摘要:

AbstractTissue culture regeneration of plants fromBrassicaspecies can be achieved from various explant types. Their performance, however, varies with the genotype and age of the explant and is sensitive to medium supplements andAgrobacteriumcocultivation. MostBrassicatransformations were carried out usingAgrobacteriumand it was established that nopaline and agropine strains ofA. tumefaciensandA. rhizogenes, respectively, are the most efficient. Application of virulence gene induction is ambiguous. Binary vectors are mostly applied in spite of indications that cointegrate vectors are more efficient. Cotransformation is successful with two different bacteria or with one bacterium carrying both plasmids, however, it has proved problematic to integrate the two transgenes into separate loci. Transformations with wild typerolgenes develop hairy roots, from which transgenic plants can be regenerated. Vectorless transformation is feasible with microprojectile bombardment of microspore derived embryos being the most promising.Antibiotic markers providing resistance to kanamycin, hygromycin, and spectinomycin are applicable as selectable markers, while chloramphenicol is not suitable. Among herbicides, phosphinotricin gives good results while chlorsulfuron is unsuitable forin vitroselection. Major therapeutic antibiotics being successfully applied are carbenicillin, cefotaxime, amoxycillin, and ticarcillin. Standard methods for evaluating transgenic plants also have been applied toBrassicaspecies. Some breeding objectives obtained through genetic transformation are presented.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00907.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn essential quality improvement of rapeseed oil can be obtained by reduction of its linolenic acid (C18:3) content from about 10% to less than 3% of the total fatty acids. Genotypes low in C18:3 have been developed by mutagenesis. The initial summer rapeseed mutant had been low yielding and highly susceptible to various diseases. It has been debated whether the low C18:3 character can be successfully combined with high seed yield for physiological reasons. Therefore, the low linolenic character of mutant M48 was transferred into high‐yielding genotypes by repeated backcrossing to well‐adapted low erucic acid, low glucosinolate (00‐) winter rapeseed cultivars. Lines with low C18:3 content were selected from BC3 and BC4 generations and examined in 1990–95. Positive selection response for seed yield was shown to continue over the years. Presently, the best lines are yielding as well as the control cultivars being equivalent also in oil and glucosinolate contents.In order to test the effect of a low C18:3 content on seed yield, plants with low and with high C18:3 content, respectively, were selected from 16 segregating BC5‐F2populations and bulked to form 32 F3populations. These ‘isogenic’ bulk populations were tested for field performance at four locations in 1995. The results show that C18:3 content of the seed oil is not associated with seed yield, oil content, beginning of flowering, plant height and disease resistance. Means of relative seed yield for the high and the low linolenic F3bulk populations were not significantly different with 88.0% and 86.9% of the control cultivars, respectively. There was a significant interaction between genotypes with high or low C18:3 content and location. This shows that under specific environmental conditions a low C18:3 content may be either favourable or unfavourable. The results indicate that the low C18:3 character of the original mutants per se does not cause a decrease in seed yield, oil content or general fiel

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00908.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe AFLP (amplified fragment length polymorphism) technique has been applied in establishing an extended linkage map of sugar beet. A total of 120 AFLPs were integrated into an existing linkage map based on RFLP markers. Four primer combinations yielded between 19 and 40 polymorphic bands in an F2population consisting of 94 plants. The AFLP loci were evenly distributed over the nine linkage groups, with the exception of linkage group V where the number of AFLPs was significantly low. The AFLPs were found to be reproducible even against the background of different combinations ofTaqDNA polymerases and buffers. However, the quantity of higher molecular weight fragments (>400 bp) was reduced when using plant DNA of poor quality as a template. The results of these experiments are discussed, together with possible applications of AFLPs in sugar beet breeding.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00909.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper reports on the first results of feeding value experiments, assessed with sheep, of hybrids between tetraploid Italian ryegrass (Lolium multiflorum, 2n = 4×= 28) and a progenitor of tall fescue,Festuca arundinaceavar.glaucescens(2n = 4×= 28). Three hybrid populations resulting from either high, low or no selection for palatability were compared with a variety of Italian ryegrass as control and two varieties of the cultivated hexaploid (2n = 6×= 42) tall fescue, one of which had been selected for high palatability. On average, the hybrid populations were found to be as palatable as the improved tall fescue with voluntary intake (VI),in vivodigestibility of organic matter (DOM), and net energy expressed in fodder units for milk, similar to the best palatable tall fescue and to Italian ryegrass. However, selection for improved palatability among hybrids did not result in any further improvement of other traits, except VI in the hybrid selected for high palatability which significantly exceeded VI of Italian ryegrass. In conclusion, intergeneric hybridization betweenL. multiflorumandF. arundinaceavar.glaucescensled to an immediate increase of feeding value compared with selection for palatability in tall fescue. However, to improve feeding value of hybrids further, similar selection for high palatability appeared questionable and possibly detrimental for other agronomic traits because of complicated inheritance in tetraploidL. multiflorum×F. glaucescenshybr

