Genetic evidence for differential selection of grain and embryo weight during wheat evolution under domestication

Guy Golan, Adi Oksenberg, Zvi Peleg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Wheat is one of the Neolithic founder crops domesticated ∼10 500 years ago. Following the domestication episode, its evolution under domestication has resulted in various genetic modifications. Grain weight, embryo weight, and the interaction between those factors were examined among domesticated durum wheat and its direct progenitor, wild emmer wheat. Experimental data show that grain weight has increased over the course of wheat evolution without any parallel change in embryo weight, resulting in a significantly reduced (30%) embryo weight/grain weight ratio in domesticated wheat. The genetic factors associated with these modifications were further investigated using a population of recombinant inbred substitution lines that segregated for chromosome 2A. A cluster of loci affecting grain weight and shape was identified on the long arm of chromosome 2AL. Interestingly, a novel locus controlling embryo weight was mapped on chromosome 2AS, on which the wild emmer allele promotes heavier embryos and greater seedling vigour. To the best of our knowledge, this is the first report of a QTL for embryo weight in wheat. The results suggest a differential selection of grain and embryo weight during the evolution of domesticated wheat. It is argued that conscious selection by early farmers favouring larger grains and smaller embryos appears to have resulted in a significant change in endosperm weight/embryo weight ratio in the domesticated wheat. Exposing the genetic factors associated with endosperm and embryo size improves our understanding of the evolutionary dynamics of wheat under domestication and is likely to be useful for future wheat-breeding efforts.

Original languageAmerican English
Pages (from-to)5703-5711
Number of pages9
JournalJournal of Experimental Botany
Volume66
Issue number19
DOIs
StatePublished - 1 Sep 2015

Bibliographical note

Publisher Copyright:
© 2015 The Author.

Keywords

  • Early vigour
  • Embryo
  • Embryo/endosperm ratio
  • Endosperm
  • Grain size
  • Tetraploid wheat
  • Triticum turgidum ssp. dicoccoides
  • Wheat domestication

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