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1.
Six accessions belonging to four subspecies of Brassica rapa, including three accessions of B. rapa subsp. sylvestris, were crossed with B. oleracea subsp. alboglabra in order to develop a series of synthetic B. napus lines with a common C genome but contrasting A genomes. Different A genomes had significant effects on the efficiency of B. napus resynthesis and the sexual compatibility of the synthetic lines with oilseed rape cultivars. The synthetic lines were used to investigate the effect of A genome substitution on the resistance of B. napus to infection by Leptosphaeria maculans, and to explore the potential for the use of wild forms of B. rapa in oilseed rape breeding programmes. Synthetic lines derived from two wild accessions of B. rapa, and their F1 hybrids with oilseed rape cultivars, expressed high levels of resistance to L. maculans in glasshouse experiments. One of these lines also expressed high levels of resistance in field experiments in England and Australia when exposed to a genetically diverse pathogen population. All other synthetic lines and cultivars were highly susceptible in both glasshouse and field experiments. F1 hybrids between oilseed rape cultivars and synthetic lines derived from B. rapa subsp. chinensis were significantly more susceptible than either parent.  相似文献   

2.
Generation 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.  相似文献   

3.
M. H. Rahman 《Plant Breeding》2002,121(4):357-359
The fatty acid composition of seed oil of four interspecific hybrids, resulting from crosses between zero erucic acid Brassica rapa (AA), and high erucic acid Brassica alboglabra/Brassica oleracea (CC) and Brassica carinata (BBCC), void of erucic acid genes in their A‐genomes was examined. The erucic acid content in resynthesized Brassica napus (AACC) lines derived from these crosses was only about half that of the high erucic acid CC genome parents, indicating equal contributions of the two genomes to oil (fatty acid) synthesis and accumulation. The differences in C18 fatty acid synthesis between the parents were also evident in the resulting resynthesized B. napus plants. Hexaploid Brassica plants of the genomic constitution AABBCC, in which the AA genome was incapable of erucic acid synthesis, had lower erucic acid contents than the B. carinata (BBCC) parent. This is plausible considering the fact that the zero erucic acid AA genome contributes to oil synthesis in AABBCC plants, thus reducing erucic acid content.  相似文献   

4.
The allopolyploidization event that created cultivated oilseed rape Brassica napus L, followed by intense breeding, reduced its genetic diversity. Resynthesized (RS) B. napus L. obtained by interspecific hybridization between genotypes of B. rapa L. and B. oleracea L. can be a valuable source for broadening genetic diversity in cultivated oilseed rape. In this study, we determined the extent of DNA polymorphism among natural accessions of oilseed rape, resynthesized B. napus, their parental species and double-low quality semi-RS lines carrying the Rfo gene. Using 10 selected primer combinations, 522 polymorphic AFLP markers were scored in the complete set of 100 Brassica sp. To detect relationships between these genotypes, a cluster analysis was performed using the Jaccard’s distance. Resynthesized allopolyploids clustered directly between their diploid parents. Cultivated accessions of oilseed rape created a compact group away from resynthesized allopolyploids as well as semi-RS lines. The natural oilseed rape group, which consists of 49 cultivars and breeding lines of oilseed rape, is characterized by lower genetic diversity than the group of 33 accessions of resynthesized oilseed rape, and the analysis showed that the double-low quality semi-RS lines represent a specific genetic variation of B. napus. The de novo resynthesized B. napus lines and the semi-RS lines of double-low quality generated from them, provide a significant opportunity for enrichment the gene pool of oilseed rape.  相似文献   

