Using the UK reference population Avalon×Cadenza as a platform to comparebreeding strategies in elite Western European bread wheat

Wheat breeders select for qualitative and quantitative traits, the latter often detected asquantitative trait loci (QTL). It is, however, a long procedure from QTL discovery to thesuccessful introduction of favourable alleles into new elite varieties and finally intofarmers’ crops. As a proof of principle for this process, QTL for grain yield (GY), yieldcomponents, plant height (PH), ear emergence (EM), solid stem (SS) and yellow rustresistance (Yr) were identified in the segregating UK bread wheat referencepopulation, Avalon×Cadenza. Among the 163 detected QTL were several not reportedbefore: 17 for GY, the major GY QTL on 2D; a major SS QTL on 3B; and Yr6 on 7B.Common QTL were identified on ten chromosomes, most interestingly, grain number(GN) was found to be associated with Rht-D1b; and GY and GN with a potential newallele of Rht8. The interaction of other QTL with GY and yield components wasdiscussed in the context of designing a UK breeding target genotype. Desirablecharacteristics would be: similar PH and EM to Avalon; Rht-D1b and Vrn-A1b alleles;high TGW and GN; long and wide grains; a large root system, resistance to diseases;and maximum GY. The potential of the identified QTL maximising transgressivesegregation to produce a high yielding and resilient genotype was demonstrated bysimulation. Moreover, simulating breeding strategies with F2 enrichment revealed thatthe F2-DH procedure was superior to the RIL and the modified SSD procedure toachieve that genotype. The proposed strategies of parent selection and breedingmethodology can be used as guidance for marker-assisted wheat breeding.