title: Quantitative trait loci associated with traits determining grain and stover yield in pearl millet under terminal drought-stress conditions.
abstract: Drought stress during the reproductive stage is one of the most important environmental factors reducing the grain yield and yield stability of pearl millet. A QTL mapping approach has been used in this study to understand the genetic and physiological basis of drought tolerance in pearl millet and to provide a more-targeted approach to improving the drought tolerance and yield of this crop in water-limited environments. The aim was to identify specific genomic regions associated with the enhanced tolerance of pearl millet to drought stress during the flowering and grain-filling stages. Testcrosses of a set of mapping-population progenies, derived from a cross of two inbred pollinators that differed in their response to drought, were evaluated in a range of managed terminal drought-stress environments. A number of genomic regions were associated with drought tolerance in terms of both grain yield and its components. For example, a QTL associated with grain yield per se and for the drought tolerance of grain yield mapped on linkage group 2 and explained up to 23% of the phenotypic variation. Some of these QTLs were common across stress environments whereas others were specific to only a particular stress environment. All the QTLs that contributed to increased drought tolerance did so either through better than average maintenance (compared to non-stress environments) of harvest index, or harvest index and biomass productivity. It is concluded that there is considerable potential for marker-assisted backcross transfer of selected QTLs to the elite parent of the mapping population and for their general use in the improvement of pearl millet productivity in water-limited environments.
authors.affiliation: Institute of Grassland and Environmental Research (IGER), Plas Gogerddan, Aberystwyth, Ceredigion SY233 EB, Wales, United Kingdom. rattan.yadav@bbsrc.ac.uk
authors.forename: R S
authors.initials: RS
authors.lastname: Yadav
authors.forename: C T
authors.initials: CT
authors.lastname: Hash
authors.forename: F R
authors.initials: FR
authors.lastname: Bidinger
authors.forename: G P
authors.initials: GP
authors.lastname: Cavan
authors.forename: C J
authors.initials: CJ
authors.lastname: Howarth