Science et changements planétaires / Sécheresse


Carbon isotope discrimination and durum wheat yieldsin the Sétif high plains of Algeria Volume 12, issue 1, Mars 2001


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Université Ferhat-Abbas, Département des sciences biologiques, 19000 Sétif, Algérie.
  • Page(s) : 37-43
  • Published in: 2001

Improving crop yields in drought conditions is an important objective for plant breeders in the Mediterranean area. Carbon isotope discrimination (delta) was proposed some years ago as a predictive criterion for water-use efficiency (WUE) and yield under drought. The advantages of this criterion in breeding programs are: i) its integrative value; ii) its close relationship with yield; iii) its high variability and heritability values, and; iv) the ease of sample preparation and analysis automation. The main aims of the present study were to examine genotype x environment interactions for grain yield and to analyse the relationship between yield stability and carbon isotope discrimination in different organs (grain, flag leaf, peduncle, rachis and awn). The study was carried out in six drought-prone environments on the Sétif high plains (eastern Algeria) on 15 durum wheat varieties (Algerian landraces and improved varieties). For mean delta values, the different organs were ranked in the following order: flag leaf, awns and rachis, peduncle and grain. Carbon discrimination for grain, flag leaf and peduncle (deltaG, deltaF and deltaC, respectively) were significantly correlated with yield. However, the closest correlations were noted for deltaG. Variations in this trait were mainly explained by variation in carbon isotope discriminations for flag leaf (deltaF) and peduncle (deltaC). Flag leaf delta was also found to have the main relative contribution to carbon isotope discrimination for grain. Six varieties were also tested in five other environments. Since low genetoype x environment interactions were noted for yield in the six environments, deltaG, deltaF and deltaC were also correlated with yield in most other environments considered. The variety that yielded best in most environments (cv Waha) was found to have the highest deltaG and deltaF values and the highest relative contribution of F to deltaG. The potential advantage of delta as a breeding criterion for drought tolerance and yield stability and the usefulness of assessing it in different organs are discussed.