5.
W. K. Heneen  K. Brismar   《Plant Breeding》2001,120(4):325-329
Most oilseed rape, Brassica napus, cultivars are black‐seeded. The progenitor species, Brassica rapa, has either yellow or black seeds, while known cultivars of the other progenitor species Brassica oleracea/alboglabra have black seeds. To determine which chromosomes of B. alboglabra are carriers of seed colour genes, B. rapaalboglabra monosomic addition lines were produced from a B. napus resynthesized from yellow‐seeded B. rapa and brown/black‐seeded B. alboglabra. Eight out of nine possible lines have been developed and transmission frequencies of the alien chromosomes were estimated. Three B. alboglabra chromosomes in three of these lines influenced seed colour. B. rapa plants carrying alien chromosome 1 exhibited a maternal control of seed colour and produced only brown seeds, which gave rise to plants with either yellow or brown seeds. However, B. rapa plants carrying alien chromosome 4 or another as yet unidentified alien chromosome exhibited an embryonal control of seed colour and produced a mixture of yellow and brown seeds. The yellow seeds gave rise to yellow‐seeded plants, while the brown seeds gave rise to plants that yielded a mixture of yellow and brown seeds, depending on the absence or presence, respectively, of the B. alboglabra chromosome. Consequently, both maternal and embryonal control of seed colour are expected to contribute to the black‐seeded phenotype of oilseed rape.  相似文献   

6.
Two hundred and ninety‐nine accessions representing 11 cultivar groups of Brassica oleracea and eight additional accessions of the wild species B. cretica, B. incana, B. insularis and B. villosa were screened for resistance to Verticillium wilt. A disease index (DI) was calculated for each accession, and a correction of the DI was carried out to compensate for a fluctuating infection level between 11 independent trials. A total of 235 , or 77% of the accessions tested, had a DIcorr less or equal to the oilseed rape cv. ‘Express’ (DIcorr= 2.81), the reference cultivar. Only one accession of the wild species, B. incana, showed an enhanced level of resistance (DIcorr= 2.01). Twenty‐four accessions, distributed over eight cultivar groups of B. oleracea were selected for subsequent crosses involving B. rapa. Hybrid plants with 14 accessions were resultant and seed was obtained from crosses where the cultivar groups acephala, alboglabra, botrytis, capitata, gemmifera, italica and sabellica were used as female parents. When progeny of the produced resynthesized rapeseed lines were evaluated for Verticillium wilt resistance, three lines showed a significantly lower disease index (P ≥ 0.01) compared with the cv. ‘Express’. This source of resistance is now being crossed to advanced breeding material of oilseed rape.  相似文献   

7.
Brassica napus is a leading oilseed crop throughout many parts of the world. It is well adapted to long day photoperiods, however, it does not adapt well to short day subtropical regions. Short duration B. napus plants were resynthesized through ovary culture from interspecific crosses in which B. rapa cultivars were reciprocally crossed with B. oleracea. From five different combinations, 17 hybrid plants were obtained in both directions. By self-pollinating the F1 hybrids or introgressing them with cultivated B. napus, resynthesized (RS) F3 and semi-resynthesized (SRS) F2 generations were produced, respectively. In field trial in Bangladesh, the RS B. napus plants demonstrated variation in days to first flowering ranging from 29 to 73 days; some of which were similar to cultivated short duration B. napus, but not cultivated short duration B. rapa. The RS and SRS B. napus lines produced 2–4.6 and 1.6–3.7 times higher yields, respectively, as compared to cultivated short duration B. napus. Our developed RS lines may be useful for rapeseed breeding not only for subtropical regions, but also for areas such as Canada and Europe where spring rapeseed production can suffer from late spring frosts. Yield and earliness in RS lines are discussed.  相似文献   

8.
N. N. Roy 《Euphytica》1984,33(2):295-303
Summary Complete resistance to Leptosphaeria maculans, the cause of blackleg of oilseed rape (Brassica napus), was transferred from B. juncea to B. napus through an interspecific cross. B. juncea-type complete resistance (JR) was recognized first in one F3 progeny (OnapJR) by the absence of leaf-lesions on seedlings and canker-free adult plants. The commercially important characters of B. napus were retained in advanced lines of OnapJR, which combined JR with low erucic acid levels (<0.5%), high seed yield and variable maturity dates.JR appeared to be inherited as a major gene or genes. Segregation for resistance and susceptibility contintied to occur during later generations of selection of OnapJR. JR was readily transferred from OnapJR to other suitable B. napus cultivars or lines with partial resistance to blackleg and resulted in highly vigorous carly generation selections adapted to cold, wet situations along with complete resistance to blackleg.  相似文献   

