摘要:

AbstractThe contribution of improvements in morphophysiological traits to increased gram yield in spring wheat (Triticum aestivumL.) and the achievements of breeding for high bread‐making quality in Finland since the 1930s were assessed. Ten wheat cultivars released in Finland between 1939 and 1990 were evaluated in Held experiments at the Viikki Experimental Farm, University of Helsinki, Finland (60°13′N) in 1991 and 1992. Twenty‐two traits representing maturity, plant architecture, plant stand structure and N accumulation, and nine quality traits, including protein concentration and protein quality, were assessed. A 20 % increase in grain yield arising from cultivar improvement was associated with a 7 % reduction in height, an 80 % improvement in lodging resistance, and a 15 % higher harvest index (HI). Ear weight was 30 % higher in the modern cultivars. The higher ear weight of the modern cultivars was a result of more grains per ear and a higher spikelet weight. No decrease in vegetative phytomass in modern cultivars was recorded in this study. Grain yield and total N accumulation increased simultaneously and a positive correlation between year of cultivar release and nitrogen index was established. Although use of high N fertilizer application rates resulted in significantly improved baking quality of the flour, no trend between baking quality and year of cultivar release was recorded. The relatively low HI recorded in this study suggests that further yield increases art‐likely to be achieved by selecting for h

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00721.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractRht12, a dominant dwarfing gene of wheat, was shown to be located distally on the long arm of chromosome 5A. Lack of recombination with the awn inhibitorB1suggested thatRht12is cither tightly linked to this gene or is, in this material, a pleiotropic expression of the gene. Linkage toβ‐Amy‐A1was also very tight, indicating thatRht12is present on the segment of chromosome SAL ancestrally translocated from 4AL. The close linkage toβ‐Amy‐A1also suggests thatRht12is not a homoeoallele of the commercially important GA‐insensitive dwarfing genes.Analysis of near‐isogenic lines in a number of genetic backgrounds showed thatRht12reduces height without altering ear size and significantly increases spikelet fertility. However its successful utilization in breeding programmes will require careful selection since in some backgrounds the gene reduces grain numbers and grain size. In all backgrounds,Rht12delayed ear emergence time by around 6 days. A delay of this magnitude could, in many environments, adversely affect yield if it is not neutralized by altering the balance of other genes determining ear e

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00722.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractEighteen common‐wheat varieties grown for three seasons at 31 locations in Italy were used to study the relationships between cultivar adaptation patterns, climatic factors and morphophysiological traits of genotypes, as well as defining macro‐environments for the selection and recommendation of genotypes in the region. The variances of both the genotype‐location and genotype–season interactions were significant, the former being almost 80% greater than the latter. Some 10.4% of genotype‐location interaction was accounted for by heterogeneity of genotype regressions on site mean, 38.0% by the first two axes of a principal components analysis and 32.0% by definition of four macro‐environments. Occurrence of genotype‐location interaction was related to the level of late frosts, winter cold, and late drought and heat stress at each location, and to heading date and tolerance of frost,Septoriablotch and lodging in each genotype. Following estimates of broad‐sense heritability, breeding for specific adaptation may be envisaged for northern and central Italy on the one hand, and southern Italy on the other. Morphophysiological traits contributing to better performance in each of these macro‐environmen

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00723.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractGenetic analyses were carried out withB. napuslines that differed in total content of individual glucosinolates (GSLs), as well as in their profile. Inheritance of total GSL content was studied with a complete F1diallel mating of eight doubled haploid (DH) lines (5–120/μmol GSL/g dry seed) as well as with the segregating populations of two crosses between DH lines. Most of the genetic variability was caused by gca effects; heterosis was not important; heritability of GSL content was high (h2b, = 0.95, h2n= 0.87). For GSL contents below 20/μmol/g seed, heritability values reached h2b, = 0.69 and h2n, = 0.66. Low total GSL content was found to be controlled by 4–5 recessive genes with additive gene action. Alkenyl GSL profiles studied in F2from resynthesized rapeseed lines were determined by four loci, two that are responsible for the elongation of the butenyl to pentenyl GSLs and two that are responsible for hydroxylation of alkenyl GSLs. Initial genetic studies of indolyl GSL contents from 0.1–4.5/μmol/g show that two or three genes may be involved. The frequency distribution of F2phenotypes was virtually continuous due to both segregational and environmental variation. Genotypes with low alkenyl and low indolyl GSL contents were selected after crossing parents with low alkenyl/high indolyl and high alkenyl/low indolyl GSL content. The alkenyl GSL profiles are discussed with regard to the parental diploid speciesB. oleraceaandB. ca

