8th INTERNATIONAL WHEAT CONFERENCE

DM at anthesis), i.e. increased chaff DM cost per grain, with large spike phenotype. The
increased chaff DM was associated with an increased allocation of assimilate to the lemmas
and a higher rachis specific weight. From the analysis of the data set, physiological
avenues are proposed which may offer opportunities for breaking the negative linkage
between spike partitioning index and spike fertility index.
A linkage map was developed for the CMH79A.955 x Rialto DH population using 411
DArT and 80 microsatellite markers and Quantitative Trait Loci (QTL) analysis was carried
out. In collaboration with KWS UK Ltd, a backcross programme has been initiated
by crossing 35 DH lines showing high expression of spike-fertility traits to both Ashby
and Humber (spring and winter wheat types, respectively). After selection in the field
and with input from molecular marker analysis, the backcross programme has continued
with the development of 15 DH lines in the two UK recurrent parents, represented at
the BC 2 stage. Initial results from the QTL analysis and advances in the backcross programme
will be presented.
References
Gaju, O., Reynolds, M.P., Sparkes, D.L., Foulkes, M.J. 2009. Crop Science 49, 961-973.
Acknowledgements
We gratefully acknowledge the financial support of BBSRC, CIMMYT and University of
Nottingham.
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