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1.
Elizabeth Keep 《Euphytica》1985,34(2):509-519
Summary In black currant (Ribes nigrum) backcross progenies segregating for resistance to the gall mite, Cecidophyopsis ribis
Westw. (gene Ce from Ribes grossularia L.), and to American gooseberry mildew, Sphaerotheca mors-uvae (Schw.) Berk. (gene Sph
3from R. glutinosum), significant differences in season of leafing out occurred between the resistant and susceptible classes. The data are consistent with the hypothesis that two additive genes, Lf
1and Lf
2, controlled season of leafing out and that Ce and Sph
3 were linked with Lf
1. 相似文献
2.
E. Keep 《Euphytica》1986,35(3):843-855
Summary Cytoplasmic male sterility (cms) is described in the F1 hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf
1) and recessive for the other (Rf
2).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph
3(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf
1(one of two dominant additive genes controlling early season leafing out) indicated that Rf
1and Rf
2were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf
1, and 0.15 for Lf
1-Sph
3were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph
3.It is suggested that competitive disadvantage of lf
1-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph
3. Poor performance of lf
1- (and possibly lf
2-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off). 相似文献
3.
Summary The electrophoretic isozyme phenotypes for the AAT-2 and AAT-3 regions of leaves of Triticum turgidum, T. aestivum, Secale cereale, x Triticosecale (hexaploid) and T. aestivum/ S. cereale 6R addition line are described. The phenotypes varied in distribution and relative intensity of the isozyme bands, which were densitometrically measured. The results are consistent with a hypothesis of the dimeric structure for the AAT-2 and AAT-3 systems. 相似文献
4.
It has been hypothesised that wheat yields may be increased by lengthening the duration of the stemelongation phase. This
paper reports studies on the effects of chromosomes carrying major photoperiod genes (Ppd-A1, Ppd-B1, Ppd-D1) in different genetic backgrounds, on responses to photoperiod before and after jointing, when the onset of stem elongation
occurs, and on number of grains per spike. A field experiment considered the effects of two photoperiods on Chinese Spring
and 12 substitution lines, in which chromosomes 2A, 2B or 2D had been substituted by those from four contrasting cultivars.
The phase from seedling emergence to jointing (EM-JO) was more responsive than that from jointing to anthesis (JO-ANT), but
no relationship was found between the duration of these phases. EM-JO length affected leaf and spikelet number and consequently
grains per spike, but this component was further influenced by JO-ANT duration. Our results confirmed that the phases are
independent in sensitivity, supporting the hypothesis that genetic manipulation of phase duration could enhance yield, but
no evidence was found of any particular Ppd allele being responsible for major responses to photoperiod during stem elongation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Summary Monosomic analysis of resistance to stem rust, race 11 (isolate G 425) was carried out in the cultivar Almus (GDR) possessing a 1B/1R translocation. F2 progenies of monosomic and disomic F1 plants of Almus crossed with 21 monosomic lines of Chinese Spring were tested. Two lines (1B and 6B) differed significantly from the disomic segregation ratio by a higher number of resistant plants and two other lines (1D and 6A) by a lower number of resistant plants. The results fitted a hypothesis comprising the interaction of two genes for resistance and two inhibitors. 相似文献
6.
A phenotypic diversity index (PDI) was calculated using 10 agronomiccharacteristics recorded in 90 accessions of 2-row spring barleys and 29accessions of 6-row spring barleys grown in the Nordic Region. The PDIranged from 0.0308 to 0.6245 in 2-row barley accessions and from0.0314 to 0.7016 in 6-row barley accessions. The average PDIs were0.2178 and 0.2438 in 2-row and 6-row barley germplasm, which confirmsthat some older cultivars were parents of newer cultivars. The lowest PDIwas between accessions with the same name, which suggest that irrespectiveof their market source, they were the same cultivars. The largest PDI rangesin 2-row barley cultivars within the same country or release decade werecorrelated to the number of accessions in the respective cluster, whichsuggests that phenotypic diversity in this germplasm depends on the numberof cultivars included in the cluster. However, this association was not alwaysobserved in 6-row barley cultivars. The most distinct 2-row cultivars wereArla and Akka from Sweden, whereas Sigur and Tampa from Iceland werethe most distinct 6-row cultivars as determined by both PDI and averagelinkage cluster analysis. This analysis also confirm that the 2-row barleyaccessions Jenny, Triumph, and Vega, which were obtained from twodistinct market sources, and the 6-row barley accessions under the nameAgneta (but from three market sources) were the same. The analysis ofvariance of the PDI indicates that 6-row germplasm may be clusteredaccording to their geographical origin or decade of release, but this was notobserved in 2-row barley germplasm. This research demonstrates theadvantage of PDI to assess variation among breeding pools. 相似文献
7.