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00724.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThree methods of chromosome doubling to produce doubled haploid plants from microspore cultures ofBrassica napuswere compared: colchicine treatment of microspore‐derived plants, microspore‐derived embryos, and isolated microspores. In the whole plant treatment, 53% of the treated plants set seed, but the treatment delayed plant growth and reduced seed set. When microspore‐derived embryos were treated with colchicine, the doubling frequency was 32% (compared to 15% for spontaneous doubling). Direct colchicine treatment of isolated microspores resulted in a doubling efficiency of 70 % of the whole plants. This treatment also stimulated embryogenesis in microspore culture, leading to increased plant regeneration. Thus, direct chromosome doubling of isolated microspores is efficient and more than 10 000 doubled haploid plants have been produced in this manner in the past three years in order to accelerate the plant‐breeding

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00725.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractBy transferring dominant male sterility (DMS), caused by the gene Ms, to genotypes with various types of cytoplasm 12 DMS lines were developed and a number of crosses made between the DMS lines and other genotypes ofBrassica napus.During the course of this population improvement programme, 16 genotypes were identified as having the capacity to restore the fertility of F1plants with theMsgene. According to pedigree analysis, the inhibitory gene in those lines probably originated from a few genotypes from Australia and Germany. In further studies the inheritance of the sterility inhibition was determined, providing definite evidence that dominant male sterility and its inhibition inB. napusare controlled by two dominant interacting genes rather than by multiple alleles.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00726.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractTwo different protocols forin vitroregeneration of cassava using zygotic embryos and nodal axillary meristems have been developed. In both cases, buds were regenerated directly from excised explants without an intervening callus phase after a two‐step culture procedure. In cotyledonary explants derived from zygotic embryos, prolific shoot formation occurred within 2—3 weeks on MS medium supplemented with 0.5—5 mg/1 BAP alone or in combination with 0.1 mg/1 NAA. Nodal explants with axillary meristems derived from aseptically grown seedlings or stem cuttings were used to initiate a round compact bulb‐like structure on MS medium containing 10 mg/1 BAP. These latter structures, when cultured on MS medium supplemented with 0.1 mg/1 NAA, 1 mg/1 BAP and 0.1 mg/1 GA3, produced multiple shoots. Somatic embryos isolated at the globular/torpedo stage from zygotic embryo explants were also capable of multiple shoot production on medium with 1 mg/1 BAP. Rooting of regenerated shoots exceeded 95 % in phytohormone‐free MS medium. No change in their ploidy levels was observed. Therefore, the protocols developed should be of use in the particle gun andAgrobacterium‐mediated genetic transformation

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00727.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractInadequate stand establishment can be a major constraint to high grain and fodder yields of pearl millet (Pennisetum glaucum[L.] R. Br.) in the semi‐arid tropics. In this study, two laboratory screening procedures designed to improve components of stand establishment were evaluated. In the first procedure the ability of seedlings to emerge from the soil at 45 °C was tested and in the second procedure the ability of seeds to germinate at 45°C was measured. Two cycles of recurrent selection were conducted with each procedure in the Higrop and Senpop pearl millet gene pools. The resultant populations were evaluated to measure the efficacy of the screening procedures. Selection for increased emergence was effective in the Cc of Higrop. When emergence percentage was averaged across Higrop and Senpop, recurrent selection increased emergence percentage by 7.4 % per cycle. In future, the size of the emergence screening units and number of seeds screened per progeny tested should be increased. The germination selection procedure was ineffect

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00728.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractAmong the available sources of cytoplasmic male sterility only the A1source has so far been exploited for breeding commercial hybrids of pearl millet (Pennisetum glaucum(L.) R. Br.). The influence of this source was studied by comparing the combining ability of five pairs of lines that differ in their cytoplasmic source. The effect on the expression of the traits, though modified by environment, was significant. The manifestation of cytoplasmic effects on general combining ability (GCA) was different for various traits. In general, the A1cytoplasm showed a positive influence on GCA estimates for plant height, grain yield, and a negative influence on days to flowering. The variable magnitude of cytoplasmic effects on the GCA of lines indicated that such effects were the result of interaction between cytoplasm and nuclear genes.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00729.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractFour morphologically different clones ofMiscanthus sinensis‘Giganteus’, presently grown in Austria, one ornamental,M. sinensis, and two cultivars ofM. sacchariflorus, were studied to determine their chromosome number, chromosome morphology and meiotic behaviour. The clones ofM. sinensis‘Giganteus’ uniformly showed a somatic chromosome number of 57. The ornamentalM. sinensis, and oneM. saccharifloruscultivar had 38 and the secondM. sacchariflorusgenotype had 76 chromosomes. While the ornamentalM. sinensisexhibited a regular meiosis with predominantly ring bivalents,M. sinensis‘Giganteus’ displayed a highly irregular meiosis with stickiness, frequent occurrence of trivalents and a large number of laggards in both the first and second anaphases. The presence of two satellited chromosomes suggests an allotriploid genome constitution; the trivalents indicate the involvement of closely related species in the amphiploid. Triploidy of the plants is supposed to be the major cause of their sterility. Suggestions are made for further cytogenetic studies including genome analysis and an attempt to resynthesizeM. sinensis‘Giganteus’ to provide an insight into the genetic architecture of the plant and to generate new genetic variations for br

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1994.tb00730.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY