High Erucic Acid Research Articles

Status and perspectives of breeding for enhanced yield and quality of oilseed crops for Europe

Vegetable oils are a high-value agricultural commodity for use in refined edible oil products and as renewable industrial or fuel oils, and as the world population increases demand for high-quality seed oils continues to grow. Worldwide the oilseed market is dominated by soybean (Glycinemax), followed by oilseed rape/canola (Brassicanapus). In Europe the major oilseed crop is oilseed rape (B. napus), followed some way behind by sunflower (Helianthusannuus) and other minor crops like linseed (Linumusitatissimum) or camelina (Camelinasativa). The seed oil of these crops is characterized by a specific quality, i.e. fatty acid composition and other fat-soluble compounds: Camelina and linseed oils are characterised by high contents of linolenic acid (C18:3); in sunflower very high-oleic (up to 90% C18:1) types exist in addition to classical high-linoleic (C18:2) oilseeds; in B. napus a broad diversity of oil-types is available in addition to the modern 00 (canola) type, e.g. high-erucic acid rapeseed or high-oleic and low-linolenic cultivars. Moreover, vegetable oils contain valuable minor compounds such as tocopherols (vitamin E). Increases of such contents by breeding have lead to value-added edible oils. After oil extraction, oilseed meals—such as rapeseed extraction meal—contain a high-quality protein that can be used as a valuable animal feed. However, in comparison to soybean the meal from oilseed rape also contains relatively high amounts of anti-nutritive fibre compounds, phenolic acids, phytate and glucosinolates. Breeding efforts with respect to meal quality are therefore aimed at reduction of anti-nutritive components, while increasing the oil content, quality and yield also remains a major aim in oilseed rape breeding. This review article provides a general overview of the status of oilseed production in Europe and uses examples from winter oilseed rape to illustrate key breeding aims for sustainable and high-yielding production of high-quality vegetable oil. Emphasis is placed on analytical tools for high-throughput selection of overall seed quality.

Assessment of agronomic performance and heterosis for agronomic traits in hybrid high erucic acid rapeseed (HEAR)

Twelve genetically diverse and geographically distinct high erucic acid rapeseed (HEAR) Brassica napus L. cultivars/lines were selected and crossed by hand emasculation in a topcross design to produce 45 F1 hybrid combinations. Seven of the twelve parents were HEAR cultivars/lines developed by the University of Manitoba (UM) and the remaining five parents were proprietary European (EU) HEAR cultivars/lines. Adequate seed was produced to evaluate the hybrids and parents in replicated yield trials in six environments in Manitoba during 2004 and 2005. Vigor, days to first flower, days to maturity, lodging, plant height, and seed yield were assessed. The hybrids were generally more vigorous, taller and more lodging resistant than their parents with similar days to first flower and days to maturity as their earlier parents. The best hybrids in this study displayed high parent heterosis for seed yield of up to 143% and commercial heterosis for seed yield of up to 99%. These hybrids were from the most genetically diverse UM × EU crosses. HEAR hybrids appear very promising approach to increase seed yields in this crop. Key words: Brassica napus L., HEAR, heterosis, hybrids, genetic diversity

Breeding for improved oil and meal quality in rape (Brassica napus L.) and turnip rape (Brassica campestris L.)

The plant breeding in rapeseed is to-day strongly directed towards improved oil and meal quality. For edible purposes an oil free from erucic and eicosenoic acid, with high linoleic and low linolenic acid content is desirable, while for technical purposes a high erucic acid content is demanded. The combination of the half-seed and the backcross methods has implied considerable advantages in the breeding work in comparison with the inbreeding method. As a result Gulliver, a high-yielding, low-erucic-acid variety of summer rape, was released in 1977. Removal of the glucosinolates from the rape meal will considerably increase its feed-stuff value. Besides, a turnover to yellow-seeded material is advantageous to the exploitation of the low glucosinolate meal as a protein source for human beings. The breeding work has resulted in promising lines of rape and turnip rape low in both erucic acid and glucosinolate content. In summer turnip rape material including also high linoleic acid content and yellow seed colour is built up.

