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Using genetic mapping and genomics approaches in understanding and improving drought tolerance in pearl millet

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Relation http://oar.icrisat.org/37/
http://dx.doi.org/10.1093/jxb/erq265
 
Title Using genetic mapping and genomics approaches in
understanding and improving drought tolerance in pearl
millet
 
Creator Yadav, R S
Sehgal, D
Vadez, V
 
Subject Millets
 
Description Drought at the reproductive stage is a major constraint to pearl millet [Pennisetum glaucum (L.) R. Br.] productivity.
Quantitative trait locus (QTL) mapping provides a means to dissect complex traits, such as drought tolerance, into
their components, each of which is controlled by QTLs. Molecular marker-supported genotypic information at the
identified QTLs then enables quick and accurate accumulation of desirable alleles in plant breeding programmes.
Recent genetic mapping research in pearl millet has mapped several QTLs for grain yield and its components under
terminal drought stress conditions. Most importantly, a major QTL associated with grain yield and for the drought
tolerance of grain yield in drought stress environments has been identified on linkage group 2 (LG 2) which accounts
for up to 32% of the phenotypic variation of grain yield in mapping population testcrosses. The effect of this QTL has
been validated in two independent marker-assisted backcrossing programmes, where 30% improvement in grain
yield general combining ability (GCA) expected of this QTL under terminal drought stress conditions was recovered
in the QTL introgression lines. To transfer effectively favourable alleles of this QTL into pearl millet varieties that
otherwise are high yielding and adapted to specific agricultural zones, efforts are currently underway to develop
closely spaced gene-based markers within this drought tolerance (DT)-QTL. In this review, an overview is provided
of information on the genetic maps developed in pearl millet for mapping drought tolerance traits and their
applications in identifying and characterizing DT-QTLs. Marker-assisted transfer of desirable QTL alleles to elite
parent backgrounds, and results from introgression line validation in multiple terminal drought stress environments
are discussed. Current efforts undertaken towards delimiting the interval of a major DT-QTL mapping to LG 2, and
towards identifying candidate genes and physiologies underlying this QTL are presented. Highly specialized genetic
stocks [QTL-near-isogenic lines (NILs), a high-resolution cross, and a germplasm population] and genomic
resources (gene sequences, gene-based markers, and comparative genomics information) specifically developed
for these purposes are discussed.
 
Publisher Oxford University Press
 
Date 2011
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
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Identifier http://oar.icrisat.org/37/1/Yadav-Sehgal-Vadez_2011_-_JXB.pdf
Yadav, R S and Sehgal, D and Vadez, V (2011) Using genetic mapping and genomics approaches in understanding and improving drought tolerance in pearl millet. Journal of Experimental Botany, 62 (2). pp. 397-408.