The data collected with harmonised formats have been shared in SolACE repository and used to parameterise crop models to evaluate wheat and potato production in Europe based on present and projected climate for various management scenarios. Experiments have been conducted with diverse germplasms for each crop to identify key root/microbiome traits and aboveground traits (or combinations of) contributing to crop tolerance to combined water and N/P limitations. Roots and shoots were phenotyped in controlled and field environments in large diversity panels for each crop. Smaller scale field trials for finer analyses of crop responses to combined stress and simulation with coupled crop / root architecture models have also been part of the strategy. Novel breeding strategies and tools have been designed to identify gene-derived markers for above- and belowground traits of crop adaptation to combined stress. Genomic selection (GS) models based on root traits were produced and tested in wheat. A participatory breeding strategy was applied in farmer communities in organically-grown durum wheat, and changes driven by combined stresses was studied in evolutionary breeding population. New F1 hybrids in diploid potato and bread wheat have been produced and tested for adaptation to combined stresses. A range of management practises have also been tested in controlled prior to field conditions: microbial strain combinations, crop rotations and durum wheat genotype mixtures. Numerous field trials have been performed across Europe to test these different management practices designed to improve stress resilience. Seven farmers’ networks have been set-up to test combinations of some of the above-mentioned novel genotypes and management practices on-farm with contrasting pedoclimatic conditions throughout Europe. Life Cycle Analysis (LCA) has been used to conduct a multicriteria assessment of the innovations tested within these networks. Stakeholder workshops were held to collect feedbacks on tested innovations.
Crop modelling showed a wide diversity of crop responses to climate change, either negative in Southern and Eastern regions of Europe, or rather positive in other areas: there, yield improvement due to increased CO2 and temperature may indeed occur, assuming no other stress would occur. Experiments and model simulations with diverse wheat and potato germplasms showed under which circumstances crop/root/microbiome traits (or combinations of) contributed to crop tolerance to combined water and N/P stress. Significant diversity and plasticity of root traits was found, making SolACE efforts a first step forward, in spite of the difficulties to isolate traits supporting crop performance. Deep rooting emerged as an essential trait for drought adaptation and nutrient acquisition at depth. Root-trait based GS models were set up and validated for improving wheat yield adaptation under multiple stresses. Experimental F1-hybrid produced in potato and bread wheat proved quite efficient to face multiple stresses in field conditions. In durum wheat, participatory breeding strategy led to new populations evolved from a genetically diverse population, involving organic farmers in Hungary and Italy. In addition to these breeding strategies and products, the tested management innovations proved more or less efficient under combined drought and N/P limitations. While using legumes as precrop or reduced tillage revealed often efficient, durum wheat genotype mixtures and formulated microbial consortia inoculants proved promising, although their effect under field conditions was not always significant. Engagement of farmers with the project has raised interest and enthusiasm for most of the tested innovations. On-farm experiments highlighted the potential of grain legumes in rotations to reduce the C footprint of cereals and improve the economic margin to farmers, based on LCA. On-farm experiments showed inconsistent results for microbial inoculants and experimental potato hybrids, but farmers were keen to further assess such innovations over a larger number of trialling years. SolACE partners engaged stakeholders beyond farmers through a series of events and modes of interaction. Practice abstracts, videos, training materials, specialized press and newsletters, and policy briefs have been made available on the SolACE website and community on Zenodo. Further exploitation of some of the findings is currently being considered for the work conducted on microbial inoculants, F1-hybrids of bread wheat and potato, as well as for durum wheat populations derived from the participatory approach.