9.
The Inheritance of Aliphatic Glucosinolates in Brassica napus   总被引：2，自引：0，他引：2  
The inheritance of aliphatic glucosinolates was studied in crosses between synthetic B. napus lines and oilseed rape cultivars. Six unlinked loci are described which determine the aliphatic glucosinolate profile of B. napus. One locus regulates the presence or absence of propyl glucosinolates, while another regulates the expression of pentyl glucosinolates. Two loci regulate the removal of the terminal H3CS-group from the amino acid derivative to produce alkenyl glucosinolates as opposed to methylthioalkyl and methylsulphinylalkyl glucosinolates, regardless of the length of the alkyl chain. Likewise, another two loci regulate the hydroxylation of both butenyl and pentenyl glucosinolates. The functional alleles at one of the hydroxylation loci results in significantly more hydroxylation than those at the other locus. The large number of aliphatic glucosinolates which have been described in Brassica thus results from an interaction between genes which regulate side chain elongation and genes which modify the structure of the side chain, regardless of its length. The implications of this study for the biosynthesis of aliphatic glucosinolates, the origin of B. napus and the potential to manipulate the leaf and seed glucosinolate profile of oilseed rape are discussed.  相似文献   

10.
Resynthesized (RS) rapeseed generated from interspecific hybridization between suitable forms of Brassica rapa L. (syn. campestris; genome AA, 2n = 20) and B. oleracea L. (CC, 2n = 18) represents a potentially important resource to expand genetic diversity in the narrow gene pool of oilseed rape (B. napus L., AACC, 2n = 38). In this study 165 RS rapeseed lines originating from crosses between an Indian Yellow Sarson (B. rapa ssp. trilocularis) and five different cauliflower (B. oleracea convar. botrytis) cultivars were studied using amplified fragment length polymorphism (AFLP) markers and their genetic diversity was compared in relationship to an assortment of 40 diverse spring oilseed and fodder rape varieties. Using three AFLP primer combinations, a total of 467 polymorphic bands were scored. Cluster analysis allowed differentiation among the different RS lines, which, as expected, were genetically highly divergent from the cultivars. The genetic diversity of the material is discussed in relation to its morphological variability with a view to the implementation of RS lines in oilseed rape breeding.  相似文献   

11.
C. M. Lu    B. Zhang    F. Kakihara  M. Kato 《Plant Breeding》2001,120(5):405-410
Fifteen lines of Brassica napus were resynthesized via ovule culture through 24 interspecific crosses between four Brassica oleracea and three Brassica campestris accessions. The degree of success in the interspecific crosses was significantly influenced by maternal genotypes. The interspecific hybrid production rate (HPR) varied with combinations from 0 to 76.9%, with a mean HPR of 24.7% for the crosses with B. campestris as the female parent and 6.9% for the crosses with B. oleracea as female parent. Twenty‐four crosses between seven natural and six resynthesized B. napus gave, on average, 10.3 seeds per pod, and ranged from 1.2 to 22.0 seeds per pod, depending on genotypes of both parents. Resynthesized lines of B. napus showed high erucic acid content and variable content of linolenic acid, ranging from 3.4% to 9.9%. The fatty acid composition in hybrid seeds between natural and resynthesized B. napus was dominated by the embryo genotypes; an additive mode was shown for erucic acid and positive over‐dominance for linolenic acid content.  相似文献   

12.
Resistance responses of resynthesized Brassica napus lines to infection with Plasmodiophora brassicae were investigated. Lines that were derived from interspecific crosses between clubroot-resistant B. rapa and resistant B. oleracea exhibited very broad and effective resistance in both greenhouse and field tests. When clubroot resistance was introduced into resynthesized lines from the B. oleracea parent only, the plants were mainly susceptible. Interspecific hybrids from the most resistant parental genotypes, i.e. B. campestris ECD-04 and the B. oleracea cultivars ECD-15 or ‘Bohmerwaldkohf’, were used to initiate a B. napus resistance-breeding programme. These artificial rapeseed lines were resistant to isolates that were virulent on all B. napus differential lines and/or parental lines. Preliminary segregation analysis suggests that their resistance is due to at least two dominant and unlinked genes. In some cases progenies from selfed resynthesized plants exhibited resistance reactions that differed from those of the parental hybrid plant; this may have been the result of cytological instability.  相似文献   