Increasing erucic acid content through combination of endogenous low polyunsaturated fatty acids alleles with Ld-LPAAT + Bn-fae1 transgenes in rapeseed (Brassica napus L.)

High erucic acid rapeseed (HEAR) oil is of interest for industrial purposes because erucic acid (22:1) and its derivatives are important renewable raw materials for the oleochemical industry. Currently available cultivars contain only about 50% erucic acid in the seed oil. A substantial increase in erucic acid content would significantly reduce processing costs and could increase market prospects of HEAR oil. It has been proposed that erucic acid content in rapeseed is limited because of insufficient fatty acid elongation, lack of insertion of erucic acid into the central sn-2 position of the triaclyglycerol backbone and due to competitive desaturation of the precursor oleic acid (18:1) to linoleic acid (18:2). The objective of the present study was to increase erucic content of HEAR winter rapeseed through over expression of the rapeseed fatty acid elongase gene (fae1) in combination with expression of the lysophosphatidic acid acyltransferase gene from Limnanthes douglasii (Ld-LPAAT), which enables insertion of erucic acid into the sn-2 glycerol position. Furthermore, mutant alleles for low contents of polyunsaturated fatty acids (18:2 + 18:3) were combined with the transgenic material. Selected transgenic lines showed up to 63% erucic acid in the seed oil in comparison to a mean of 54% erucic acid of segregating non-transgenic HEAR plants. Amongst 220 F(2) plants derived from the cross between a transgenic HEAR line and a non-transgenic HEAR line with a low content of polyunsaturated fatty acids, recombinant F(2) plants were identified with an erucic acid content of up to 72% and a polyunsaturated fatty acid content as low as 6%. Regression analysis revealed that a reduction of 10% in polyunsaturated fatty acids content led to a 6.5% increase in erucic acid content. Results from selected F(2) plants were confirmed in the next generation by analysing F(4) seeds harvested from five F(3) plants per selected F(2) plant. F(3) lines contained up to 72% erucic acid and as little as 4% polyunsaturated fatty acids content in the seed oil. The 72% erucic acid content of rapeseed oil achieved in the present study represents a major breakthrough in breeding high erucic acid rapeseed.

Inheritance and variation of erucic acid content in a transgenic rapeseed (Brassica napus L.) doubled haploid population

Erucic acid (22:1) is a valuable renewable resource for the oleochemical industry. Currently available high erucic acid rapeseed cultivars contain only about 50% erucic acid in the seed oil. A substantial increase of the erucic acid content of the rapeseed oil could increase market prospects. The transgenic line TNKAT, over expressing the rapeseed fatty acid elongase gene (fae1) and expressing the Ld-LPAAT gene from Limnanthes douglasii was crossed with the line 6575-1 HELP (high erucic and low polyunsaturated fatty acid). A from the F1 plants produced population of 90 doubled haploid (DH) lines was tested in a greenhouse with three replicates. Parental lines TNKAT and 6575-1 HELP contained 46 and 50% erucic acid in the seed oil, respectively. In the DH population the erucic acid content ranged between 35 and 59%. The Ld-LPAAT + Bn-fae1.1 transgene showed a 1:1 segregation. The transgenic DH lines contained up to 8% trierucolyglycerol, but surprisingly had a by 2.3% lower erucic acid content compared to the non-transgenic segregants. Results indicated that the ectopically expressed fae1.1 gene may not be functional. The DH population also showed a large quantitative variation for PUFA content ranging from 6 to 28% (TNKAT: 21%, 6575-1 HELP: 8%). Regression analysis showed that in the DH population a 10% reduction in PUFA content led to a 4.2% increase in erucic acid content. Development of locus specific PCR primers for the two resident erucic acid genes fae1.1 (A-genome) and fae1.2 genes (C-genome) of rapeseed allowed sequencing of the respective alleles from TNKAT and 6575-1 HELP. Single nucleotide polymorphisms were only found for the fae1.1 gene. Use of allele specific fae1.1 PCR primers, however, did not reveal a significant effect of the fae1.1 allele from either parent on erucic acid content. The high erucic acid low polyunsaturated fatty acid DH lines and the fae1 locus specific primers developed in the present study should be useful in future studies aimed at increasing erucic acid content in rapeseed.

