Abstract

Rainfed lowland rice productivity in Côte d’Ivoire is severely constrained by iron toxicity and Rice Yellow Mottle Virus (RYMV). This study aimed to identify high-performing lines combining high paddy yield with tolerance or resistance to both stresses. Forty-four African rice lines were evaluated through field screening under an iron toxicity hotspot, greenhouse RYMV screening and yield trials in an alpha-lattice (5 × 9) with three replications. Agro-morphological traits were analyzed using mixed models, and selection indices were derived from Best Linear Unbiased Predictions (BLUPs) weighted by breeding objectives. Results indicated 18% of lines were partially resistant to RYMV, 66% tolerant and 95% moderately tolerant to iron toxicity. Principal Component Analysis (PCA) and hierarchical clustering grouped genotypes into three clusters, with the high-yielding cluster showing substantial variability in yield components, facilitating multi-trait selection. Four lines (ART1475-B-B-B-1-3-1, ART311-B-78-1-7, ART1555-B-B-4-4 and ART1555-B-B-24-4) met breeding objectives, achieving 16-33% higher yields than WITA 9 and desirable phenological and morphological traits. Eight elite lines (ART1475-B-B-B-1-3-1, ART1567-B-B-2-4, ART1553-B-B-3-4, ART1553-B-B-12-4, ART1555-B-B-24-4, ART1555-B-B-4-4, ART311-B-78-1-7 and ART1544-B-B-12-4) combining superior selection index values with tolerance to both stresses produced 2.18-2.69 t ha-1 (7-33% yield advantage). The four selected lines will be advanced for on-farm validation, while the eight top-performing lines, identified based on the selection index, will be utilized in breeding programs to enhance stress tolerance and yield potential of locally adapted rice varieties.