DOI: 10.5061/dryad.x95x69pq3
title: High buffering potential of winter wheat composite cross populations to rapidly changing environmental conditions

description: 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 varieties under drought conditions of 2015. The results highlight the
 potential of CCPs to compete with line varieties while the overall
 similarity of the CCPs based on their origin and cycling history for
 agronomic traits indicate a high buffering potential under highly variable
 environmental conditions.
description: 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 <em>Stagonospora nodorum</em>
 and <em>Zymoseptoria tritici</em>, 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 m<sup>2</sup> per plot). The number of
 ears for ear-bearing tillers per m<sup>2</sup> and the
 percentage of counted ears with awns (awned ears) were recorded. From
 these samples, total biomass and kernel weight were also recorded to
 calculate the harvest index (HI) and kernel number per ear. Combine
 harvested grain yields (t/ha) and thousand kernel weights (TKWs) (g) were
 adjusted to 14% moisture content. The TKW (g) was measured three times per
 plot (the weight of 1000 kernels), and the mean of these three
 measurements was used for analysis. Stem length (measured from base of
 stem to start of ear) and ear length (awn length not included) were
 recorded for 45 randomly chosen mature plants per plot (<em>n
 </em>= 180 plants in total per entry).
 Protein content (%) was
 determined for all CCP entries and reference varieties in both generations
 and in both years. Protein content (%) was calculated according to seed
 nitrogen content (% N × 5.7), which was analysed using an Elementar
 Analysator vario MAX (Elementar Analysesysteme GmbH, Hanau, DE).