Development and validation of gas chromatography and real‐time quantitative PCR for the quantification of landscape‐scale gene flow from varieties of high erucic acid (HEAR) oilseed rape

AbstractBACKGROUND: High erucic acid oilseed rape (HEAR) was tested as a source crop for estimates of regional geneflow. Two methods to detect HEAR in low erucic acid oilseed rape (LEAR) were compared: real‐time quantitative PCR (qPCR) and gas chromatography (GC).RESULTS: Fields (2.5 ha) of a LEAR variety (0.028% EA) in Tayside and Hertfordshire were juxtaposed adjacent to and 1 km distant from a HEAR (44% EA) field. The LEAR variety was a varietal association to ensure high cross‐pollination (CP). The methods were highly correlated, measuring between 30% and 0.5% CP. However, the qPCR method became unreliable below 0.5% CP, whereas GC was robust enough to detect raised EA equivalent to one F1 seed in 500 (0.2%). A statistical mixture model was fitted to the distributions of EA in samples in order to assign a CP value to each 500‐seed sample. Declines of CP from 30% to < 1%, and EA from 5% to 0.2%, with distance up to 150 m in the near fields was best fitted with a power function. The combined mean EA for both far fields was 0.11%, well above the background LEAR value of 0.028%, and mean CP was 0.36%.CONCLUSIONS: The GC method of detection raised %EA should be a reliable and high‐throughput means of estimating %CP between fields, provided the %EA of single F1 seed in receptor fields is measured to confirm the presence of F1 seed. Copyright © 2008 Society of Chemical Industry

Interspecific cross of Brassica oleracea var. alboglabra and B. napus: effects of growth condition and silique age on the efficiency of hybrid production, and inheritance of erucic acid in the self-pollinated backcross generation

Interspecific hybrids were produced from reciprocal crosses between Brassica napus (2n = 38, AACC) and B. oleracea var. alboglabra (2n = 18, CC) to introgress the zero-erucic acid alleles from B. napus into B. oleracea. The ovule culture embryo rescue technique was applied for production of F1 plants. The effects of silique age, as measured by days after pollination (DAP), and growth condition (temperature) on the efficiency of this technique was investigated. The greatest numbers of hybrids per pollination were produced under 20°/15°C (day/night) at 16 DAP for B. oleracea (♀) × B. napus crosses, while under 15°/10°C at 14 DAP for B. napus (♀) × B. oleracea crosses. Application of the ovule culture technique also increased the efficiency of BC1 (F1 × B. oleracea) hybrid production by 10-fold over in vivo seed set. The segregation of erucic acid alleles in the self-pollinated backcross generation, i.e. in BC1S1 seeds, revealed that the gametes of the F1 and BC1 plants carrying a greater number of A-genome chromosomes were more viable. This resulted in a significantly greater number of intermediate and a smaller number of high-erucic acid BC1S1 seeds.

Inheritance of long chain fatty acid content in rapeseed (Brassica napus L.)

A large industrial oil market has recently developed for high erucic acid (>500 g kg−1) rape (Brassica napus L.) cultivars. This research was conducted to: (i) determine genetic effects for five fatty acids, (ii) determine if maternal effects influence fatty acid content of progeny, and (iii) estimate correlations among fatty acid contents in hybrid progeny. Lines with very high erucic acid content and very low erucic acid content were used to develop eight generations to estimate additive, dominance, and epistatic effects for fatty acid content using Generation Means Analyses. Mean oleic, linoleic, linolenic, eicosenoic and erucic acid content differed among generations and additive genetic effects were important for control of all five fatty acids, contributing from 84% to 97% of the total sums of squares for each fatty acid. Epistasis was observed in the inheritance of eicosenoic acid. Maternal effects were not detected.

Relationship of seed quality traits for greenhouse-grown versus field-grown high erucic acid rapesseed: Is seed quality trait selection for greenhouse-grown seed worthwhile?

