Diversität in der F5 von dynamisch evolvierenden Weizen Composite Cross Populationen

Summary

Three winter wheat composite cross (CC) populations were created in 2001 in the UK
consisting either of 20 modern wheat parents (called A Population), a subset of 12
high quality parents (Q), or a subset of 9 high yielding parents (Y). Seed of the F4 was
transferred to the University of Kassel in 2005 and the populations were grown since
then under organic and conventional conditions in well separated large (>100m2) plots
in two parallel sets (12 populations total) without conscious selection applied. In the
conventional system fungicides and insecticides were not applied to expose the
populations to natural pest and disease pressure. Morphological diversity, diseases,
and yield were assessed in the field every season. The parents and a total of 1379
single plants of 23 single seed progenies of the F5 were tested in the laboratory for
their combined resistance to three brown rust isolates. Only one progeny was
homogenous in reaction, all others were mixtures of two to eight three-locus
genotypes. Despite the supposed inbreeding structure of wheat one association in the
Q progenies was random suggesting recent out-crossing. Thus, diversity and
heterogeneity was still high in the F6 with evidence that out-crossing still played a role
and contributed to this heterogeneity.