Rakotondramanana Mbolatantely, Wissuwa Matthias, Ramanankaja Landiarimisa, Razafimbelo Tantely, Stangoulis James, Grenier Cécile
Rice Research Department, The National Center for Applied Research on Rural Development (FOFIFA), Antananarivo, Madagascar.
Crop, Livestock and Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Japan.
Front Plant Sci. 2024 Feb 13;15:1293831. doi: 10.3389/fpls.2024.1293831. eCollection 2024.
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.
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.
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.
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.
全球三分之一的人口锌（Zn）摄入量不足，无法维持健康生活。通过生物强化育种提高主食作物中的锌浓度（[Zn]），可缓解锌缺乏问题。水稻是锌的不良来源，在主要依赖水稻且饮食多样化不足的国家，如马达加斯加，锌生物强化是当务之急。
2019年和2020年在马达加斯加进行了为期两年的多环境试验，以筛选包括当地和进口种质在内的共28个基因型。试验在安卡佐米约特拉、安吉罗和贝亨吉的高地以及代表沿海生态系统的莫罗瓦伊进行。研究了基因型（G）、环境（E）以及G与E的互作（GEIs）的贡献。
马达加斯加当地水稻品种的籽粒[Zn]与国际公认的糙米籽粒[Zn]基线18 - 20μg/g相似。虽然一些进口育种系达到了我们设定的+12μg/g育种目标的50%，但只有少数符合农民的评价标准。籽粒[Zn]水平在不同环境中较为稳定。G效应占变异的主要部分，在第1年和第2年试验中分别占变异的76%至83%，而GEI效应相对较小，则占23%至9%。这与籽粒产量中占主导的E和GEI效应形成对比。我们的结果表明，所测试的当地品种含锌量不足以缓解锌营养不良，因此培育新的锌生物强化品种应是优先事项。GGE分析未区分出籽粒[Zn]的大环境，而籽粒产量至少存在三个大环境，其区别在于存在限制环境条件以及对改善土壤肥力的响应。
我们的主要结论表明，在马达加斯加的农业气候条件下，籽粒[Zn]似乎受强大的遗传控制。我们可以鉴定出几个有趣的基因型作为育种计划的潜在供体，其中BF156的籽粒[Zn]相对稳定（AMMI稳定性值（ASV）= 0.89），达到了我们的目标（>26μg/g）。虽然对籽粒产量、一般适应性和农民评价的选择必须依赖多环境测试，但对籽粒[Zn]的选择可以集中在较早世代。