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00910.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractBreeding for salt tolerance in tomato has been impeded by insufficient knowledge of the genetic control of tolerance. The genetic basis of salt tolerance during vegetative growth was investigated by growing a salt‐tolerant (PI174263) and a salt‐sensitive tomato cultivar (UCT5) and their F1, F2and backcross progeny in saline solutions with electrical conductivity of 0.5 (control) and 20 dS/m (salt‐stress). The relative salt‐tolerance of each generation was determined as the percentage of growth (i.e. dry matter production) under salt‐stress relative to growth under control conditions. In all generations, shoot growth was significantly reduced by salt stress. The reduction was largest in UCT5 (56.1%) and smallest in the F1(27.4%), followed by PI174263 (32.3%). Analysis of the absolute and relative growth under salt‐stress indicated that genes contributing to vigour might be different from genes conferring tolerance. Generation means analyses of the absolute and relative growth indicated that the majority of the genetic variation among generations were due to simple (additive and dominance) genetic effects; nonallelic interactions, although significant, were far less important. Partitioning of the total genetic variance by weighted least‐square regression analysis and variance component analysis indicated that 88% or more of the variation was due to additive genetic effects. A moderate estimate of narrow sense heritability (0.49 ± 0.09) was obtained for shoot DW under salt‐stress treatment. The results indicate that tomato salt‐tolerance during vegetative growth can be improved by bree

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00911.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractFor the transfer of valuable traits from wild species into the cultivated tomato, excised globular‐stage embryos 13 and 15 days after pollination (DAP) were culturedin vitro.Plants were regenerated from interspecific crosses ofLycopersicon esculentumcv. ‘Early pink’×L. peruvianumPI270435, and backcrosses ofL. esculentum‘Giban (JF) No. 1’× (‘Early pink’× PI270435). Somatic embryos and single cotyledons emerged on hypocotyl sections of the embryos. Five to nine plantlets per embryo were obtained by clonal propagation. The hybrid nature of the plants is confirmed by comparing hybrids and parents in their ability to regenerate shoots from leaf segmentsin vitro, by comparing plant morphology and characteristics and by chromosome number. This study describes an efficient ‘embryo rescue’ method, as well as somatic embryogenesis by clonal propagation. A novel and simple method for the characterization of the interspecific hybr

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00912.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractHexaploid sunflower species provide potential sources of desirable genes in breeding for resistance to pathogens as well as high protein and oleic acid content. The possibility of using them in sunflower breeding was studied by testing the crossability of hexaploid species to cultivated sunflower, by the analysis of meiosis and pollen viability in the F1interspecific hybrids.The hybrids were obtained from 16 combinations, with 1–18 F1plants per combination. The F1hybrids in general exhibited the dominant phenotype of the wild species. Sterility ranged from 0 to 87.5% per F1combination, while pollen viability ranged from 43.0 to 70.2%.Meiosis was almost normal in the species analysed but irregular in the F1hybrids. Most of the meiocytes showed predominantly bivalents (86.79–90.22%), but univalents (0.00–4.99%) and the multivalents (8.23–10.09%) occurred as well. At anaphase I, chromosome bridges were detected in 6.88–8.48% of meiocytes. Fast chromosomes in meta‐phase I and lagging chromosomes in anaphase I and telophase II were observed in man

