Theoretical and Applied Genetics (2018) 131:973–984
Can spelt wheat be used as heterotic group for hybrid wheat
· Patrick Thorwarth
· Vilson Mirdita
· Elmar A. Weissman
· Guozheng Liu
· Tobias Würschum
C. Friedrich H. Longin
Received: 21 September 2017 / Accepted: 4 January 2018 / Published online: 16 January 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
Key message Spelt wheat is a distinct genetic group to elite bread wheat, but heterosis for yield and protein quality
is too low for spelt to be recommended as heterotic group for hybrid breeding in wheat.
Abstract The feasibility to switch from line to hybrid breeding is currently a hot topic in the wheat community. One limitation
seems to be the lack of divergent heterotic groups within wheat adapted to a certain region. Spelt wheat is a hexaploid wheat
that can easily be crossed with bread wheat and that forms a divergent genetic group when compared to elite bread wheat.
The aim of this study was to investigate the potential of Central European spelt as a heterotic group for Central European
bread wheat. We performed two large experimental ﬁeld studies comprising in total 43 spelt lines, 14 wheat lines, and 273
wheat–spelt hybrids, and determined yield, heading time, plant height, resistance against yellow rust, leaf rust, and powdery
mildew, as well as protein content and sedimentation volume. Heterosis of yield was found to be lower than that of hybrids
made between elite wheat lines. Moreover, heterosis of the quality trait sedimentation volume was negative. Consequently,
spelt wheat does not appear suited to be used as heterotic group in hybrid wheat breeding. Nevertheless, high combining
abilities of a few spelt lines with elite bread wheat lines make them interesting resources for pre-breeding in bread wheat.
Thereby, the low correlation between line per se performance and combining ability of these spelt lines shows the potential
to unravel the breeding value of genetic resources by crossing them to an elite tester.
A major objective of plant breeding is to develop high-yield-
ing varieties to increase crop productivity to feed a growing
human population. In allogamous maize, the shift to hybrid
breeding has facilitated strong increases in yield (Duvick
1999). In autogamous small grain cereals, such as wheat,
hybrid breeding has recently received renewed interest and
is considered as a potential strategy to increase yield and
to enhance yield stability (Longin 2016). However, a big
challenge is the identiﬁcation or development of heterotic
groups to ensure future progress of hybrid breeding and to
increase the relevance of general combining ability (GCA)
as compared to speciﬁc combing ability (SCA) (Dreisigacker
et al. 2005; Melchinger 1999). In the past, European wheat
breeders have exploited material across breeding programs
and countries. This substantial exchange of germplasm has
resulted in the genetic relatedness of European wheat culti-
vars even across countries and, thus, the absence of geneti-
cally distinct groups (Nielsen et al. 2014; Würschum et al.
2015; Boeven et al. 2016).
As one of the hexaploid wheats, spelt (T. aestivum ssp.
spelta) has the same genome constitution (AABBDD) as
bread wheat (T. aestivum ssp. aestivum). Between the
12th and the 19th century, spelt was one of the major
cereals in Southern Germany, Switzerland, and Austria.
Being replaced by the higher yielding and free-threshing
bread wheat, spelt was rediscovered beginning in the
1970s and is nowadays grown on ca. 100,000 ha, primar-
ily in the same three Central European countries (Longin
Communicated by Ian Mackay.
Electronic supplementary material The online version of this
article (http s://doi.org/10.1007 /s001 22-018-3052 -3) contains
supplementary material, which is available to authorized users.
* C. Friedrich H. Longin
State Plant Breeding Institute, University of Hohenheim,
70593 Stuttgart, Germany
Bayer Aktiengesellschaft, European Wheat Breeding Center,
06466 Gatersleben, Germany