Assessing the effects of stay-green alleles in elite sorghum material from West Africa

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Résumé

Understanding the effects of stay-green (Stg) alleles within elite sorghum germplasm from West and Central Africa is necessary to leverage the benefits of the Stg trait in the regional context. To reach this objective, the effects of introgressed Stg alleles were evaluated in populations derived from two elite varieties in the INERA breeding programme across three trials conducted under natural water stress and one trial under continuous irrigation until physiological maturity based on 70 families corresponding either to BC1F4:5 or BC2F2:3 generations. Markers allowing to follow the Stg alleles in the two populations were developed. According to previous studies, variable effects of the Stg alleles were detected depending on the populations and environment considered. A majority of negative effects of the Stg alleles on grain yield were observed. Nevertheless, families harbouring delayed senescence dynamics were identified calling for their accurate characterisation in well controlled conditions. The results indicate that Stg is a highly complex trait to characterise that requires well defined experimental conditions. There should be a clear definition of the future most frequent scenarios in West and Central Africa regions to be able to refine the role that Stg could play.

Mots-clés

Sorghum, stay-green alleles, introgression, drought tolerance, breeding, West and Central Africa