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00913.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractResistance toMycosphaerella graminicolacausal agent ofSeptoria triticiblotch, was identified in progenies of crosses with European winter wheat cultivars, Tadorna and Cleo. This resistance was used to develop the resistant spring wheat cultivar Tadinia, selected from ‘Tadorna’/‘Inia 66’ released in 1985. Evaluation of the progeny of intercrosses between ‘Tadorna’, ‘Cleo’, ‘Tadinia’, and two short‐statured resistant lines derived from hybrids with ‘Tadinia’ as one parent indicate the resistance was inherited as a single gene showing partial to strong dominance. The gene in ‘Tadinia’ was designatedStb4.Crosses between another resistant cultivar, ‘Bulgaria 88’, and ‘Tadinia’ suggest that ‘Bulgaria 88’ does not haveStb4.Successful introgression ofStb4intoRht1+Rht2short‐statured lines revealed that plant stature and resistance toM. graminicolasegregated independently. The Stb4 gene has been effective since 1975 againstM. graminicolaextant in California. A high positive correlation between seedling and adult plant disease scores, based on scoring of lesions producing pycnidia, indicated that theStb4gene is expressed throughout the life cycle under both field and greenhouse conditions, confirming that disease screening can be carried out on seedling plants. Separate assessment of necrotic lesions with and without pycnidia indicated that leaf necrosis without pycnidia, observed, especially under greenhouse conditions, can confound disease evaluations and

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00914.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractExcised leaves of four rice varieties, ‘Facagro 57’, ‘Facagro 76’, ‘Kirundo 3’, ‘Kirundo 9’, were chilled for six days at 10/5°C day/night, along with 11 somaclonal families arising from three of these varieties, which had been selected over four generations for improved chilling tolerance. At the end of the chilling treatment, electrolyte leakage from leaf pieces was followed for 12 h and compared with an unchilled control. With unchilled leaves, no varietal differences nor a rise in leakage over time were observed. Chilling induced higher leakages in all varieties, except in ‘Kirundo 3’ at the time of first measurement, and a continuous rise over time was found in all varieties. Varietal differences were detected, ‘Kirundo 3’ being the least affected, followed by ‘Kirundo 9’ and ‘Facagro 76’, and finally ‘Facagro 57’, which coincides with their ranking for chilling tolerance established through chilling survival tests. The leakages were generally lower in the somaclonal families than in the variety they originated from in ‘Kirundo 9’ and ‘Facagro 76’, while the opposite was observed in ‘Kirundo 3’. The significance and usefulness of electrolyte leakage measurement for chilling tolerance screening, and the potentials of somaclonal variation

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00915.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractMarker‐based selection ofEp‐D1bhas been used successfully to incorporate Pch1, the gene for eyespot resistance on chromosome 7D, into commercial wheat. However, attempts to transfer resistance conferred byPch1(on chromosome 7A) through selection forEp‐A1bhave not always been successful. Linkage relations among eyespot resistance genePch2, a gene encoding for an isozyme of endopeptidase,Ep‐A1b, and RFLP markerXpsr121on chromosome 7A were determined using 80 homozygous recombinant substitution lines. The recombinant lines were derived from eyespot susceptible ‘Chinese Spring’ hybridized with a resistant disomic substitution line of ‘Cappelle Desprez’ that has chromosome 7A substituted into ‘Chinese Spring’. Segregations ofPch2, Ep‐A1bandXpsr121fit an expected 1:1 single‐locus ratios based on χ2tests. Linkage analysis revealed thatPch2was not tightly linked toEp‐Alb(15% recombination). However, close linkage (3.8% recombination) existed betweenEp‐A1bandXpsr121. The order of these loci isPch2‐Xpsr121‐Ep‐A1b.UnlikePch1andEp‐D1b, where little or no recombination is found,Pch1andEp‐A1bshowed considerable recombination and therefore linkage cannot be utilized

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1996.tb00916.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY