In bread wheat (T. aestivum L.), grain yield improvement is highly associated with grain number per unit area. Current evidence suggests grain sink strength remains a critical yield-limiting factor. A novel hexaploid spring wheat (CMH79A.955) with a ?large-ear phenotype? was developed at CIMMYT, Mexico. The CMH79A.955 line expresses a longer rachis with 2-3 more spikelets than conventional CIMMYT spring wheats (Gaju et al., 2009). From the cross of CMH79A.955 and the UK winter wheat Rialto (a high radiation-use efficiency wheat) a doubled-haploid (DH) population was generated with 138 lines. The 138 DH lines were characterized in field experiments in the UK both at Thriplow and Sutton Bonington in 2006-7, 2007-8 and 2008-9, as ear rows and at commercial planting density (300 seeds/m2). Detailed phenotypic analysis of traits related to ear fertility and yield components was carried out in both locations. Using 411 DArT and 80 microsatellite markers a linkage map for the CMH79A.955 x Rialto DH population was developed 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 ear-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 BC2 stage. Initial results from the QTL analysis and advances in the backcross programme will be presented.

Global Wheat Program

English

INT1511

CIMMYT Staff Publications Collection