title: Genetic dissection of grain yield in bread wheat. I. QTL analysis.
abstract: Grain yield forms one of the key economic drivers behind a successful wheat (Triticum aestivum L.) cropping enterprise and is consequently a major target for wheat breeding programmes. However, due to its complex nature, little is known regarding the genetic control of grain yield. A doubled-haploid population, comprising 182 individuals, produced from a cross between two cultivars 'Trident' and 'Molineux', was used to construct a linkage map based largely on microsatellite molecular makers. 'Trident' represents a lineage of wheat varieties from southern Australia that has achieved consistently high relative grain yield across a range of environments. In comparison, 'Molineux' would be rated as a variety with low to moderate grain yield. The doubled-haploid population was grown from 2002 to 2005 in replicated field experiments at a range of environments across the southern Australian wheat belt. In total, grain yield data were recorded for the population at 18 site-year combinations. Grain yield components were also measured at three of these environments. Many loci previously found to be involved in the control of plant height, rust resistance and ear-emergence were found to influence grain yield and grain yield components in this population. An additional nine QTL, apparently unrelated to these traits, were also associated with grain yield. A QTL associated with grain yield on chromosome 1B, with no significant relationship with plant height, ear-emergence or rust resistance, was detected (LOD > or =2) at eight of the 18 environments. The mean yield, across 18 environments, of individuals carrying the 'Molineux' allele at the 1B locus was 4.8% higher than the mean grain yield of those lines carrying the 'Trident' allele at this locus. Another QTL identified on chromosome 4D was also associated with overall gain yield at six of the 18 environments. Of the nine grain yield QTL not shown to be associated with plant height, phenology or rust resistance, two were located near QTL associated with grain yield components. A third QTL, associated with grain yield components at each of the environments used for testing, was located on chromosome 7D. However, this QTL was not associated with grain yield at any of the environments. The implications of these findings on marker-assisted selection for grain yield are discussed.
authors: Australian Grain Technologies Pty Ltd, University of Adelaide, Roseworthy Campus, Roseworthy, SA 5371, Australia. haydn.kuchel@ausgraintech.com
authors: H
authors: H
authors: Kuchel
authors: K J
authors: KJ
authors: Williams
authors: P
authors: P
authors: Langridge
authors: H A
authors: HA
authors: Eagles
authors: S P
authors: SP
authors: Jefferies
mesh_terms: D002874:Chromosome Mapping; D003433:Crosses, Genetic; D005819:Genetic Markers; D006824:Hybridization, Genetic; D040641:Quantitative Trait Loci; D012639:Seeds / Q000235:genetics*; D014908:Triticum / Q000033:anatomy & histology / Q000235:genetics*
chemical_list: D005819:Genetic Markers
references: Theor Appl Genet. 2006 Feb;112(4):688-98
references: 16369760
references: Theor Appl Genet. 2004 Sep;109(5):933-43
references: 15243706
references: Theor Appl Genet. 2002 Nov;105(6-7):921-936
references: 12582918
references: Genetics. 1994 Apr;136(4):1447-55
references: 8013917
references: Genome. 2005 Oct;48(5):870-83
references: 16391693
references: Theor Appl Genet. 2005 Mar;110(5):865-80
references: 15719212
references: Genome. 1993 Jun;36(3):476-82
references: 18470001
references: Theor Appl Genet. 2006 Oct;113(6):1103-12
references: 16896709
references: Theor Appl Genet. 2002 Nov;105(6-7):1038-1042
references: 12582931
references: Mamm Genome. 1999 Apr;10(4):327-34
references: 10087288
references: Theor Appl Genet. 2006 May;112(8):1480-6
references: 16538511
references: Theor Appl Genet. 1983 Sep;66(3-4):249-56
references: 24263924
references: Theor Appl Genet. 2003 Apr;106(6):1032-40
references: 12671751