Schriften zu Genetischen Ressourcen - Genres

F. SEYIS, W. FRIEDT and W. LÜHS
Resynthesised Brassica napus as a genetic resource in rapeseed
improvement for quality and agronomic performance
F. SEYIS, W. FRIEDT and W. LÜHS 1
Abstract
The limited geographic range of oilseed rape (Brassica napus L. ssp. napus) and
intensive breeding has led to a comparatively narrow genetic basis in this crop species.
In contrast, B. rapa L. (syn. B. campestris L.) and B. oleracea L. are both highly
polymorphic and therefore offer a much broader genetic variability that can be exploited
for B. napus improvement via interspecific hybridisation (“resynthesis”) of the
original progenitors assisted by biotechnology. In general, the low yield performance
and conventional quality (high erucic acid-high glucosinolates rapeseed, HEAR) of
resynthesised B. napus is a handicap for the broad use of this novel genepool in
modern rapeseed breeding programmes. However, the discovery of lowerucic acid
mutants among B. oleracea accessions and the development of synthetic rapeseed
through wide crosses with respective 0- or 00-quality B. rapa genotypes will offer the
possibility to use this basic material as a genetic resource for quality and yield improvement
in oilseed rape.
Introduction
During the past 50 years, numerous efforts have focussed on exploring “novel”
germplasm and developing basic B. napus breeding stocks by using genetic resources
of B. rapa (turnip rape, turnip, Chinese cabbage, Indian sarson, toria, etc.)
and B. oleracea (kale, cabbage, Brussels sprouts, kohlrabi, cauliflower, sprouting
broccoli, wild kale, etc.) for wide hybridisation. The crop species B. napus, which encompasses
oilseed rape and some fodder crops (ssp. napus) as well as rutabaga or
swede turnips (ssp. napobrassica (L.) Hanelt), is a natural amphidiploid derived from
the diploid species B. rapa (2n=10, AA) and B. oleracea (2n=18, CC) (cf. DIEDERICH-
SEN 2001). Following the strategy of developing novel synthetic B. napus forms has
provided important basic germplasm for further improvements of seed yield, disease
and pest resistance as well as relevant seed quality traits (SONG et al. 1993, BECKER
et al. 1995, LÜHS and FRIEDT 1999, SEYIS et al. 2001, LÜHS et al. 2001).
1 Justus-Liebig-University Giessen
Institute of Crop Science and Plant Breeding I
Department of Plant Breeding
Heinrich-Buff-Ring 26-32
D-35392 Giessen, Germany
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