The meeting of the AG Maize in the GPZ jointly carried out with the Arbeitsgruppe Mais in the DMK and mainly organized by the Association des Selectioneurs Francais (main organizer Dr. Julie Fievet) in the newly built Campus AgroParisTech INRAE in Palaiseau, close to Paris. The meeting was held on May 23 – 24 and attended by a total of 88 participants from France (62), Germany (23) and other European countries (3), with a good mixture from industry and academia. Detailed access to the program and the abstracts of the presentations can be found on the webpage: https://www.billetweb.fr/section-mais-2023&src=agenda

In an introductory lecture on Carbon fluxes & Agriculture & Breeding, Nicolas Guilpart set the stage for the meeting by describing the challenges caused by climate change for future maize cultivation in Europe and possible contributions of different disciplines and interdisciplinary research for solutions.  

The first session focused on new biotic targeted traits. Ana Butron presented research on resistance to Fusarium ear rot (FER) in maize, exploring the genetic variability for resistance and identifying quantitative trait loci (QTL) associated with FER resistance. Julie Fievet discussed the genetic diversity of maize response to root symbiosis with arbuscular mycorrhizal fungi (AMF) and its implications for yield and nitrogen-related markers. Judith Legrand investigated the synchronization of life cycles between maize and maize stem borers, suggesting that early flowering inbred lines could be less susceptible to pests. Daniela Scheuermann focused on breeding for resistance to Northern corn leaf blight (NCLB), identifying major resistance loci and studying different haplotypes associated with resistance.

The second session explored new abiotic targeted traits. Christophe Maurel discussed the response of maize root hydraulic architecture to drought and its implications for water and solute transport. Fabio Guffanti investigated the genetic architecture of lateral root length in maize, highlighting the importance of these roots for nutrient uptake efficiency. Frank Hochholdinger examined the transcriptomic changes in maize roots in response to cold stress, identifying differentially expressed genes and the role of a transcription factor in root hair development. Catherine Giauffret focused on improving phosphorus-use efficiency in maize through breeding and genome-wide association mapping. Matthieu Reymond presented NIRS predictive equations for maize silage, adaptable to various growing conditions, by analyzing histological profiles of maize internodes to understand the distribution of lignified tissues in response to water deficit variations. Sandra Roller assessed the potential of breeding to improve P-use efficiency in maize, analyzing a diverse panel of maize lines and conducting multi-environment field trials. They found that there was a low overlap of quantitative trait loci (QTL) between different subpopulations and P treatments, providing insights into the genetic mechanisms underlying P uptake and use efficiency.

The third session centered around new diversity for maize breeding. Chris-Carolin Schön discussed the use of landraces and genome-based methods to broaden the genetic variation of maize breeding germplasm. Claude Welcker emphasized the need for novel breeding strategies to improve adaptive physiological traits related to water and temperature stress. Sebastian Urzinger identified QTL associated with early development and cold tolerance in maize landraces, highlighting the differential expression of candidate genes. Dimitri Sanchez presented tools for genetic selection and diversity management, emphasizing the importance of phenotype-based selection for potential diversity donors. Randall J. Wisser discussed the adaptability of tropical maize to novel environments and the genetic basis of response to phenotypic selection.

The fourth session focused on statistical methods and modeling for breeding schemes. Fabienne Henriot explored the use of envirotyping to understand environmental co-factors affecting plant growth and yield, providing insights for breeding decisions in the context of climate change. Susanne Groh discussed the use of reference sets of hybrids for pattern analysis and optimizing hybrid selection under different environmental conditions. Renaud Rincent highlighted the accuracy and advantages of phenomic selection as an alternative to genomic selection. Willem Molenaar presented novel approaches to increase the chromosome doubling rate in doubled haploid maize production. Tristan Mary-Huard discussed meta-analysis for investigating genotype-by-environment interactions and identifying QTLs with contrasted effects. François Tardieu concluded the conference by highlighting the challenges of breeding for both yield and adaptive traits in the context of climate change and the potential of integrating phenotyping and modeling for improved breeding strategies.

Overall, the conference presentations provided valuable insights and generated lively discussions into the genetic factors, environmental interactions, and innovative approaches in maize breeding for improved traits, disease resistance, and adaptation to climate change. 

Prof. Dr. Dr. h.c. Albrecht E. Melchinger