13.
C. M. Lu    B. Zhang    L. Liu  M. Kato 《Plant Breeding》2004,123(5):495-496
The effect of genome composition and cytoplasm on petal size was studied in Brassica. Two accessions of Brassica rapa (2n = 20, AA) were reciprocally crossed with three accessions of Brassica oleracea (2n =18, CC) to produce resynthesized B. napus (2n = 38, AACC or CCAA) and sesquidiploids (2n = 29, AAC or CAA). Petal size was measured and compared among diploids (AA and CC), sesquidiploids (AAC and CAA) and amphidiploids(AACC and CCAA). The results showed that petal size is a genome‐dependent and highly heritable character. The heritability of petal length is as high as 96.3%. The addition of each C‐genome to the AA genomic background increased the petal length by 4‐5 mm. Cytoplasm of B. oleracea showed a positive effect on petal length by about 1.3 mm over that of B. rapa. Petal width was positively correlated with petal length at a highly significant level (r= 0.806, df = 81). Resynthesized B. napus (AACC) showed significantly larger flower petals than natural rapeseed cultivars (AACC).  相似文献   

14.
Synthetic lines of Brassica napus were derived by combining the genomes of B. atlantica and B. oleracea var. alboglabra, which were respectively resistant and susceptible to foliar infection by Leptosphaeria maculans, with a susceptible line of B. rapa. Resistance was expressed in the synthetic lines containing the genome of B. atlantica. The high levels of alkenyl glucosinolates which occur in leaves of B. atlantica, and which have been implicated in disease resistance, were also expressed within the synthetic lines, although the dominant glucosinolate had changed from sinigrin to glucobrassicanapin. Disease resistance and glucosinolate profiles did not co-segregate in F2 progeny from crosses between the synthetic lines.  相似文献   

15.
Low erucic acid (LEA) rapeseed, which has accumulated mutant fatty acid elongase genes at the BnFAE1.1 and BnFAE1.2 loci of the A- and C-genome, respectively, is an important oilseed crop. Short growing turnip rape (B. rapa) is also important as a catch crop in the continuous cropping of rice in Asia but there is no LEA B. rapa cultivar for cultivation in South Asia. In order to develop LEA turnip rape cultivars, high erucic acid turnip rape cultivars were interspecifically crossed as recurrent parents to a canola quality rapeseed. In the meantime, we monitored incorporation of the mutant bnfae1.1 (e1) gene into A-genome of turnip rape, using a dCAPS primer pair, which can amplify PCR fragment only for the mutant e1 gene from A-genome. The early backcross progenies showed poor seed set, but which was improved in advanced progenies. Finally, homozygous e1e1 genotypes were established in the selfed progenies of BC2–BC3, and their LEA content was confirmed by gas-chromatography analysis. Our results and promising lines will contribute to LEA-trait selection in turnip rape and rapeseed breeding.  相似文献   

16.
R. Wang    V. L. Ripley    G. Rakow 《Plant Breeding》2007,126(6):588-595
Pod shatter susceptibility was investigated in Brassica napus germplasm and shatter resistant species of B. juncea and Sinapis alba. The comparisons were made by measuring seed yield in field plots, detached pod rupture energy (RE) and the half‐life of pod‐opening. Pod shatter resistance was significantly greater in B. napus lines derived from interspecific hybridizations of B. napus with B. rapa, B. carinata and B. juncea, than common B. napus cultivars. While these lines exhibited no significant difference in resistance to pod shatter than B. juncea, an entry of S. alba had no yield loss caused by pod shatter. Resistance to pod shatter was characterized in the field as little or no yield loss after full maturity, delayed shattering in time, and stable yield performance under variable climatic conditions during pod maturity. Yield loss caused by pod shatter ranged from a low of 4% for the B. juncea cv. ‘AC Vulcan’ to a high of 61% for the black seeded B. napus line DH12075 in 2‐year field trials after 1 month maturity. Pod shatter resistance was not significantly associated with specific plant and pod morphological traits, except pod length (P = 0.005) in tested materials. Field visual scores of pod shatter through inspections of average pod shatter per plant within plots were highly correlated with plot yield loss. Indoor quantitative evaluations of pod strength using a pendulum machine to measure pod RE and random impact test to measure half‐life of pod‐opening resistance were highly correlated with field yield loss. Multiple evaluations of pod shatter in method and in time after pod maturity are recommended for reliable evaluation of pod shatter resistance.  相似文献   

