The glucosinolate (GSL) pattern of 93 resynthesized (resyn) rapeseed lines was examined over three years, and five stable genotypes with distinct GSL profiles were identified. Typically the resyn B. napus profile exhibited progoitrin as the main GSL, but contained sinigrin. The different GSL patterns of the four deviating lines are discussed with respect to the proposed biosynthetic pathway. Within the resyn and further extensive breeding materials, screening for Io'w lndolyl GSL contents resulted in finding one genotype with an extremely low 4-hydroxy-glucobrassicin and glucobrassicin content. Furthermore, other lines were identified, differing over a wide range of indolyl GSL contents. The values were stable over two years.
The performance of single cross hybrids between resynthesized (resyn) genotypes and varieties of rapeseed was tested in microplots. The results revealed strong genetic differences between the artificially synthesized rapeseed fortns for all the characters investigated, as well as for g.c.a. values. In particular, hybrids with resyn rapeseed exhibited a vigorous vegetative growth. It should, therefore, be beneficial to use resyn forms directly in fodder rape breeding programmes.Disturbances in fertility of the resyn material resulted in a low number of seeds per pod and consequent!)' in an inferior seed yield as compared to the varieties, although some high yielding combinations were also identified. Three-way hybrids with a 25 % genome share of the resyn rapeseed reached only lower vegetative performance as compared to the hybrids with a 50 % resyn genome but their performance in generative traits was generally superior. In respect to seed yield some progenies of three-way hybrids showed a higher plot performance than even the high yielding varieties. A further comparison between smgle-cross combinations of resyn X variety on the one hand and variety x variety on the other hand demonstrated th,at resyn genotypes, due to a distinct apical dominance, exhibited a pronounced expression of characters measured on the main stem. But in total, it is evident from the present findings that any hybridization with this resyn material does not promise immediate shortterm varietal improvement.
A broad spectrum of rapeseed (rape) lines as well as resynthesized (resyn) genotypes of B. napus were analyzed for their contents of sinapoyl esters. In the rape material the concentrations varied between 17.8 and 71.9 f^mol/g defatted seed meal and exhibited a heritability of h^ = 0.6. The resyn genotypes showed an even smaller variation but had a similar heritability. Therefore, no additional, immediately usable, genotypes with low sinapoyl ester concentrations could be created by a resynthesis.Key words: Brassica napus -resynthesized rapeseed -sinapine content -meal quality -genetic variability -heritability Phenolic compounds such as sinapoyl-esters are common microconstituents in most oilseeds. They affect the quality of the meals and oilcakes by interacting in a destructive manner with amino acids, by denaturing proteins and inhibiting enzymes (SOZULSKI 1979). In feeding experiments with laying hens, particular problems have been described. Sinapine normally is hydrolyzed to sinapic acid and choline, and the latter is further metabolized to trimethylamine by enteric bacteria. Thereafter, by the birds own enzyme, the trimethylamine is oxidized and excreted as trimethylamine oxide (BUTLER et al. 1982). Some races of hens, however, laying brown eggs, e.g. Rhode Island, exhibit a genetic defect: They are unable to oxidize trimethylamine and, therefore, their eggs have an unpleasant taint. This taint may be avoided by feeding rapeseed meal containing no sinapine. A technical removal of sinapine from rapeseed meal using different solvents proved to be insufficient and too expensive (DABROWSKI and SIEMIENIAK 1987). For such reasons, the genetic elimination by plant breeding seems to be the most promising strategy. According to THOMAS and VOM BRUCK (1985), the sinapine content in rapeseed meal varies from 0.8 % to 1.5 %. UPPSTROM and JOHANSSON (1985) found even smaller differences in winter and spring rapeseed of different geographic origins. Sinapine concentration in the meal of this material varied between 1.2 % and 2.0 %. Therefore, variation towards low levels seems to be rather limited in breeding materials. The present work, thus, aimed at the screening of unadapted germplasm and the estimation of heritability of the sinapoyl ester contents in the seed meal.Plant materials: 42 rapeseed (rape) lines were obtained by screening the broad B. napus germplasm of the Plant Breeding Institute, University Gottingen, in 1985 and 1986 for sinapoyl ester contents. In addition, 98 resynthesized (resyn) lines from interspecific crosses between Brassica oleracea and Brassica campestris (GLAND 1982) were included in the investigation. Due to low seed set, some lines were multiplied in 1987 as single plants in the greenhouse. Field performance was determined in Gottingen over three years, 1987-1989, with genotypes drilled in small observation plots (3.2 m^) in a complete block design, each with one replication. At flowering, four plants of each genotype were selfed by paper bags and the harvested seeds were analyzed for the...
Oil yield and agronomic properties are the most important targets for canola breeders ( Brassica napus L.) in northern Europe. In order to enhance Pioneer's canola oil yield breeding efforts, oil content was measured with near infrared (NIR) spectroscopy directly on a harvester (NIR spectroscopy on-combine) and, in addition, moisture, protein and glucosinolate content were determined. NIR spectroscopy, coupled with rapid harvesting, can significantly improve the quality and speed of oil yield determinations so they occur within a very narrow harvest time window. Moisture, oil, protein and glucosinolate calibrations were developed with 449 samples from the 2004 to 2005 harvests, comprising spectra from four diode array NIR spectrometers mounted on-combine. Applying these calibrations to an independent dataset from the 2006 harvest resulted in standard errors of prediction ( SEP) and coefficients of determination ( r2) of 0.41% and 0.93 for moisture, 0.7% and 0.84 for oil, 0.61% and 0.81 for protein, 4.0% and 0.22 for glucosinolates, respectively. Combining calibrations generated from the four instruments gave optimal predictions. Omitting data from any instrument decreased accuracy and precision, although dropping each instrument had a different effect on the measured values of the constituents. Each instrument produced very similar moisture and constituent predictions with a common sample set as indicated by high r2 and, thus, very similar ranking properties. Analysis of variance with the on-combine determinations led to lower residual variance for oil and similar variance for protein compared to those obtained with classical methods of sampling and laboratory NIR analyses. In summary, the results demonstrate that NIR spectroscopy on-combine is very promising to enhance breeding canola for higher oil yield.
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