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1.
Initial studies have shown variable resistance in Brassica fruticulosa to the aphid Brevicoryne brassicae The aim of this work was to fix high levels of resistance to B. brassicae in true breeding lines of B. fruticulosa and obtain data on the genetic control of resistance. Plants from initially variable B. fruticulosa accessions were selfed to produce inbred resistant and susceptible lines that were studied in three separate experiments to determine the extent to which resistance to B. brassicae had been fixed. Results from three experiments using successive generations of resistant and susceptible inbred lines showed that continued selection resulted in resistant inbred lines that supported an average of three aphids per plant compared with an average of 96 aphids per plant for susceptible inbred lines. Data collected from an experiment determining the resistant phenotype of lines including the selfed progenies and the F1 and F2 progeny of a cross between resistant and susceptible individual plants indicated that the resistance was not controlled by a single gene.  相似文献   

2.
Summary A wide range of cultivated brassica accessions including broccoli, Brussels sprouts, Chinese cabbage, cauliflower, collard, kale and swede material was tested against the cabbage aphid, Brevicoryne brassicae, at HRI, Wellesbourne in the field and laboratory in both 1992 and 1993. In the field, B. brassicae attack was assessed as the proportion of infested plants and the numbers of aphid colonies present. In the laboratory, aphid performance was measured in terms of the pre-reproductive and reproductive period, population increase, and insect mortality. Interpretation of the data was facilitated by plotting sorted accession means against normal order statistics. This statistical approach indicated the spread of variation amongst the accessions and permitted identification of extremes. Partial levels of antixenosis resistance were discovered in red brassicas. Glossy accessions of cabbage and cauliflower possessed antixenosis and antibiosis resistance that lasted throughout the season of crop growth in the field. Other accessions were shown to withstand aphid attack and therefore possessed tolerance. The laboratory studies provided information on mechanisms of antibiosis resistance. The potential value of the different sources of resistance is discussed.  相似文献   

3.
Clubroot, caused by Plasmodiophora brassicae Woron, is a major disease of cruciferous crops and few sources of resistance have been detected and genetically studied in the Brassica oleracea species. In this study, two diallel mating systems using resistant kale lines and susceptible cauliflower lines were performed. Resistance was assessed from a disease index evaluated on young plants artificially inoculated with local isolates of the parasite. Both general and specific combining ability effects (GCA and SCA) and partly reciprocal effects were demonstrated. Resistance inheritance was, however, characterized by a predominance of additive genetic effects (GCA). Three groups of parent lines could be separated; kale lines with very high resistance, kale lines with intermediate resistance and susceptible cauliflower lines. In the two kale groups, two genetically different resistance types were suggested and various recurrent selection procedures are proposed following the diallel results.  相似文献   

4.
Wild Brassica species and associated breeding lines were evaluated for their resistance to Delia radicum, the cabbage root fly, in the field in 1993 and in the field, glasshouse and laboratory in 1996. High levels of antibiosis resistance were discovered in the field in 1993 in Brassica fruticulosa, B. incana, B. villosa and B. spinescens and confirmed in the field in 1996 while two B. oleracea accessions and the susceptible control Brussels sprouts variety, ‘Oliver’, were highly susceptible. No D. radicum pupae were found in the soil around the roots of B. fruticulosa and B. spinescens at the end of the season. All the Brassica species were attractive to egg-laying by D. radicum in the field and in a laboratory experiment and therefore lacked antixenosis resistance. In a series of glasshouse experiments, Brassica species and breeding lines were inoculated with D. radicum eggs supplied from a laboratory culture and the effects of larval feeding on plants recorded. Brassica incana, B. fruticulosa and B. spinescens were highly resistant, most plants surviving, whilst B. macrocarpa and B. villosa were moderately resistant as were two F1 lines bred from a cross between B. macrocarpa and B. oleracea. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

5.
Interspecific hybrid plants and backcross 1 (BC1) progeny were produced through sexual crosses and embryo rescue between Brassica carinata accession PI 360883 and B. oleracea cvs Titleist’and‘Cecile’to transfer resistance to powdery mildew to B. oleracea. Four interspecific hybrids were obtained through application of embryo rescue from crosses with B. carinata as the maternal parent, and their interspecific nature confirmed through plant morphology and random amplified polymorphic DNA (RAPD) analysis. Twenty‐one BC1 plants were obtained through sexual crosses and embryo rescue although embryo rescue was not necessary to produce first backcross generation plants between interspecific hybrids and B. oleracea. All interspecific hybrids and eight of the BC1 plants were resistant to powdery mildew.  相似文献   