17.
Development of yellow-seeded Brassica napus of double low quality   总被引：3，自引：0，他引：3  
M. H. Rahman    M. Joersbo  M. H. Poulsen   《Plant Breeding》2001,120(6):473-478
Two yellow‐seeded white‐petalled Brassica napus F7 inbred lines, developed from interspecific crosses, containing 26–28% emcic acid and more than 40 μmol glucosinolates (GLS)/g seed were crossed with two black/dark brown seeded B. napus varieties of double low quality and 287 doubled haploid (DH) lines were produced. The segregation in the DH lines indicated that three to four gene loci are involved in the determination of seed colour, and yellow seeds are formed when all alleles in all loci are in the homozygous recessive state. A dominant gene governed white petal colour and is linked with an erucic acid allele that, in the homozygous condition, produces 26–28% erucic acid. Four gene loci are involved in the control of total GLS content where low GLS was due to the presence of recessive alleles in the homozygous condition in all loci. From the DH breeding population a yellow‐seeded, yellow‐petalled, zero erucic acid line was obtained. This line was further crossed with conventional B. napus varieties of double low quality and, following pedigree selection, a yellow seeded B. napus of double low quality was obtained. The yellow seeds had higher oil plus protein content and lower fibre content than black seeds. A reduction of the concentration of chromogenic substances was found in the transparent seed coat of the yellow‐seeded B. napus.  相似文献   

18.
Brassica rapa L. is a genetically diverse parent species of the allotetraploid species, oilseed rape (B. napus) and a potential source of drought tolerance for B. napus. We examined the effect of a 13‐day drought stress period during the early reproductive phase, relative to a well‐watered (WW) control, on subsequent growth and development in nine accessions of B. rapa and one accession of Brassica juncea selected for their wide morphological and genetic diversity. We measured leaf water potential, stomatal conductance, water use, and leaf and bud temperatures during the stress period and aboveground dry weight of total biomass at maturity. Dry weight of seeds and reproductive tissue were not useful measures of drought tolerance due to self‐incompatibility in B. rapa. The relative total biomass (used as the measure of drought tolerance in this study) of the 10 accessions exposed to drought stress ranged from 47 % to 117 % of the WW treatment and was negatively correlated with leaf‐to‐air and bud‐to‐air temperature difference when averaged across the 13‐day stress period. Two wild‐type (B. rapa ssp. sylvestris) accessions had higher relative total and non‐reproductive biomass at maturity and cooler leaves and buds than other types. We conclude that considerable genotypic variation for drought tolerance exists in B. rapa and cooler leaves and buds during a transient drought stress in the early reproductive phase may be a useful screening tool for drought tolerance.  相似文献   

19.
Brassica napus is an important oil species with short history and narrow genetic background. Interspecific hybrids from crosses between B. oleracea and different B. rapa were obtained. We found the hybrids with white petal resembling B. oleracea, the flavonoid and phenolic content decreased in hybrids, agreeing with the expressional changes of flavonoid biosynthesis genes. Seed coat of hybrids resembled diploid parents, or partly resembled to each parent with a clear outline. The palisade layer in hybrids was thicker than parents, with similar pigment accumulation as B. oleracea but more than B. rapa. Differentially sized protein bodies (PBs) were found in hybrids. The radical and inner cotyledon of all hybrids were identified with larger but less PBs than parents. The average size of PBs in outer cotyledon of resynthesized B. napus was also larger than parents, but the number of PBs was not significantly reduced. The phenotypic and seed structural variations after polyploidization of B. napus would be interesting for genetic broadening and breeding of rapeseed.  相似文献   

20.
Ethiopian mustard (Brassica carinata Braun) is a potential oil crop in which genes for low erucic acid content of the seed oil have not yet been found. In order to solve this problem the potential of rapeseed (B. napus L.) varieties as a source of these genes has been tested. Reciprocal F1 hybrids between B. carinata and a low erucic acid variety of B. napus, F2, and backcrosses with B. carinata were obtained. The fatty acid composition was determined in half seeds of F1 and segregating generations from reciprocal interspecific crosses. The genetic analysis indicated that the erucic acid content of the seed oil of B. carinata is controlled by two genes with no dominance and additive in action.  相似文献   

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