Trends in Varietal Diversity of Main Staple Crops in Asia and Africa and Implications for Sustainable Food Systems

Marcel Gatto,Merideth Bonierbale,Guy Hareau,Ricardo Labarta,Stef De Haan,Alice Laborte

doi:10.3389/fsufs.2021.626714

Abstract

Crop species and varietal diversity on farm have the potential to trigger multiple regulating and provisioning ecosystem services. The latter is commonly assessed through targeted studies covering a select number of geographies and crop species, precluding comparisons across crops and at scale. This study draws on a large dataset on the varietal release dynamics for 11 major food crops in 44 countries of Asia and Africa to assess trends in diversity across crops and regions with a 50-year perspective. Our results show an increasing reduction of crop varietal diversity linked to the spatial displacement of traditional landraces. This trend occurs at a faster rate in Asia than in Africa. So-called mega varieties tend to increasingly dominate agricultural landscapes, adding to spatial homogeneity. We further found a negative association between varietal richness and its relative abundance, challenging the relationship between crop improvement and varietal diversity. Our results show that among cereal, pulse, and root and tuber crops, varietal diversity is lowest for cereals in Asia and highest for root and tubers in Africa. The analysis contributes new information useful to prioritize crops for which increasing varietal diversity may lead to more sustainable food systems.

Highlights

Agricultural diversity can be beneficial for environmental health, resilience, and food production (Wolfe, 2000; Frison et al, 2011)
Climate change will drive extreme weather events and the range expansion of infectious plant diseases and pests (Anderson et al, 2004; Elad and Pertot, 2014; Bebber, 2015), which suggests that managing genetic diversity within crop species and keeping crop varietal diversity a part of the agricultural landscape can be an increasingly important focus to enhance food system resilience, i.e., the capacity to respond and recover from shocks (Frison et al, 2011)
Until the 2000s, cumulative total varietal releases for all crops amounted to 98 varieties per 100,000 hectares in Asia and 70 varieties per 100,000 hectares in Africa (Figure 3)

Summary

Introduction

Agricultural diversity can be beneficial for environmental health, resilience, and food production (Wolfe, 2000; Frison et al, 2011). In this context, crop species diversity and intraspecific diversity are often identified as resulting in both nutrition security and ecological resilience (De Haan et al, 2010; Lin, 2011; Jones, 2017; Reiss and Drinkwater, 2018). Climate change will drive extreme weather events and the range expansion of infectious plant diseases and pests (Anderson et al, 2004; Elad and Pertot, 2014; Bebber, 2015), which suggests that managing genetic diversity within crop species and keeping crop varietal diversity a part of the agricultural landscape can be an increasingly important focus to enhance food system resilience, i.e., the capacity to respond and recover from shocks (Frison et al, 2011)

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Discussion

Conclusion