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markers for marker-assisted selection (MAS) and map
based cloning. Several such studies for other traits in
wheat and for a number of traits in other crops have
been conducted in the past. Theses studies together
with the present study suggest that whenever,
hundreds of QTLs based on a large number of studies
that involved a number of mapping populations are
available in the published literature, meta-QTL
analysis can be a useful reductionist approach to bring
down the number of genuine and real QTLs to a
reasonable number for further study and possible use.
The approach also allows narrowing down the
confidence interval for each QTL inferred from
meta-QTL analysis and overcomes a part of the
difficulty and confusion that exist due to redundancy
in the number of QTLs in overlapping genomic
regions. In particular for PHST and dormancy in
wheat, the present study allowed identification of 8
meta-QTLs on four chromosomes (3A, 3B, 3D and
4A), which can be immediately used. Since candidate
genes have also been identified, one would need to
verify whether or not the candidate genes
taVp1
(vivipary gene) and
TaGA20
-
ox1
(gibberellin20
-
oxidase gene) are really responsible for PHST and
dormancy in wheat. Further studies, however, need to
be conducted to fully understand the genetic
architecture of PHST and dormancy, since the present
study could not utilize any QTLs reported on other 17
chromosomes of wheat. Also, no information on
epistatic QTLs or on eQTLs and epigenetic modify-
cations was available for the present study, although
we know that these may also play an important role in
determining the level of PHST in a wheat genotype.
Authors' Contributions
ST participated in the design of the study, performed analysis
and drafted the manuscript. PKG participated in the design and
supervision of the study and preparation of the final manuscript.
Both the authors have read and approved the final manuscript.
Acknowledgements
Thanks are due to Professor HS Balyan (Department of
Genetics and Plant Breeding, CCS University, Meerut, India)
for reading the manuscript and giving useful comments, to
Professor B. Ramesh (Head of the Department of Genetics and
Plant Breeding, CCS University, Meerut, India), for providing
facilities, to Dr. Fabian Chardon (INRA Centre, Versailles,
France) for his help in constructing overview curve and to Dr.
Akshay Pradhan (Department of Genetics, University of Delhi
South Campus, India) and Dr. Satish Kumar Yadav (Centre for
Genetic Manipulation of Crop Plants, University of Delhi
South Campus, India) for their help in meta-analysis.
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