Mapping QTLs for grain hardness and puroindoline content in wheat (Triticum aestivum L.)

Abstract

Genes for puroindoline-a (Pin-a), puroindoline-b (Pin-b) and grain-softness proteins (GSP) have been shown to be linked to the dominant Ha locus responsible for the soft texture of the grain. Though linkage has been demonstrated of the puroindoline genes to the Ha locus, there is no clear evidence that puroindoline content is the product of the gene Ha. A segregating population of 115 recombinant inbred lines (RILs) originating from a cross between the hexaploid Synthetic wheat ( Triticum durum x Aegilops tauschii, W 7984) and the cultivar 'Opata' (M 85) was studied in two different experimental years to detect Quantitative Trait Loci (QTLs) for three traits: grain hardness (Hard), puroindoline-a (Pin-a) and puroindoline-b (Pin-b) contents. The detection of QTLs was performed using marker linear regression. Negative correlation coefficients (-0.86 and -0.80) were identified between grain hardness and puroindoline content (a and b, respectively) on data obtained in 1996. Results obtained in 1999 confirmed the negative correlation between Hard and Pin-a (-0.73); however a positive correlation coefficient was found with Pin-b content (0.41). Total phenotypic variation explained by each QTL was calculated (R2). For each of the Hard, Pin-a and Pin-b traits one major QTL was detected on the short arm of chromosome 5D, located close to the mta9 allele (puroindoline-a). For the first year (1996) the QTL in this region explained around 63% of the phenotypic variability in grain hardness, 77% in Pin-a and 45% in Pin-b contents. These values were confirmed in trials carried out in 1999 with a R2 value of 0.71, 0.72 and 0.25 for Hard, Pin-a and Pin-b, respectively. In 1996 and 1999 a second major QTL was detected for grain hardness on the long arm of the same chromosome. Present results indicate that it cannot be definitely concluded that puroindoline content represents a linear explanation for variations in grain hardness.

AB-QTL analysis in winter wheat: I. Synthetic hexaploid wheat (T. turgidum ssp. dicoccoides × T. tauschii) as a source of favourable alleles for milling and baking quality traits

“…The QTL for grain hardness on chromosome 5D, QGh.Z86-5D.a, in Z86 is at the same position as the Ha locus. In addition, Igrejas et al (2002) found that marker Xgwm190, which is located at our QTL, was only 5.8 cM distant to Xmta9 and Xmta10. The latter RFLP markers were very tightly linked, giving the same major QTL for grain hardness, puroindoline-a content and puroindoline-b content.…”

Fine Mapping and Marker Development for the Crossability Gene SKr on Chromosome 5BS of Hexaploid Wheat (Triticum aestivum L.)

“…The 5B homeologous GSP locus is linked closely to the crossability gene SKr: The rice homologous gene to GBR0233 near SKr, Os12g44150, is separated by only two genes in the rice genome annotation from a group of genes (Os12g44180-Os12g44250) that were identified previously as orthologous to the regions carrying the grain softness protein (GSP) gene on the short arm of wheat chromosomes group 5 (Sourdille et al 1996;Turner et al 1999;Igrejas et al 2002;Chantret et al 2004) (Figure 4) and the short arm of chromosome 5H in barley (Caldwell et al 2004). To assess whether SKr is in the vicinity of the GSP locus on 5B and derive new markers, SSR and insertion site-based polymorphism (ISBP) markers (Paux et al 2006) were designed from the sequence of the BAC clone 1793L02 (GenBank acc.…”

Effect of Genotype, Environment and Their Interaction on Quality Parameters of Wheat Breeding Lines of Diverse Grain Hardness

“…That is in agreement with the findings that locus Ha alone does not explain all the variation in grain hardness. Several studies have indicated that other regions of wheat genome are also responsible for grain hardness (Galande et al, 2001;Martin et al, 2001;Igrejas et al, 2002;Arbelbide and Bernardo, 2006;Narasimhamoorthy et al, 2006;Tsilo et al, 2011).…”