Stability of grain zinc concentrations across lowland rice environments favors zinc biofortification breeding

Rakotondramanana Mbolatantely, Wissuwa Matthias, Ramanankaja Landiarimisa, Razafimbelo Tantely, Stangoulis James, Grenier Cécile. 2024. Stability of grain zinc concentrations across lowland rice environments favors zinc biofortification breeding. Frontiers in Plant Science, 15:1293831, 16 p.

Résumé : Introduction: One-third of the human population consumes insufficient zinc (Zn) to sustain a healthy life. Zn deficiency can be relieved by increasing the Zn concentration ([Zn]) in staple food crops through biofortification breeding. Rice is a poor source of Zn, and in countries predominantly relying on rice without sufficient dietary diversification, such as Madagascar, Zn biofortification is a priority. Methods: Multi-environmental trials were performed in Madagascar over two years, 2019 and 2020, to screen a total of 28 genotypes including local and imported germplasm. The trials were conducted in the highlands of Ankazomiriotra, Anjiro, and Behenji and in Morovoay, a location representative of the coastal ecosystem. Contributions of genotype (G), environment (E), and G by E interactions (GEIs) were investigated. Result: The grain [Zn] of local Malagasy rice varieties was similar to the internationally established grain [Zn] baseline of 18–20 μg/g for brown rice. While several imported breeding lines reached 50% of our breeding target set at +12 μg/g, only few met farmers' appreciation criteria. Levels of grain [Zn] were stable across E. The G effects accounted for a main fraction of the variation, 76% to 83% of the variation for year 1 and year 2 trials, respectively, while GEI effects were comparatively small, contributing 23% to 9%. This contrasted with dominant E and GEI effects for grain yield. Our results indicate that local varieties tested contained insufficient Zn to alleviate Zn malnutrition, and developing new Zn-biofortified varieties should therefore be a priority. GGE analysis did not distinguish mega-environments for grain [Zn], whereas at least three mega-environments existed for grain yield, differentiated by the presence of limiting environmental conditions and responsiveness to improved soil fertility. Discussion: Our main conclusion reveals that grain [Zn] seems to be under strong genetic control in the agro-climatic conditions of Madagascar. We could identify several interesting genotypes as potential donors for the breeding program, among those BF156, with a relatively stable grain [Zn] (AMMI stability value (ASV) = 0.89) reaching our target (>26 μg/g). While selection for grain yield, general adaptation, and farmers' appreciation would have to rely on multi-environment testing, selection for grain [Zn] could be centralized in earlier generations.

Mots-clés Agrovoc : Oryza sativa, génotype, variété, zinc, grain, amélioration génétique, essai de variété, méthode d'essai, riz, biofortification, facteur climatique, intéraction génotype environnement, sélection, fertilisation

Mots-clés géographiques Agrovoc : Madagascar

Mots-clés libres : Oryza sativa, Baseline zinc concentration, Genotype by environment interactions, Grain yield, Zn biofortification breeding targets, Stability

Agences de financement hors UE : HarvestPlus, Consortium of International Agricultural Research Centers, Japan Science and Technology Agency

Projets sur financement : (USA) Rice biofortification in Madagascar

Auteurs et affiliations

• Rakotondramanana Mbolatantely, FOFIFA (MDG)
• Wissuwa Matthias, JIRCAS (JPN) - auteur correspondant
• Ramanankaja Landiarimisa, Université d'Antananarivo (MDG)
• Razafimbelo Tantely, Université d'Antananarivo (MDG)
• Stangoulis James, Flinders University (AUS)
• Grenier Cécile, CIRAD-BIOS-UMR AGAP (FRA) ORCID: 0000-0001-5390-8344 - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/608361/)

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