6.
甘蓝(Brassica oleracea var.)是重要的十字花科芸薹属蔬菜,但生产中常遭受蚜虫危害,鉴定抗虫资源并了解其抗虫机制是抗虫育种的重要基础。课题组前期征集到1份周身覆盖浓密表皮毛的野生甘蓝(B.incana),为调查该材料是否具有蚜虫抗性,并明确其抗性是否与表皮毛有关,本研究利用该有毛野生甘蓝与1份无毛芥蓝(B.alboglabra)杂交,对双亲及其F2:3家系中有毛和无毛家系进行室内蚜虫接种发现,蚜虫在无表皮毛甘蓝上的平均产卵数(36.7枚)和存活天数(22.2 d)均显著高于有表皮毛甘蓝(平均产卵8.1枚,平均存活13.1 d)。为进一步明确该野生甘蓝对蚜虫是否具有化学毒杀或排拒作用,采用有毛和无毛甘蓝叶片的浸提液对蚜虫进行胃杀、触杀和拒食性调查发现,2种浸提液对蚜虫均无胃杀和触杀作用,但有毛甘蓝浸提液对蚜虫存在一定的趋避作用。表明野生甘蓝B.incana对蚜虫的抗性一方面源于其表皮毛的物理阻碍,另一方面与其体内化学物质的趋避作用有关。  相似文献   

7.
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   

8.
A total of 240 kale, 38 cabbage and 126 winter cauliflower French landraces from the B. oleracea genepool of INRA were assessed for resistance to clubroot caused by Plasmodiophora brassicaeWoron. Two French isolates of the pathogen (K and SJ) were used in the experiments under controlled conditions. The reaction of the 126 cauliflower accessions to naturally occurring clubroot was also evaluated in field trials. Kales exhibited considerable variation for expression of disease resistance and high levels of resistance were found in several accessions. In this group, single resistant plants were observed in most of the morphological types and from quite different geographical origins. Cabbage accessions were moderately to highly susceptible to both isolates. All cauliflower populations proved to be highly susceptible to K isolate and moderately susceptible to SJ isolate. In field trials, cauliflowers were also severely infected. Two lines selected from a resistant kale population were highly resistant against a large range of pathotypes of the pathogen. These lines presented a sufficient level of resistance to be directly useful in the breeding program in order to develop cauliflower and broccoli hybrids resistant to clubroot. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

9.
N. Inomata 《Plant Breeding》2002,121(2):174-176
In this cytogenetic study the progeny of all crosses were investigated in F1, F2 and backcross (BC1) hybrids. Brassica napus and F1 hybrids between B. napus and B. oleracea, and between B. napus and three wild relatives of B. oleracea (B. bourgeaui, B. cretica and B. montana). Each of the wild relatives has 18 somatic chromosomes. Interspecific F1 hybrids were obtained through ovary culture mean. These had 28 and 37 chromosomes and their mean pollen fertility was 10.7% and 93.0%, respectively. Many F2 and BC1 seeds were harvested from the F1 hybrids with 37 chromosomes after self‐pollination and open pollination of the F1 hybrids, and backcrossing with B. napus. Many aneuploids were obtained in the F2 and BC1 plants. It is evident from these investigations that the F1 hybrids may serve as bridge plants to improve B. napus and other Brassica crops.  相似文献   

10.
Clubroot disease caused by Plasmodiophora brassicae is one of the major diseases of Brassica crops, often devastating to the cultivation of cruciferous crops in temperate regions. In a previous study (Moriguchi et al. 1999) identified three major quantitative trait loci (QTLs) for clubroot resistance, each in a separate linkage group, in a population derived from a cross between a clubroot‐susceptible inbred cabbage line, Y2A and a resistant inbred kale line, K269. In this study, the original random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers were converted into sequence‐characterized amplified region (SCAR) markers to facilitate large‐scale marker‐assisted screening of clubroot resistance in cabbage breeding. Of 15 RAPD markers closely linked to the three QTLs, nine SCARs were developed as dominant markers after cloning and sequencing. In addition, two RAPD markers were converted into co‐dominant cleaved amplified polymorphic sequence (CAPS) markers, and one RFLP marker out of three tested was converted to a dominant SCAR marker. The effect of selection for resistance by the improved markers was evaluated in progeny plants in the F2 and F3. A total of 138 F2 plants were genotyped with nine SCARs and 121 well‐distributed makers consisting of 98 RAPD, 19 RFLP, two isozymes, and two morphological markers in order to estimate the level of resistance and the proportion of undesirable alleles from the kale in non‐target areas in each of the F2 populations. An F2 plant, YK118, had kale alleles at QTL1, QTL3 and QTL9. Three F2 plants, namely, YK107, YK25 and YK51 had kale alleles at only QTL1, QTL3 and QTL9, respectively. These F2 plants were selected for their low proportion of alleles derived from kale in non‐target regions. YK118, like the resistant kale parent, expressed very high resistance to three field isolates of Plasmodiophora brassicae, whereas the mean disease index in the F2 and F3 plants carrying only single QTLs was intermediate. The QTLs showed no differential response to the isolates. These plants with improved resistance will be useful as parental inbred lines for F1 hybrids.  相似文献   

