Pujar Mahesh, Govindaraj Mahalingam, Gangaprasad S, Kanatti Anand, Gowda T H, Dushyantha Kumar B M, Satish K M
International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India.
Department of Genetics and Plant Breeding, University of Agricultural and Horticultural Sciences, Shimoga, Shivamogga, India.
Front Plant Sci. 2022 Jan 28;12:693680. doi: 10.3389/fpls.2021.693680. eCollection 2021.
Pearl millet [ (L.) R. Br.] is a climate-resilient dryland cereal that has been identified as a potential staple food crop that can contribute to alleviating micronutrient malnutrition, particularly with respect to grain iron (Fe) and zinc (Zn) contents, in Sub-Saharan Africa and India. In this regard, an understanding of the inheritance pattern of genes involved in Fe and Zn contents is vital for devising appropriate breeding methods to genetically enhance their levels in grains. In this study, we aimed to determine the genetic effects underlying such inheritance and their interactions based on the generation mean analyses. Four experimental crosses and their six generations (P, P, F, BCP, BCP, and F) were independently evaluated in a compact family block design in 2017 rainy and 2018 summer seasons. ANOVA revealed highly significant mean squares ( < 0.01) among different generations for grain Fe and Zn contents. Six-parameter generation mean analyses revealed a predominance of additive genetic effect and a significant ( < 0.05) additive × dominant interaction for the grain Fe content. The additive genetic effect for the grain Zn content was also highly significant ( < 0.01). However, interaction effects contributed minimally with respect to most of the crosses for the grain Zn content and hence we assume that a simple digenic inheritance pattern holds true for it. Furthermore, we established that narrow-sense heritability was high for the grain Fe content (>61.78%), whereas it was low to moderate for the grain Zn content (30.60-59.04%). The lack of superior parent heterosis coupled with non-significant inbreeding depression for Fe and Zn contents in grains further confirmed the predominance of an additive genetic effect. These findings will contribute to strategizing a comprehensive breeding method to exploit the available variability of grain Fe and Zn contents for the development of biofortified hybrids of pearl millet.
珍珠粟[（L.）R. Br.]是一种适应气候变化的旱地谷物，已被确定为一种潜在的主食作物，有助于缓解撒哈拉以南非洲和印度的微量营养素营养不良问题，特别是在谷物铁（Fe）和锌（Zn）含量方面。在这方面，了解参与铁和锌含量的基因的遗传模式对于设计适当的育种方法以从基因上提高其在谷物中的含量至关重要。在本研究中，我们旨在基于世代均值分析确定这种遗传背后的遗传效应及其相互作用。2017年雨季和2018年夏季，在紧凑的家系区组设计中对四个实验杂交组合及其六个世代（P₁、P₂、F₁、BCP₁、BCP₂和F₂）进行了独立评估。方差分析显示，不同世代间谷物铁和锌含量的均方极显著（P < 0.01）。六参数世代均值分析表明，谷物铁含量以加性遗传效应为主，且存在显著（P < 0.05）的加性×显性互作。谷物锌含量的加性遗传效应也极显著（P < 0.01）。然而，对于大多数杂交组合，互作效应在谷物锌含量方面贡献极小，因此我们认为其符合简单的双基因遗传模式。此外，我们确定谷物铁含量的狭义遗传力较高（>61.78%），而谷物锌含量的狭义遗传力则为低到中等（30.60 - 59.04%）。谷物中铁和锌含量缺乏优良亲本杂种优势以及不显著的近交衰退进一步证实了加性遗传效应的主导地位。这些发现将有助于制定一种综合育种方法，以利用谷物铁和锌含量的现有变异性来培育珍珠粟的生物强化杂交种。