A study of the relationship of seed quality traits for greenhouse-grown and field-grown seed samples was conducted. Early generation high erucic acid rapeseed (HEAR) cross progeny were grown in the greenhouse, selfed and then the selfed seeds were grown in the field at the University of Manitoba. The oil, protein, erucic acid and glucosinolate concentrations of greenhouse-grown versus field-grown seed samples were compared. There were differences (P ≤ 0.01) between the means of all seed quality traits for greenhouse-grown versus field-grown seed samples. The mean oil, protein and erucic acid concentrations of field-grown seed samples were higher than for greenhouse-grown seed samples. In contrast, the mean glucosinolate concentration of greenhouse-grown seed samples was higher than for field-grown seed samples. Rank correlations between greenhouse-grown seed samples and field-grown seed samples for all seed quality traits were significant but moderate in magnitude. Selection for oil, protein, erucic acid and glucosinolate concentration in greenhouse-grown seed samples dramatically increased the number of high seed quality F4 families in the field and was successful for all seed quality traits. It is concluded that seed quality selection in greenhouse-grown seed samples is worthwhile and that this procedure could lead to greater efficiencies in Brassica plant breeding programs. Key words: Rapeseed (Brassica napus L.), oil, protein, erucic acid, glucosinolates

Novel seed oil types of Ethiopian mustard with high levels of polyunsaturated fatty acids

Oils rich in polyunsaturated fatty acids linoleic acid and linolenic acid have important industrial applications, both as drying oils in the manufacture of paints and coatings as well as in formulation of pharmaceuticals and nutraceuticals. However, no oil types with high levels of polyunsaturation have been developed so far in Brassica oilseed crops. The objective of the present research was to select for high levels of linoleic acid and linolenic acid in Ethiopian mustard ( Brassica carinata A. Braun). Selection started from the F 3 (S 0) seed generation of crosses involving the high oleic acid, high erucic acid line N2-3591, the low linolenic, high erucic acid line HF-186, and the zero erucic acid line 25X-1. The analysis of individual S 0 seeds showed ranges of variation with maximum levels of 68.9% linoleic acid and 36.4% linolenic acid. Selection for increased levels of linoleic acid resulted in a S 1:2 high linoleic acid line BC-HL that showed average linoleic acid contents of 62.5%, 58.3%, and 59.6%, respectively in three contrasting environments, compared to 47.8%, 45.8%, and 52.1%, respectively in a high linoleic acid check line. Selection for increased levels of linolenic acid resulted in a S 1:2 high linolenic acid line BC-HLN that showed average linolenic acid contents of 27.1%, 25.8%, and 26.3%, respectively in the mentioned environments, compared to 23.9%, 21.2%, and 19.4%, respectively in a high linolenic acid check line. Both lines developed in the present research possess novel fatty acid profiles not available so far in Brassica oilseed crops and they may contribute to broaden the potential of Brassica oils for industrial applications.

QTL Identification for Fatty Acid Content in Rapeseed ( Brassica napus L.)

A segregation population BC 1F 1 of rapeseed ( Brassica napus L.), derived from a cross between a low erucic acid content line APL01 and a high erucic acid content variety M083, was used to construct the genetic map and identify auantitave trait loci (QTLs) linked to main fatty acid composition in rapeseed. The genetic map containing 19 linkage groups was constructed with 251 markers of RAPD, SSR, and SRAP. By means of WinQTLCart scanning, 5 QTLs linked to palmitic acid (C16:0) content were identified, which were located on linkage groups N3, N8, N10, and N13, respectively. The main-effect QTLs qPA8-1 and qPA13 linked to palmatic acid content in rapeseed explained 11.31% and 14.47% of the palmitic acid content variation in the segregation population BC 1F 1, respectively. Three QTLs linked to stearic acid (C18:0) content were identified, which were located on the linkage groups N1, N8, and N16. The main-effect QTL qST16 accounted for 12.22% of phenotypic variation. Two QTLs, qOL8 and qOL13, the main-effect QTLs linked to oleic acid (C18:1) content, were located in the region of m11e37b– A0226Ba267 on linkage group N8 and m18e46– m20e25a on N13. These QTLs accounted for 11.73% and 27.14% of phenotypic variation, respectively. Three QTLs linked to linoleic acid (C18:2) content were identified, and the main-effect QTL qLI8-1 accounted for 13.25% of phenotypic variation. Three QTLs, qLN1, qLN8, and qLN11, linked to linolenic acid (C18:3) content, were identified, but they had small effects on C18:3 and could be regarded as minor-QTLs. Four QTLs were linked to eicosenoic acid (C20:1) content, and three of them, qEI8-1, qEI8-2, and qEI13, were main-effect QTLs, accounting for 12.20%, 10.22%, and 11.14% of phenotypic variation, respectively. Two main-effect QTLs linked to erucic acid (C22:1) content, qER8 and qER13, were located in the region of m11e37b– A0226Ba267 on linkage group N8 and A0301Bb398– m18e46 on N13, accounted for 16.74% and 31.32% of phenotypic variation, respectively. The main-effect QTLs linked to fatty acid content, which were located in the region near marker m11e27b on linkage group N8 and m18e46 on linkage group N13, could be used in marker-assisted selection in fatty acid improvement in rapeseed.

