Rod J. Snowdon, Benjamin Wittkop, Tsu-Wei Chen & Andreas Stahl

Theoretical and Applied Genetics June 2021; vol. 134:1613–1623.

Breeding is a long-term process. Conventional selection procedures consider plant performance in multiple environments over many years and are thus well-suited for adaptation to climate change. However, modern breeding technologies can help to accelerate the incremental accumulation of positive alleles for “invisible” physiological traits underlying climate adaptation.

Major global crops in high-yielding, temperate cropping regions are facing increasing threats from the impact of climate change, particularly from drought and heat at critical developmental timepoints during the crop lifecycle. Research to address this concern is frequently focused on attempts to identify exotic genetic diversity showing pronounced stress tolerance or avoidance, to elucidate and introgress the responsible genetic factors or to discover underlying genes as a basis for targeted genetic modification. Although such approaches are occasionally successful in imparting a positive effect on performance in specific stress environments, for example through modulation of root depth, major-gene modifications of plant architecture or function tend to be highly context-dependent. In contrast, long-term genetic gain through conventional breeding has incrementally increased yields of modern crops through accumulation of beneficial, small-effect variants which also confer yield stability via stress adaptation. Here we reflect on retrospective breeding progress in major crops and the impact of long-term, conventional breeding on climate adaptation and yield stability under abiotic stress constraints. Looking forward, we outline how new approaches might complement conventional breeding to maintain and accelerate breeding progress, despite the challenges of climate change, as a prerequisite to sustainable future crop productivity.

See: https://link.springer.com/article/10.1007/s00122-020-03729-3

Figure 1: Climate change can potentially have very different impacts on crop performance depending on the time-point and duration of drought events and whether drought stress occurs in combination with heat stress or alone. Depending on the type and intensity of stress, different genetically determined responses may be more beneficial for the performance of a cultivar. This means there is no single, simple per se solution for breeders to overcome the potential impacts of drought stress caused by climate change. Selection for performance and yield stability under the expected stress scenarios that occur commonly in a particular target region may be the best way to maintain crop performance while mitigating risks. Yield selection in target environments also improves complex stress response traits and yield stability.