Inheritance of yield components and yield in relation to evidence for heterosis in F1 barley hybrids
Summary Yield components and yield were studied in F1 barley hybrids produced by hand pollination or male sterility. Grain number exhibited only partial dominance but grain weight showed dominance or overdominance and contributed to the heterotic situation particularly in 2×6-row crosses. For the commercial exploitation of heterosis it is essential that hybrids should be found which show greater dominance for high grain number. 相似文献
8.
Summary A method of analyzing host genotype x rhizobial strain interaction for N2 fixation potential, based on the principle of structural relationship analysis, is proposed. When this interaction is significant, selecting genotypes for high N2 fixation potential is incorrect, because the N2 fixation efficiency is dependent on the rhizobial strain used. Under such circumstances, grouping genotypes based on average fixing ability (AFA), a linear response to the effectiveness of rhizobial strain, and specific fixing ability (SFA), deviation from the linear response in terms of the magnitude of the error variance, is useful before initiating a breeding program for enhanced N2 fixation. Host genotype x strain interaction effect is partitioned into two components, and two parameters are derived which estimate AFA and SFA. N2 fixation data from 3 mungbean genotypes and 6 rhizobial strains are used to illustrate this method. 相似文献
9.
O. S. Bindra 《Euphytica》1985,34(3):849-856
Summary Growing of irrigated cotton in the Sudan, in relation to pest control, entered the crisis phase around 1967–68 and the disaster phase in 1980–81. At the cruxes of the pest-control problem lay the uncontrollable whitefly-induced lint stickiness and the American bollworm (ABW). The paper gives the succession of cotton varieties in the Gezira and reviews the reports on higher incidence of the whitefly and ABW on newer varieties.Logical explanations offered for the higher pest incidence on newer varieties lead to the conclusion that as compared with Sakel-type cottons, the Lambert-type cottons would have a greater build-up of the whitefly, while Acala cottons would have not only larger populations of both whitefly and ABW but also increased losses from the latter. Changes in area under different types of cotton are shown graphically in relation to the pest-control situation and a case is made for the hypothesis that varietal changes in the Gezira had profound ecological effects which favoured the whitefly and ABW, but made sprays less effective, leading eventually to the cotton-pest-control predicament. Finally, based on recent experience, a hope is expressed that switching to cultivars less favourable to the pests and more suited for efficient pesticide application would ease the cotton-protection problem. 相似文献
10.
D. J. Ockendon 《Euphytica》1982,31(2):325-331
Summary A total of 31 S-alleles was found in a survey of 197 cabbage plants representing 11 cultivars of diverse type. Most of these S-alleles also occurred in either kale or Brussels sprouts, but five of them have not been found previously and apparently occur only in cabbage. A more detailed study of five cultivars of spring cabbage showed only 12 S-alleles in all, with 6–10 S-alleles in four older cultivars and only 3 S-alleles in the newer more highly selected cultivar. S2 was by far the commonest S-allele, as it is in B. oleracea as a whole. The highly recessive alleles S5 and S15 were not particularly common in cabbage and this may partly explain why the sib problem in F1 hybrids is apparently less in cabbage than in Brussels sprouts. Three cases were found in which an S-allele was completely recessive in both the stigma and the pollen. The problems for the breeder created by this rather unusual situation are discussed. 相似文献
11.
