Molecular mapping of stomatal‐conductance‐related traits in durum wheat (Triticum turgidum ssp. durum)

Abstract

The most promising traits identified in wheat to raise yield potential via an increase in biomass accumulation are stomatal conductance and stomatalconductance-related traits, such as carbon isotope discrimination (CID) and photosynthetic rate. The evaluation of the extent of genetic variation and the mapping of chromosomal regions controlling these traits are essential for the development of effective breeding strategies in durum wheat. A population of 161 F2-derived, F8-F9 recombinant inbred lines obtained from a cross between durum wheat (Triticum turgidum ssp. durum) cultivars Ofanto and Cappelli was phenotyped for heading date, plant height, leaf porosity, CID and chlorophyll concentration (estimated through the SPAD index) for 2007/2008 and 2008/2009 seasons, at Ottava, Sardinia (Italy) under irrigated conditions. The genotype mean heritability for leaf porosity, CID and chlorophyll concentration was moderate in size. Six quantitative trait loci were detected for leaf porosity, four for chlorophyll concentration, but only one for CID, because of the small variation expressed in the population for this trait under these experimental conditions. The quantitative trait loci for leaf porosity located on chromosome 3B appear to be more stable with respect to the others, and different microsatellite markers are positioned within the interval of the quantitative trait loci, or in their vicinity, that represent useful tools in programmes for selection assisted by molecular markers.

Mapping of QTLs Associated with Yield and Yield Related Traits in Durum Wheat (Triticum durum Desf.) Under Irrigated and Drought Conditions

“…Two Hd QTLs on chromosome 5A have been reported by [32]. Moreover, [37] discovered an Hd QTL on chromosome 5A, affirming the finding of this study. On chromosome 7B, [29] have located an Hd QTL between 0 and 44.3 cM whereas our QTL (Q.RHd_S1.NIAB-7B) is located at 42.5 cM confirming the findings of [29].…”

“…[35] also located a Tr QTL in the distal region of chromosome 5AL. The QTL QTrD_S1.NIAB.7B.2 is connected to marker Xbarc276, which is the same marker reported by [37] to be linked with Tr under irrigated conditions on chromosome 7B.…”

“…[38] located a QTL linked to Tr under irrigated conditions at the distal end of chromosome 5AS, whereas the QTL QTr_S2.NIAB-5A in our investigation was at the far end of chromosome 5AL, indicating that QTr_S2.NIAB-5A is a novel QTL. Similarly, the two QTLs (QTr_S2.NIAB.5B and QRTr_S2.NIAB.5B) at 158 cM linked to marker Xgwm408 are highly comparable to one identified by [37] where the authors located a QTL linked to transpiration rate at early grain filling stage under irrigated conditions. Ref.…”

“…Moreover, it is also the site of many other QTLs linked to spike related traits in this study indicating that plant development influences spike related traits and in turn final yield. It should be mentioned that a flowering time locus has been reported by [37] on chromosome 3AL. Another QTL QHd_S1.NIAB-5A is linked to Yd, MP and ST QTLs in this study.…”

“…Ref. [37] detected several QTLs linked to leaf porosity (LP) on the distal end of chromosome 3BS. Our QTL QScD_S2.NIAB-3B at 13.91 cM on 3B might correspond to any of the LP QTLs of [37].…”