Consistent yield performance of rice genotypes grown under irrigated conditions in wet and dry seasons in West Africa

Source Agritrop Cirad (https://agritrop.cirad.fr/609063/) * Autres projets (id;sigle;titre): ;;(FRA) Systèmes agricoles durables et diversifiés à base de riz//

International audience

إنجليزي. Context: Rice double cropping in irrigated systems is essential for increasing rice production and ensuring food security in West Africa. Rice breeding programs must develop genotypes that are expected to perform well either across wet and dry seasons or for a specific season. Objective: This study aimed to investigate the consistency of genotypic performance across two seasons and identify high-yielding genotypes and their characteristics. Methods: 50 diverse genotypes were grown under irrigated conditions in wet and dry seasons at three sites in West Africa (M'bé in Côte d'Ivoire, and Fanaye and Ndiaye in Senegal) for three years (2018–2020). Results: Mean grain yield across all genotypes was higher in dry season in Fanaye (593 vs. 495 g/m2) and Ndiaye (737 vs. 415 g/m2) than in wet season, but the same for the two seasons in M'bé (512 vs. 507 g/m2). The consistency of genotypic performance across wet and dry seasons was the highest in M'bé (r = 0.88, P < 0.01), followed by Fanaye (r = 0.71, P < 0.01), and lowest in Ndiaye (r = 0.49, P < 0.01). Thus, correlations for yields between two seasons becomes poorer as difference in yield level between two seasons becomes larger. Two (NSIC Rc240 and Giza 178) and one (MG 2::IRGC 79837-1) genotypes from other regions were identified for high yield in both seasons in Côte d'Ivoire and Senegal, respectively. High-yielding genotypes were characterized by large aboveground biomass and high harvest index in both seasons in all three sites. Grain yield was positively correlated with days to heading and number of grains per panicle in both seasons in M'bé and Fanaye. In Ndiaye, none of the yield components was consistently related to grain yield across two seasons. Conclusions: It is possible for rice breeding programs to develop and identify genotypes that are expected to perform well in two seasons. High-yielding genotypes identified in this study can be used as donors for improving rice productivity in West Africa. Implications: Field experiments were conducted in three sites in two countries only, and further effort is needed to evaluate consistency of genotypic performance across diverse agro-ecological zones in West Africa.