Marker‐assisted increase of genetic diversity in a double‐low seed quality winter oilseed rape genetic background

AbstractGeneration of novel genetic diversity for maximization of heterosis in hybrid production is a significant goal in winter oilseed rape breeding. Here, we demonstrate that doubled haploid (DH) production using microspore cultivation can simultaneously introgress favourable alleles for double‐low seed quality (low erucic acid and low‐glucosinolate content) into a genetically diverse Brassica napus genetic background. The DH lines were derived from a cross between a double‐low quality winter rapeseed variety and a genetically diverse semisynthetic B. napus line with high erucic acid and high glucosinolates (++ quality). Twenty‐three low‐glucosinolate lines were identified with a genome component of 50–67% derived from the ++ parent. Four of these lines, with a genome component of 50–55% derived from the ++ parent, also contained low erucic acid. Heterosis for seed yield was confirmed in test‐crosses using these genetically diverse lines as pollinator. The results demonstrate the potential of marker‐assisted identification of novel genetic pools for breeding of double‐low quality winter oilseed rape hybrids.

Mapping QTL controlling fatty acid composition in a doubled haploid rapeseed population segregating for oil content

Increasing oil content and improving the fatty acid composition in the seed oil are important breeding goals for rapeseed (Brassica napus L.). The objective of the study was to investigate a possible relationship between fatty acid composition and oil content in an oilseed rape doubled haploid (DH) population. The DH population was derived from a cross between the German cultivar Sollux and the Chinese cultivar Gaoyou, both having a high erucic acid and a very high oil content. In total, 282 DH lines were evaluated in replicated field experiments in four environments, two each in Germany and in China. Fatty acid composition of the seed oil was analyzed by gas liquid chromatography and oil content was determined by NIRS. Quantitative trait loci (QTL) for fatty acid contents were mapped and their additive main effects were determined by a mixed model approach using the program QTLMapper. For all fatty acids large and highly significant genetic variations among the genotypes were observed. High heritabilities were determined for oil content and for all fatty acids (h 2 = 0.82 to 0.94), except for stearic acid content (h 2= 0.38). Significant correlations were found between the contents of all individual fatty acids and oil content. Closest genetic correlations were found between oil content and the sum of polyunsaturated fatty acids (18:2 + 18:3; r G = −0.46), the sum of monounsaturated fatty acids (18:1 + 20:1 + 22:1; r G = 0.46) and palmitic acid (16:0; r G = −0.34), respectively. Between one and eight QTL for the contents of the different fatty acids were detected. Together, their additive main effects explained between 28% and 65% of the genetic variance for the individual fatty acids. Ten QTL for fatty acid contents mapped within a distance of 0 to 10 cM to QTL for oil content, which were previously identified in this DH population. QTL mapped within this distance to each other are likely to be identical. The results indicate a close interrelationship between fatty acid composition and oil content, which should be considered when breeding for increased oil content or improved oil composition in rapeseed.