Summary Callus induction and green plant regeneration at high frequencies from an interspefic hybrid, Oryza sativa L. x O. rufipogon Griff. has been achieved by simply coordinating the growth regulators in the induction medium. The study was conducted with two different basal media (Potato-2 and N6) and seven different combinations of growth regulators 2,4-D, NAA and kinetin. Synergistic effects of the two auxins in enhanced anther response to callus induction and subsequent green plant regeneration were observed in both media. The highest frequency of callus induction was obtained on Potato-2 medium supplemented with 1 mg/12,4-D, 2 mg/l NAA and 1 mg/l kinetin. The same combination of growth regulators which yielded higher frequencies of callus induction also induced higher mean number of calli per anther. Although the calli formed on N6 medium showed high regenerability, there was a concomitant increase in the number of albinos among the regenerants. The auxins in the induction media had considerable influence on the regeneration capacity of the calli. The regeneration frequencies were higher from calli formed in the presence of both auxins in the induction media. The levels of growth regulator combinations seem to influence the green plant regeneration especially for calli induced on Potato-2 medium. Among the pollen grain derived plants the majority were either haploids or double haploids and very few were chromosomal variants. 相似文献
12.
Summary
Lycopersicon pimpenellifolium L3707, resistant to the late blight oomycete Phytophthora infestans was crossed with the susceptible Lycopersicon pimpenellifolium 14377 or the susceptible Lycopersicon esculentum ZH. Progeny F1 and F2 generations were scored at the 5-leaf stage for resistance against 175 field and recombinant isolates of the pathogen. F1 plants exhibited various levels of moderate resistance and F2 plants segregated 3:6:7 resistant/moderately resistant/susceptible. The data support the hypothesis that race-non-specific resistance in L3707 is controlled by two independent genes: a partially-dominant gene and a dominant epistatic gene. 相似文献
13.
Richard N. Lester 《Euphytica》1989,44(1-2):125-132
Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected. 相似文献
14.
Tef is a staple cereal of Ethiopia in high demand by consumers. In order to cope up with this high consumer demand, productivity
per unit of land must increase through the development and use of high-yielding varieties. To this effect, the National Tef
Research Project has long been striving towards the development of high yielding varieties through direct selection from germplasm
and concentrating favourable alleles through hybridization and selection, despite the tedious crossing technique. The objective
of this study was to assess the degree of genetic variation in F2 populations of tef as a basis for improving grain yield. F2 populations from 12 crosses and their parents were grown at the Debre Zeit Agricultural Research Center, Ethiopia, and assessment
was made on eight traits on individual plant basis. Eleven of the 12 crosses showed substantial genetic variation for grain
yield and its components, indicating the potential for improvement through selection. Moreover, grain yield, plant weight
and yield related traits showed moderate to high heritability values (17–80%). In all the crosses, tiller number, panicle
weight, yield per panicle and panicle length showed significant (P ≤ 0.05) and positive association with grain yield. Considering the degree of genetic variation and heritability values, emphasis
should be given to selected crosses in an effort to developing high-yielding tef varieties. 相似文献
15.
Summary This article reports the culture and plant regeneration of Tripsacum dactyloides. Mature embryos of Tripsacum dactyloides dactyloides were used to obtain embryogenic callus cultures. Currently, 180 normal plants have been regenerated from these cultures. Callus was initiated on MS medium supplemented with dicamba (10 mol or 20 mol) and sucrose (3% or 6%), and plants were regenerated on hormone free MS medium containing 2% sucrose. No significant differences were found in callus initiation frequency or in embryogenic response of cultures on the four combinations of sucrose and dicamba tested. The embryogenic cultures have been maintained for 9 months (12 subcultures) and have retained regeneration capacity. Plants regenerated from tissue culture of maize-by-Tripsacum hybrids could be useful in maize improvement. 相似文献
16.
