Competition and its consequences for selection in barley breeding

C.J.T. Spitters

Research output: Thesisinternal PhD, WU


The influence of competition is discussed and quantified for unselected bulk propagation, single-plant selection and yield testing of progenies in row plots. A mathematical model is introduced that defines the influence of intergenotypic competition and density of stand on the response to selection. The model is verified with the results of mixtures and monocultures of barley varieties. Intergenotypic competition usually increases the genetic variance considerably, but hardly affects the environmental variance. Selection for yield in a segregating population, i.e. in a mixture, results in a correlated response for monoculture yield.<br/>Delaying selection for yield until the late generations of a segregating population is not handicapped by competition and natural selection. Methods to account for competition in single-plant selection and in yield testing of progenies in row plots are discus-<br/>sed. The selection response is independent of the spacing provided that certain prerequisites are satisfied. Alternating the plants or rows with those of a standard variety is of no use in reducing the competitional bias. Given the present nursery equipment,<br/>3-row plots with all three rows considered in selection for yield, seem the most suitable type of microplot.<p/>
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • de Wit, C.T., Promotor
  • Sneep, J., Co-promotor, External person
Award date12 Dec 1979
Place of PublicationWageningen
Print ISBNs9789022007129
Publication statusPublished - 1979


  • barley
  • hordeum vulgare
  • plant breeding
  • cum laude


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