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Adaptation and yield stability of three cereal species in semiarid and subhumid regions of Tunisia Volume 10, issue 4, Décembre 1999

Authors
Département d’amélioration des plantes, Laboratoire d’amélioration des céréales, ESA Kef, 7119, Le Kef, Tunisie.
  • Page(s) : 273-9
  • Published in: 2000

The success of a new cereal variety depends upon its yield and adaptation potential. Genotypes with high stable yield are highly esteemed by both farmers and breeders. The present study was aimed at analysing the yield stability and adaptation of several cultivars of three different cereal species (durum wheat, bread wheat, and barley) that were tested in subhumid and semiarid environments in Tunisia through many growing seasons. The analyses of variance of grain yield revealed significant yield differences between the cultivars and species tested, and genotype x environment interactions were also noted. Regression equations were drawn up for yields of each variety at each site relative to the mean yield of all varieties at all sites. Regression coefficients (b values) were used as measurements of adaptation, and coefficients of determination (R2) were used to assess stability. Consideration of these parameters along with the nature of cultivar/yield relationships at each site and mean cultivar yield at the different sites revealed three types of cultivars, i.e. those specifically adapted to poor environments, those specifically adapted to favourable environements, and those with a broad adaptation potential that are able to take advantage of optimal environments.