A QTL on chromosome 6A in bread wheat.pdf

ORIGINAL PAPER A QTL on chromosome 6A in bread wheat (Triticum aestivum) is associated with longer coleoptiles, greater seedling vigour and final plant height W. Spielmeyer ? J. Hyles ? P. Joaquim ? F. Azanza ? D. Bonnett ? M. E. Ellis ? C. Moore ? R. A. Richards Received: 20 October 2006 / Accepted: 17 March 2007 / Published online: 11 April 2007
Springer-Verlag 2007 Abstract Wheat crops with greater early vigour shade the soil surface more rapidly and reduce water loss. Evaporative losses affect water-use efficiency particularly in drier regions where most of the rainfall occurs early in the growing season before canopy closure. Greater seedling leaf area and longer coleoptiles are major determinants of increased vigour and better crop estab- lishment. A previously developed high vigour breeding line ‘Vigour 18’ was used to establish a large re- combinant inbred family and framework map to identify a QTL on chromosome 6A that accounted for up to 8% of the variation for coleoptile length, 14% of seedling leaf width and was associated with increased plant height. The SSR marker NW3106, nearest to the 6A QTL, was also associated with greater leaf width in a breeding population that was also derived from a cross involving the high vigour donor line ‘Vigour18’. The association between the NW3106 marker and coleoptile length was validated in a second breeding population which was developed using an unrelated long coleoptile donor line. The ‘Vigour18’ allele of the QTL on chro- mosome 6A promoted coleoptile length and leaf width during early plant growth but was also associated with increased plant height at maturity. Markers linked to the QTL are being used to increase the frequency of in- creased vigour and long coleoptile alleles in early gen- erations of breeding populations. Keywords Wheat
Vigour
Coleoptile
QTL analysis Introduction Good crop establishment requires shoots to emerge from the soil and develop leaf area rapidly. Wheat cultivars with more vigoro