Cloning of fatty acid elongase1 gene and molecular identification of A and C genome in Brassica species

The fatty acid elongase 1 (FAE1) genes of Brassic napus were cloned from two cultivars, i.e. Zhongshuan No. 9 with low erucic acid content, and Zhongyou 821 with high erucic acid content, using the degenerate PCR primers. The sequence analysis showed that there was no intron within the FAE1 genes. The FAE1 genes from Zhongyou 821 contained a coding sequence of 1521 nucleotides, and those cloned from Zhongshuan No. 9 contained a 1517 bp coding sequence. Alignment of the FAE1 sequences from Brassica rapa, B. oleracea and B. napus detected 31 single nucleotide polymorphic sites (2.03%), which resulted in 7 amino-acid substitutions. Further analysis indicated that 19 SNPs were genome-specific, of which, 95% were synonymous mutations. The nucleotide substitution at position 1217 in the FAE1 genes led to a specific site of restricted cleavage. An AvrII cleavage site was present only in the C genome genes and absent in the A genome FAE1 genes. Digestion profile of the FAE1 sequences from B. rapa, B. oleracea and B. napus produced with AvrII confirmed that the FAE1 genes of B. oleracea origin was recognized and digested, while that of B. rapa origin could not. The results indicated that by AvrII cleavage it was possible to distinguish B. rapa from B. oleracea and between the A and C genome of B. napus. In addition, the FAE1 genes could be used as marker genes to detect the pollen flow of B. napus, thus providing an alternative method for risk assessment of gene flow.

Process Study on Enzymatic Hydrolysis of Crambe Oil for Erucic Acid Isolation

High erucic acid (HEA) seed oils can be processed enzymatically to produce biodiesel and erucic acid (EA), a valuable industrial feedstock. This study aimed to conduct a research on an effective reaction pathway to isolate EA from other fatty acids in HEA oils utilizing appropriate lipase specificities. Crambe oil was chosen as the model working feedstock. Rhizomucor miehei lipase was chosen to selectively hydrolyze crambe oil to liberate EA from the HEA oil directly into free EA. The effects of reaction parameters, including water content, lipase concentration, mixing intensity, and reaction temperature, were studied. Experimental results of an orthogonal design showed that the effect of process parameters was significant for the reaction rate, but insignificant for the reaction selectivity. Further statistical analysis revealed that lipase concentration had the most significant effect on the reaction rate, while water content showed a negative effect on the hydrolysis. Individual effects of aqueous phase ratio, initial lipase concentration, and mixing intensity were further investigated separately at the optimal lipase activity temperature. Results showed that water played a role mainly in affecting the specific interfacial area in the heterogeneous process of crambe oil hydrolysis. The interfacial reaction rate increased with the increase in initial lipase concentration, but was limited by a critical value. Mixing intensity affected the hydrolysis to a certain extent and then leveled off due to the lack of further size reduction of the discrete phase.

"Sincron": A new Brassica carinata cultivar for biodiesel production

The recent rapid increase of petrol price due to the rising world demand for energy and the rapid depletion of fossil fuels calls for a diversification of energy sources, with particular reference to liquid fuels, gasoline and diesel oil. Diesel fuel in particular is fundamental for human and trade transport. Biodiesel, produced by a simple processing of oil from animal fat and/or oilcrops, could represent an interesting alternative, both pure or mixed with diesel oil. Biodiesel remains interesting even when it becomes clear that it cannot provide a complete substitution for diesel oil use. In tropical areas oil palm, cotton oil, etc. could represent valid sources of vegetable oil, while in temperate areas, rape, soybean and sunflower now represent possible adapted biodiesel producers. However, there is a need to identify other oil crop species, fall sown, not needing irrigation but exhibiting high potential oil productivity. Among the members of the genus Brassica, Brassica carinata, an allopolyploid species coming from natural crosses of B. nigra B. oleracea, originated in Ethiopia, could be of interest for biodiesel production. Being a semi-wild species, but domesticated for indehiscent pod, fall or spring seeded in our conditions, with good growth, Brassica carinata could be a candidate for biodiesel production. We introduced several lines/populations, selected with particular reference to winter survival (particularly in North and Central Italy), high biomass and seed production and good adaptation to marginal soils. The collection and selection program started in the 1990s, with lines obtained from ENEA, Koipesol, India, Germany, Netherlands, etc. After the preliminary screening for agronomic performance, several lines were identified and selected for increased seed and biomass production. The best-performing line, selected from a population coming from North India, was tested in north, central and south Italy, with interesting results. The line, now called "Sincron" for its synchronic ripening, should be seeded in the fall, after good soil preparation to ensure high resistance to winter conditions, in order to profit from winter rains and from long growing cycle. In good conditions, Sincron reaches 1.50-1.70 m height, seed production of 4.0-4.8 t/ha, seed oil content of 33%-35%, with high erucic acid content (47%) and good technological characteristics for biodiesel production. A program involving some 35.000 ha has been proposed in Sicily for production of both biodiesel and electric power from the biomass, while the pres ence of glucosinolates in the cake could be used for control of nematodes in greenhouses and protected cultivations, after the ban of methyl bromide. .

