Schriften zu Genetischen Ressourcen - Genres

F. SEYIS, W. FRIEDT and W. LÜHS
Novel synthetic rapeseed with low erucic acid content
Individual zero-erucic B. oleracea plants belonging to the three accessions ‘Kashirka
202’, ‘Ladozhskaya’ and ‘Eisenkopf’ (LÜHS et al. 2000) were crossed with different B.
rapa quality types, viz. ‘Asko’ (0, spring fodder rape), an apetalous B. rapa line and
‘Reward’ (both 00, yellow-seeded spring type), and two 00-winter type lines (‘Q3F’
and ‘SWSP’). The efficiency of interspecific crosses was aided by embryo rescue.
Cuttings from these hybrids were treated with colchicine in order to obtain amphidiploid
B. napus plants (cf. LÜHS and FRIEDT 1999, SEYIS et al. 2001).
Results and discussion
Resynthesised rapeseed as a resource in hybrid breeding
The experimental hybrids (TH1-TH24) were checked for hybridity; as expected all of
them showed an intermediate seed oil quality with erucic acid contents ranging from
8.3 to 40.4%. The results of the yield trial are presented in Fig. 1. Regarding relative
seed yield (‘Senator‘=100, 30.0 dt/ha), the left streaky columns represent the hybrids
derived from the female line ‘MSL 506c’, while the right grey columns represent the
hybrids belonging to ‘MSL 510c’. The average seed yield of the 25 genotypes was
33.6 dt/ha. Hybrids developed from the female parent ‘MSL-506c’ tended to give
higher seed yields compared to hybrids from ‘MSL-510c’. The three synthetic lines
‘RS 578d’ (‘BK 2256’ × ‘Y.S.’), ‘RS SF 306’ (‘Y.S.’ × ‘BK 3094’) and ‘RS 239b’ (‘BK
2287’ × ‘Y.S.’), whose experimental hybrids showed the best results (Fig. 1), are
considered as promising material.
Novel synthetic rapeseed with low erucic acid content
With regard to oilseed rape, current double-low (canola) breeding material seems to
be closely related and intensive quality breeding has also contributed to narrow the
genetic base of this crop species (VOSS et al. 1998). On the other hand, the availability
of effective hybridisation control systems has enabled the development of hybrid
cultivars and has led to a demand for maximum diversity among breeding material.
Due to its poor agronomic performance and seed quality, the establishment of a new
genepool based on artificial B. napus is limited. One strategy to exploit this novel
germplasm in rapeseed improvement with minimum losses neither of seed quality
nor genetic divergence is seen in new resynthesis experiments using zero-erucic B.
oleracea mutants, which we have identified previously (LÜHS et al. 2000). In a preliminary
experiment we developed 16 amphihaploid hybrids from the reciprocal
crosses B. rapa ‘Asko’ × zero-erucic acid B. oleracea forms. Seed oil analysis of the
first individual hybrid (‘Kashirka 202’ × ‘Asko’) revealed a zero-erucic acid phenotype
as expected (SEYIS et al. 2001). The results of the B. napus resynthesis experiments
using B. rapa cultivars other than ‘Asko’ as female parent are summarised in Tab. 1.
Most of amphihaploid individuals in vitro were obtained in these cases where the
apetalous line was used as B. rapa parent (Tab. 1).
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