Abstract
Pearl millet [Pennisetum glaucum (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 (P1, P2, F1, BCP1, BCP2, and F2) were independently evaluated in a compact family block design in 2017 rainy and 2018 summer seasons. ANOVA revealed highly significant mean squares (p < 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 (p < 0.05) additive × dominant interaction for the grain Fe content. The additive genetic effect for the grain Zn content was also highly significant (p < 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.
Highlights
With the exception of additive × dominant effects for cross-III in E1, we found that the epistatic interaction effects for the grain Zn content were non-significant for crosses II and III in E1 and E2, wherein their magnitudes were relatively lower than those of the respective additive genetic effects
We found that the interaction effects associated with grain Zn content, such as additive × dominant and dominant × dominant, were consistently significant in both E1 and E2 in the case of cross-IV, thereby further confirming that these interaction effects are cross-specific
We found that only cross-IV in E1 showed a significant dominant genetic effect along with a dominant × dominant interaction effect, which was in the opposite direction, indicating that the grain Zn content is governed by duplicate epistasis
Summary
Pearl millet is naturally a rich source of grain iron (Fe) and zinc (Zn) contents, which play a macro-role in human health. Deficiencies in one or multiple essential nutrients can lead to micronutrient-associated malnutrition, known as “hidden hunger” (UNICEF, 1990) with an excess of 2 billion people worldwide suffering from micronutrient deficiencies, primarily in developing countries such as Africa and India (World Health Organization [WHO], 2019). Within these populations, anemia has been found to be alarmingly high, among pregnant women (40%) and children (42%) below 5 years of age (WHO). Both anemia and stunting are, to a large extent, consequences of diet deficiency in Fe and Zn (Caulfield et al, 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