11.
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   

12.
Colchicine-induced autotetraploids produced in the medicinally important solanaceous plant Hyoscyamus albus (2n = 68) revealed a general increase in pollen, stomata and seed size, but resulted in the reduction of leaf size and plant height. Also, an initial performance trial showed a decline in biomass yield but an increase in alkaloid content of 16.2 %. Thus, in terms of alkaloid yield, the tetraploids demonstrated a slight improvement over diploids for this economic product. Seed fertility of the raw colchiploids was low but a higher value (> 80 %) could be obtained in advanced generations following rigid selection. High fertility was accompanied by a diploidized meiotic chromosome behaviour in the autotetraploids, with high bivalent pairing and regular anaphase separation. Bivalents were predominantly of open type in the autotetraploids as against a predominance of ring bivalents with distal chiasma localization in the parental diploids. The algebraic estimate of multivalent pairing frequency recorded even in the raw colchiploids was quite low (0.239) compared to that expected on the basis of random pairing (0.667), which further dropped to 0.107 in the C3 generation. Such reduction in multivalent frequency in autotetraploids could be brought about by a combination of reduction in crossover frequency and correction in pachytene pairing.  相似文献   

13.
14.
A male sterile plant, 79-399-3, was identified from a spring cabbage line 79-399 in 1979. Light-microscopic studies with paraffin section indicated that meiotic division stopped at the tetrad stage. The ratio of male sterile plants to fertile plants in the progenies of test crosses was 1:1 in five experiments conducted in 1982 and 1991–1994. However, some male sterile plants were sensitive and developed a very low number of viable pollen grains. When sensitive male sterile plants were selfed, the progenies segregated into male sterile and fertile plants at a ratio of 3:1. The male sterile plants from selfing of sensitive male sterile plants were propagated by tissue culture and crossed with different inbred lines. From the progenies of the crosses, populations with 100% male sterile plants were observed. The results indicated that homozygous dominant male sterile (MsMs) plants segregated from the selfed progenies. Populations with 100% male sterile plants and stable male sterility were developed as male sterile lines. Several favorable combinations were also selected by crossing the male sterile lines with inbred lines with high combining ability for desirable horticultural characters. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
A restriction fragment length polymorphism (RFLP) – based linkage map of Chinese cabbage (Brassica rapa ssp. pekinensis) (2n=20) including two agronomic traits, clubroot resistance and orange-yellow pigmentation, was constructed using doubled haploid parents. The total linkage distance was 735 cM; 63 loci were distributed into ten linkage groups. Clubroot resistance of the parental line T136-8 to the current pathotype, race 2, was predominantly controlled by a single dominant gene that originated from European turnip. The locus for clubroot resistance by the dominant major gene (CRa) was mapped on linkage group 3, and RFLP loci HC352b and HC181 were located 3 cM and 12 cM from it, respectively. The locus HC352b was identified by a 4.4 Kb Eco R I fragment, which segregated for null allele. The absence of an allelic fragment in HC352b could be interpreted by deletion in the resistance source; homozygotes for CRa could be efficiently selected by detecting null types for the marker. Orange-yellow pigmentation expressed in head inner leaves and petals was governed by a single recessive gene. The locus (Oy) for the pigmentation was mapped on linkage group 1, being located 17–19 cM from three RFLP loci that were closely linked to each other. The linkage analysis for clubroot resistance and unique pigmentation revealed some informative RFLP markers. Identification of molecular markers for clubroot resistance and other agronomically important traits would provide useful information in breeding programs of Chinese cabbage. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

