean yields and stability, suitable for commercial cultivation, while G₁₉ showed high yield but lower stability, indicating potential for specific environments. Genotypes G₂, G₄, and G₁₈, though low-yielding, exhibited greater stability, making them valuable for stability-focused breeding. “Which-won-where” analysis revealed G₁₉ excelling in E₅, G₁₁ performing well in E₁, E₂, and E₃ and G₂₈ succeeding in E₄. AMMI bi-plot showed E₁ as the most informative environment for selecting widely adapted genotypes, while E₃ was highly representative but less discriminative. E₄ and E5 were discriminative but less representative. These findings highlight promising genotypes for the release of nutrient-rich rice varieties well-adapted to Chhattisgarh’s growing areas.