Genetics and ecophysiology studies of maize adaptation to abiotic stresses and heterosis

WP leader: Catherine Giauffret (UR AgroImpact)
Partners involved: INRA UMR GQE, UMR LEPSE, UMR AGAP, UR AgroImpact, UMR IJPB, UMR BFP,
Arvalis, Biogemma, Maïsadour Semences, Euralis Semences, Limagrain, Caussade Semences, RAGT 2n

Context and objectives:

Heterosis, i.e. the advantage of hybrids over their parental inbred lines, and environmental adaptation are two key features in modern maize breeding. Environmental-friendly cultivation of maize in Europe requires mainly tolerance to three abiotic stresses: low temperature to allow earlier sowing dates, water and nitrogen deficiency. The variability of climatic sequences and cropping practices tends to mask the genetic determinism of tolerance and limits the efficiency of selection. Assembling tolerance to different stresses by crossing complementary inbreds is probably one of the most interesting characteristic of heterosis, as illustrated by the major success of hybrids between US dent lines and European flint lines for maize cultivation in Northern Europe.

The objectives of WP5 are therefore 1) to provide a better integrated view of maize responses for a broad variety of stresses, 2) to identify loci and alleles involved in stress tolerance, 3) to better understand the mechanisms underlying heterosis and their relative contributions, 4) to provide predicting equations of breeding values to be used in WP8.

WP5 :

• Addresses genetics of adaptation traits of interest using panels, genotyping data, reference methods /models developed in WP4 to (i) identify QTL of major effect and their favorable alleles and (ii) calibrate polygenic prediction formula to be used in breeding programs.
• Conducts phenotyping of these panels through a combination of generic field experiments in contrasted environmental conditions, evaluation with specific protocols in the field, and use of advanced platforms (Lemnatech platform of P2).
• Analyzes proteome and metabolome of these panels to identify diagnostic molecules identifies QTL.

Deliverables

D5.1: List of key bio-markers (metabolites, proteins, etc…) and traits related to environmental adaptation (M48) and heterosis (M60).

D5.2: Genomic regions/alleles controlling proteins, metabolites and key plant traits variation in response to water deficit (M60).

D5.3: Genomic regions/alleles controlling metabolites and plant traits variation in response to low temperature in the dent (M48) and flint panels (M96).

D5.4: Genomic regions/alleles controlling NUE physiological traits and yield variations in the dent (M48) and flint panels (M96).