16.
17.
Summary Selection for resistance to Plasmodiophora brassicae Wor. in oriental groups of Brassica rapa L.Two hundred and sixty-five cultivars of leafy, oriental bassicas were tested for resistance to 18 collections of Plasmodiophora brassicae, the causal agent of clubroot. The tests were conducted in the greenhouse at low and high level inoculum concentrations. Eleven cultivars of B. rapa pe-tsai, five cultivars of B. rapa pak-choy and three cultivars of B. rapa choy-sum consistently segregated for resistance at the lower concentration of inoculum (1000 spores/ml). All 265 cultivars were susceptible at the higher concentration (1 000 000 spores/ml). Three cultivars were used in pedigree and recurrent selection schemes for increased resistance. After three cycles of selfing resistant individuals, significantly more resistant S3 lines were derived from each cultivar. Lines derived from two cultivars. Chinese White and PI 257236, continued to improve with each cycle of selection and demonstrated increased resistance to higher levels of inoculum (up to 1 000 000 spores/ml) New cultivars based on intercrosses of S2 resistant individuals also had significantly better resistance than the original cultivar. After two cycles of selection in the third cultivar, PI 419007, resistance did not increase and its S2 mass did not differ significantly from the original cultivar. Evidence that indicates resistance is pathotype-non-differential and offers an alternative to major gene, pathotype-differential types of resistance currently being introduced to the leafy oriental brassicas from other Brassica rapa groups.  相似文献   

18.
Clubroot resistance (CR) is an important trait in Chinese cabbage breeding worldwide. Although Crr1a, the gene responsible for clubroot-resistance, has been cloned and shown to encode the NLR protein, its allelic variation and molecular function remain unknown. Here, we investigated the sequence variation and function of three Crr1a alleles cloned from six CR F1 cultivars of Chinese cabbage. Gain-of-function analysis revealed that Crr1aKinami90_a isolated from the cv. ‘Kinami 90’ conferred clubroot resistance as observed for Crr1aG004. Because two susceptible alleles commonly lacked 172 amino acids in the C-terminal region, we investigated clubroot resistance in transgenic Arabidopsis harboring the chimeric Crr1a, in which 172 amino acids of the functional alleles were fused to the susceptible alleles. The fusion of the C-terminal region to the susceptible alleles restored resistance, indicating that their susceptibility was caused by the lack of the C-terminus. We developed DNA markers to detect the two functional Crr1a alleles, and demonstrated that the functional Crr1a alleles were frequently found in European fodder turnips, whereas they were rarely introduced into Japanese CR cultivars of Chinese cabbage. These results would contribute to CR breeding via marker-assisted selection and help our understanding of the molecular mechanisms underlying clubroot resistance.  相似文献   

19.
Summary Meiosis in 14 interspecific F1 hybrids with three chromosomal levels (triploid, tetraploid, hexaploid; 2n=28, 37 and 55) between Brassica napus L. and 2x and 4x cabbage (B. oleracea var. capitata L.) was studied. The oleracea genome from B. napus maintained close homology with the c genome of cabbage while the campestris genome of B. napus showed partial homology with the c genome contained in the hybrids. Genotypic influence on chromosome pairing was indicated. Structural chromosome differences and spontaneous chromosome breakage and reunion were suggested as causes for the abnormalities which related to the unbalance of the genotypes. The divergence of the genomes of B. napus and B. oleracea and the need for the qualification of the term secondary association were discussed.Contribution No. J. 673, Research Station, Agriculture Canada, St. Jean, Québec.  相似文献   

20.
W. Rygulla    W. Friedt    F. Seyis    W. Lühs    C. Eynck    A. von Tiedemann    R. J. Snowdon 《Plant Breeding》2007,126(6):596-602
Resynthesized (RS) forms of rapeseed (Brassica napus L.; genome AACC, 2n = 38) generated from interspecific hybridization between suitable genotypes of its diploid progenitors Brassica rapa L. (syn. campestris; genome AA, 2n = 20) and Brassica oleracea L. (CC, 2n = 18) represent a potentially useful resource to introduce resistance against the fungal pathogen Verticillium longisporum into the gene pool of oilseed rape. Numerous cabbage (B. oleracea) accessions are known with resistance to V. longisporum; however, B. oleracea generally has high levels of erucic acid and glucosinolates in the seed, which reduces the suitability of resulting RS rapeseed lines for oilseed rape breeding. In this study resistance against V. longisporum was identified in the cabbage accession Kashirka 202 (B. oleracea convar. capitata), a zero erucic acid mutant, and RS rapeseed lines were generated by crossing the resistant genotype with two spring turnip rape accessions (B. rapa ssp. olerifera) with zero erucic acid. One of the resulting zero erucic acid RS rapeseed lines was found to have a high level of resistance to V. longisporum compared with both parental accessions and with B. napus controls. A number of other zero erucic acid RS lines showed resistance levels comparable to the parental accessions. In the most resistant RS lines the resistance and zero erucic acid traits were combined with variable seed glucosinolate contents. Erucic acid‐free RS rapeseed with moderate seed glucosinolate content represents an ideal basic material for introgression of quantitative V. longisporum resistance derived from B. oleracea and B. rapa into elite oilseed rape breeding lines.  相似文献   

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