Red River 1852 Roundup Ready™ high erucic acid, low glucosinolate summer rape

Red River 1852 summer rape (Brassica napus L.) is the world’s second Roundup Ready™ high erucic acid, low glucosinolate cultivar. It has a 3% yield advantage over Reston high erucic acid, low glucosinolate summer rape in the mid-season zone, is 26 g kg-1 higher in seed oil content than Reston, is equal to Reston in meal protein content and is adapted to all B. napus growing regions of western Canada. Key words: Rape, Roundup Ready™, high erucic acid, low glucosinolate, cultivar description

Red River 1826 Roundup Ready™ high erucic acid, low glucosinolate summer rape

Red River 1826 summer rape (Brassica napus L.) is the world’s first Roundup Ready™ high erucic acid, low glucosinolate cultivar. It has an average 1% yield advantage over Reston high erucic acid, low glucosinolate summer rape, is 39 g kg-1 higher in seed oil content than Reston, 13 g kg-1 higher in meal protein content than Reston, and is adapted to the southern B. napus growing regions of western Canada. Key words: Rape, Roundup Ready™, high erucic acid, low glucosinolate, cultivar description

Genetic diversity of Brassica napus L. Germplasm from China and Europe assessed by some agronomically important characters

The genetic diversity and relationships among 63 rapeseed accessions, including 34 Chinese, 22 Czech, 2 Swedish, 2 German, one French and 2 Canadian accessions, were evaluated by nine agronomically important characters in the field at Yangling, Shaanxi, China. Significant differences between Chinese and European group in plant height, setting position of the first primary branch, number of siliques of the terminal raceme, thousand seed weight and seed yield per plant were detected. There were significant variations in nine agronomic characters among the tested rapeseed accessions. Ward’s minimum variance cluster analysis based on Mahalanobis distances on the raw data of nine agronomic characters clearly separated the European accessions from the Chinese ones. However, the Chinese accessions with erucic acid free and/or low glucosinolates could not be separated from those Chinese accessions with both high erucic acid and glucosinolates. In general, cluster analysis of the 63 accessions based on the selected agronomic characters was consistent with known pedigree information and geographic origin, as well as the previous RAPD results of these accessions. The European rapeseed could be important germplasm resources for enriching the genetic background of Chinese rapeseed, and vice versa.

Breeding high-stearic oilseed rape (Brassica napus) with high- and low-erucic background using optimised promoter-gene constructs

Seed lipids of oilseed rape (Brassica napus) usually contain small proportions (<3%) of stearic acid. The objective of this study was to increase the content of stearic fatty␣acid in rapeseed oil. An antisense down-regulation of the endogenous stearoyl-ACP desaturase (SAD) catalysing the reaction step from stearic to oleic acid in two different genetic backgrounds was studied. The result of down-regulation of the SAD yielded an about 10-fold increase of stearic acid from 3.7% up to 32% in single seeds of transgenic low-erucic acid rapeseed (LEAR), while high-erucic acid rapeseed (HEAR) showed a 4-fold increase of C18:0 from 1% up to 4%. It could be shown in pooled T2 seed material of LEAR rapeseed, that the stearic acid content is highly correlated with the down-regulation of SAD as indicated by the␣stearate desaturation proportion (SDP). The importance of the promoter strength for the alteration of a trait was confirmed in this study as no change in the fatty acid composition of transgenic plants was achieved with gene constructs controlled by the weak FatB4 seed-specific promoter from Cuphea lanceolata.