Adaptation of sorghum: characterisation of genotypic flowering responses to temperature and photoperiod

Craufurd P.Q., Mahalakshmi V., Bidinger F.R., Mukuru S.Z., Chantereau Jacques, Omanga P.A., Qi A., Roberts E.H., Ellis R.H., Summerfield R.J., Hammer G.L.. 1999. Adaptation of sorghum: characterisation of genotypic flowering responses to temperature and photoperiod. Theoretical and Applied Genetics, 99 : 900-911.

Résumé : Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop grown in a wide range of tropical and temperate environments. This study was conducted to characterise the photothermal flowering responses of sorghum genotypes and to examine relationships between photothermal characteristics and environment of origin in order to better understand the phenological basis of adaptation to environment in sorghum. Twentyfour germplasm accessions and one hybrid from 24 major sorghum-growing areas were grown in a wide range of environments varying in temperature and photoperiod in India, Kenya and Mali between 1992 and 1995. Times from sowing to flowering (f) were recorded, and the responsiveness of 1/f to temperature and photoperiod was quantified using photothermal models. Times from sowing to flowering were accurately predicted in a wide range of environments using a multiplicative rate photothermal model. Significant variation in the minimum time to flower (Fm) and photoperiod sensitivity (critical photoperiod, Pc, and photoperiod-sensitivity slope, Ps) was observed among the genotypes; in contrast there was little variation in base temperature (Tb). Adaptation of sorghum to the diverse environments in which it is grown was largely determined by photoperiod sensitivity and minimum time to flower; photoperiod sensitivity determines broad adaptation to latitude (daylength), while variation in the minimum time to flower determines specific adaptation within smaller ranges of latitude, e.g. within the humid and sub-humid tropics.

Mots-clés Agrovoc : Sorghum bicolor, génotype, température, photopériodicité, floraison, ensemencement, facteur du milieu, modèle

Mots-clés géographiques Agrovoc : Inde, Kenya, Mali

Classification Agris : F62 - Physiologie végétale - Croissance et développement

Auteurs et affiliations

• Craufurd P.Q., University of Reading (GBR)
• Mahalakshmi V., ICRISAT (IND)
• Bidinger F.R., ICRISAT (IND)
• Mukuru S.Z., ICRISAT (KEN)
• Chantereau Jacques, CIRAD-CA-CALIM (FRA)
• Omanga P.A.
• Qi A., University of Reading (GBR)
• Roberts E.H., University of Reading (GBR)
• Ellis R.H., University of Reading (GBR)
• Summerfield R.J., University of Reading (GBR)
• Hammer G.L., CSIRO (AUS)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/475609/)

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