P0335 The relationship of leaf angle and brassinosteroid response loci in durum wheat

Julio Isidro , AAFC-SPARC, Swift Current, SK, Canada
Ron Knox , AAFC-SPARC, Swift Current, SK, Canada
A.K. Singh , AAFC-SPARC, Swift Current, SK, Canada
F.R. Clarke , AAFC-SPARC, Swift Current, SK, Canada
R.M. DePauw , AAFC-SPARC, Swift Current, SK, Canada
Daryl J. Somers , Vineland Research and Innovation Centre, vineland Station, ON, Canada
Erect leaves enhance photosynthetic capacity and thus biomass production through greater sunlight capture. Leaf erectness is associated with brassinosteroid (BR) function in rice and barley, as well as in Arabidopsis, but no information on this relationship is available in wheat. The responsiveness of durum wheat to BR was identified on chromosome 4B, 7A, 3A and 3B. The aim of this work was to study the genetic variation of leaf angle in durum wheat (Triticum turgidum L. subsp. durum) to identify Quantitative Trait Loci (QTL) and to establish synteny with BR response loci in durum wheat. A doubled haploid population of 90 durum wheat lines developed from the cross ‘Strongfield’ x ‘Blackbird’ was studied in greenhouse and field experiments. Main stem leaf angle was measured at three developmental stages on the flag and penultimate leaves.  The analysis revealed putative leaf angle QTL on chromosomes 2A, 2B, 3A, 3B, 4B, 5B and 7A. There were also highly significant epistatic interactions between several loci for leaf angle. Chromosome 5B has synteny with chromosome 9 of rice and 3B with 3H of barley, where factors controlling leaf angle were previously reported to be located. Mapping leaf angle and BR response to the same region on chromosome 4B, 7A, 3A and 3B demonstrates a potential relationship between the two. Our results show the complexity of the leaf angle trait, and provide the basis for understanding the relationship among leaf angle, BR activity and biomass yield and to identify candidate genes in durum wheat.