Exploring Genetic Resources to Increase Adaptation of Wheat to Climate Change

Abstract

The opinions expressed and arguments employed in this publication are the sole responsibility of the authors and do not necessarily refl ect those of the OECD or of the governments of its Member countries.The Special Session was sponsored by the OECD Co-operative Research Programme on Biological Resource Management for Sustainable Agricultural Systems, whose fi nancial support made it possible for most of the invited speakers to participate in the Special Session.Abstract The combined problems of climate change, population growth, and increased demands on a declining natural resource base force scientists to push crop performance to its limits. A powerful strategy is to explore genetic resources to identify promising material that can be used directly in breeding, for gene discovery, and to further understand the mechanisms of adaptation. Initially traits must be defi ned for stress targets using conceptual models, examples being better root systems to access subsoil deep water and the ability to store and remobilize water soluble carbohydrates from storage tissue. New sources of diversity for such traits can be found in collections such as the World Wheat Collection housed at CIMMYT; for example, Mexican landraces provide good sources of both of these traits. Being a 356 polyploid, wheat has a useful secondary gene pool that can be used to re-synthesize hexaploid wheat, while transgenic approaches remove all taxonomic limits to plant improvement. To effi ciently explore genetic resources, for crop improvement and to identify genetic and mechanistic bases, requires high throughput phenotyping approaches. For example, an airborne remote sensing platforms is used to determine spectral indices associated with temperature, water content, and pigment composition of leaves via thermal and multispectral imagery. Using the above approaches, best lines are used directly in pre-breeding to combine favorable combinations of traits and their alleles. These approaches have already delivered a new generation of drought adapted lines where cumulative gene action on yield is observed through strategic combination of stress adaptive traits many coming from landraces or products of wide crossing with wheat wild relatives.

A large nested association mapping population for breeding and quantitative trait locus mapping in Ethiopian durum wheat

“…With its intermediate tetraploid karyotype, durum wheat may be crossed with wild wheats to incorporate their haplotypes in a cultivated background (Avni et al ., ; Peleg et al ., ; Zhu et al ., ), supporting the availability of novel allelic diversity to wheat breeders. The AB genomes of durum wheat can be hybridized with wild species such as Aegilops tauschii , the donor of the D genome, to create synthetic hybrids targeting adaptive traits (Reynolds et al ., , ). Alleles coming from Triticum urartu , the wild donor of the A wheat genome that still grows in highly differentiated natural populations (Brunazzi et al ., ), have also been successfully introgressed in durum wheat amphiploids and lines (Alvarez et al ., ).…”

A strategy of ideotype development for heat‐tolerant wheat

“…However, heat tolerance is a complex trait that is highly influenced by the environment (Rebetzke, Condon, Farquhar, Appels, & Richards, ; Richards, Watt, & Rebetzke, ). The development of heat‐tolerant wheat cultivars is dependent upon access to genetic variation for tolerance to high temperatures (Cossani & Reynolds, ; Farooq, Bramley, Palta, & Siddique, ) and relevant phenotyping strategies that accurately predict field performance (Reynolds et al, ). Selection in the target environment is generally recommended, especially if these environments can be managed to reduce confounding factors (Richards et al, ; Trethowan, ).…”

Assessment of Vegetation Indices Derived by UAV Imagery for Durum Wheat Phenotyping under a Water Limited and Heat Stressed Mediterranean Environment

“…Their usefulness rely on the fact that they are non-destructive, non-invasive, fast and cost-efficient, well-correlated with agronomical and important physiological crop traits (Reynolds et al, 2015). …”