Pw. Chee et al., Evaluation of a high grain protein QTL from Triticum turgidum L. var. dicoccoides in an adapted durum wheat background, CROP SCI, 41(2), 2001, pp. 295-301
Grain protein concentration (GPC) is an important component of durum wheat
(Triticum turgidum L, var. durum) quality. The 'Langdon'-Triticum turgidum
L. var. dicoccoides chromosome 6B substitution line [LDN(DIC-6B)] contains
the high GPC quantitative trait locus "QGpc.ndsu.6Bb," We evaluated the eff
ect of this quantitative trait locus on GPC, grain yield, and other agronom
ic traits in an adapted durum wheat background, verified its location on ch
romosome 6B and determined its relationship to the GPC locus previously ide
ntified. A recombinant inbred population consisting of 110 lines segregatin
g for high GPC was developed from the LDN(DIC-6B) with two doses of adapted
germplasm. This population was evaluated in the field for GPC at two locat
ions in 1995, and for GPC, grain yield, and other agronomic characteristics
at three locations in 1996, Segregation analysis for GPC shelved a bimodal
distribution, indicating a single genetic factor or a tightly linked gene
cluster controlling high GPC, This high GPC locus was insensitive to enviro
nmental conditions, Grain protein concentration was not correlated with pla
nt height, but was loosely correlated with grain yield and heading date. Qu
antitative trait locus analysis using simple regression and interval mappin
g procedures identified a locus flanked by Xcdo365 and Xmwg79 on chromosome
6B as having a major effect on GPC. This high GPC locus, which explained u
p to 72% of the phenotypic variance, accounted for a 15 g kg(-1) increase i
n average GPC, Selection for the two markers flanking the GPC QTL would be
highly effective in introgressing this QTL into durum wheat breeding progra
ms.