High buffering potential of winter wheat composite cross populations to rapidly changing environmental conditions

A winter wheat composite cross population (CCP), created in the UK in 2001, has been grown in Germany, Hungary and the UK since 2005 (F5 generation). In 2008/9 (F8), a cycling pattern for the populations was developed between partners to test the effects of rapidly changing environments on agronomic performance. One CCP was grown by eight partners for one year and subsequently sent to the next partner, creating “cycling CCPs” with different histories. In 2013, all eight cycling CCPs and the three non-cycling CCPs (from Germany, Hungary and UK) were included in a two-year experiment in Germany with three line varieties to compare agronomic performance and morphological characteristics. Differing seed weight of the F13 at sowing affected some agronomic parameters under drought conditions in 2014/15, but not under less stressful conditions in 2013/14. In both experimental years, the CCPs were comparable to the line varieties in terms of agronomic performance, with some CCPs outyielding the..., Foliar diseases caused by fungal pathogens were assessed on 10 plants per plot at BBCH stages 45–55 (26 May 2014 and 29 May 2015) and BBCH stages 60–70 (16 June 2014 and 17 June 2015). Non-green leaf area (NGLA) was recorded as a percentage of the flag leaf (F), the leaf below the flag leaf (F-1), and, if possible, the F-2 leaf (first assessment only). The two main foliar leaf diseases observed were also recorded at each assessment date. Due to the strong similarity of symptoms between Stagonospora nodorum and Zymoseptoria tritici, these two pathogens were not distinguished separately from one another in the assessments. The occurrence of foot diseases was low in 2013/14 and close to zero in 2014/15, and as such, they were not considered relevant to the agronomic results.
Morphological assessments were performed on three 0.5-m rows of mature plants cut as close to the ground as possible from each plot (0.450 m2 per plot). The number of ears for ear-bearing tillers per m2 and the percent...,