David J. Bertioli, Josh Clevenger, Ignacio J. Godoy, H. T. Stalker, Shona Wood, Joáo F. Santos, Carolina Ballén-Taborda, Brian Abernathy, Vania Azevedo, Jacqueline Campbell, Carolina Chavarro, Ye Chu, Andrew D. Farmer, Daniel Fonceka, Dongying Gao, Jane Grimwood, Neil Halpin, Walid Korani, Marcos D. Michelotto, Peggy Ozias-Akins, Justin Vaughn, Ramey Youngblood, Marcio C. Moretzsohn, Graeme C. Wright, Scott A. Jackson, Steven B. Cannon, Brian E. Scheffler, and Soraya C. M. Leal-Bertioli

PNAS September 21, 2021 118 (38) e2104899118

Significance

A great challenge for humanity is feeding its growing population while minimizing ecosystem damage and climate change. Here, we uncover the global benefits arising from the introduction of one wild species accession to peanut-breeding programs decades ago. This work emphasizes the importance of biodiversity to crop improvement: peanut cultivars with genetics from this wild accession provided improved food security and reduced use of fungicide sprays. However, this study also highlights the perilous consequences of changes in legal frameworks and attitudes concerning biodiversity. These changes have greatly reduced the botanical collections, seed exchanges, and international collaborations which are essential for the continued diversification of crop genetics and, consequently, the long-term resilience of crops against evolving pests and pathogens and changing climate.

Abstract

The narrow genetics of most crops is a fundamental vulnerability to food security. This makes wild crop relatives a strategic resource of genetic diversity that can be used for crop improvement and adaptation to new agricultural challenges. Here, we uncover the contribution of one wild species accession, Arachis cardenasii GKP 10017, to the peanut crop (Arachis hypogaea) that was initiated by complex hybridizations in the 1960s and propagated by international seed exchange. However, until this study, the global scale of the dispersal of genetic contributions from this wild accession had been obscured by the multiple germplasm transfers, breeding cycles, and unrecorded genetic mixing between lineages that had occurred over the years. By genetic analysis and pedigree research, we identified A. cardenasii–enhanced, disease-resistant cultivars in Africa, Asia, Oceania, and the Americas. These cultivars provide widespread improved food security and environmental and economic benefits. This study emphasizes the importance of wild species and collaborative networks of international expertise for crop improvement. However, it also highlights the consequences of the implementation of a patchwork of restrictive national laws and sea changes in attitudes regarding germplasm that followed in the wake of the Convention on Biological Diversity. Today, the botanical collections and multiple seed exchanges which enable benefits such as those revealed by this study are drastically reduced. The research reported here underscores the vital importance of ready access to germplasm in ensuring long-term world food security.

See https://www.pnas.org/content/118/38/e2104899118

Figure 1: Visualization of introgressed chromosome segments from the wild species A. cardenasii in 142 samples comprising 82 registered peanut lines and cultivars from around the world. (A) Overview of chromosomes from A01 to A10. Each peanut genotype is represented as a vertical column, with introgressed wild species chromosome segments in blue. The common origin of the vast majority of peanut introgressions is indicated by the extreme similarity of introgression patterns, which have dispersed from the US, to India, to the rest of the world. Chromosome size is proportional to number of polymorphic markers and is not to scale. QTL regions for disease and pest resistance are indicated to the Right of the panel (LLS, late leaf spot; RKN, root-knot nematode). (B and C) Representations of fine-scale recombination between A and B subgenomes at chromosome terminals which have the most common introgressions: the uppermost region of A. hypogaea chromosome 02 and the lower end of 13, respectively. B genome alleles being represented with black background and A genome alleles with white background. Lines with introgressions have patterns that are very similar to each other, and distinct from all peanuts of pure pedigree and its wild counterpart A. monticola.