J. Smartt 《Euphytica》1980,29(1):121-123
Summary On the basis of phytogeographic evidence it is suggested that Psophocarpus tetragonolobus has an African ancestry, a possible parallel with the origin of guar (Cyamopsis tetragonoloba) is suggested. The most probable ancestral species is Ps. grandiflorus native to East Africa from Ethiopia to Zaire. This hypothesis could be tested by experimental hybridization between the cultigen and its closest wild relative Ps. grandiflorus. 相似文献
17.
Felicitas Svejda 《Euphytica》1979,28(2):309-314
Summary Heritability in the broad sense and the distribution of levels of winterkill were analyzed in the offspring from hardy diploid and from hardy, semi-hardy and tender tetraploid roses. The heritabilities for different parental combinations ranged from 51 to 92%.The offspring from crosses of hardy parents were also hardy and showed little variation in hardiness levels. The offspring from crosses of hardy roses with the semi-hardy R. kordesii and the tender Queen Elizabeth survived the winters without coverage but showed a wider variation in hardiness levels.The desirable level of hardiness, an average winterkill of less than 10%, could be achieved through selection in the first or second generation of breeding, depending on the hardiness levels of the parents. The hypothesis is advanced that winterhardiness in roses is controlled by very few or closely linked genetic factors.Contribution No. 557 相似文献
18.
The F1 hybrids of seven diploid Alstroemeria species (2n=2x=16) were investigated for the production of numerically unreduced (2n) gametes and their mode of origin. Based on a survey of 17 interspecific hybrid combinations,consisting of 119 genotypes,
it was found that the F1 hybrids of Chilean-Brazilian species mostly produced first division restitution (FDR) 2n gametes. These F1 hybrids were self-pollinated in order to obtain F2 seeds, which was an indication that the F1 plants also
produced 2neggs simultaneously. All the F2 progeny plants were typical allotetraploids, most of which formed 16 bivalents and a small
proportion formed multivalents during metaphase I stages of meiosis. Through genomic in situ hybridisation (GISH) it was proved that multivalent formation in F2plants, derived from A. inodora ×A. pelegrina hybrid, was due to homoeologous recombination but not from reciprocal translocations. In order to test the segregation pattern
of the recombinant chromosomes, an F3 population from one genotype, P6C49-6, was investigated. The recombinant chromosomes
assorted independently from each other supporting the hypothesis that the segregation of chromosomes in ring quadrivalents
did not behave like those in translocation heterozygotes. It was concluded that in allopolyploids of Alstroemeria,bilateral sexual polyploidisation could accomplish genetic recombination by both homoeologous crossing-over as well as through
the assortment of chromosomes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Postulation of leaf (brown) rust resistance genes in 70 wheat cultivars grown in the United Kingdom 总被引：1，自引：0，他引：1
Multi-pathotype tests on 70 U.K. wheat cultivars permitted postulation of eight known seedling genes for resistance to Puccinia recondita f. sp.tritici either singly or in combinations. The most commonly detected gene was Lr13 (present in approximately 57% of cultivars), followed by Lr26 (22%), Lr37 (20%), Lr10 (17%), Lr17b (LrH) (10%), Lr1 (7%), Lr3a (6%) and Lr20(4%). This information permitted assessments of adult plant resistance (APR) in some cultivars, in field nurseries inoculated
with pathotypes of P. recondita f. sp. tritici of known pathogenicities for characterized seedling resistance genes. APR was identified in eleven cultivars, including Avalon
and Maris Ranger, which lacked detectable seedling resistance genes. The results provided a better understanding of specific
resistances in the cultivars tested than was available from previous reports.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Characterisation and origin of rust and powdery mildew resistance genes in VPM1 wheat 总被引：3，自引：0，他引：3
Summary The expression of rust resistances conferred by closely linked genes derived from VPM1 varied with environmental conditions and with genetic backgrounds. Under low light and low temperature conditions seedlings carrying Yr17 showed susceptible responses. Stem rust and leaf rust resistance genes Sr38 and Lr37 tended to confer more resistance at 17±2° C than at normal temperatures above > 20° C. These studies supported the hypothesis that Yr17, Lr37 and Sr38 were derived from Aegilops ventricosa, whereas Pm4b was probably derived from T. persicum. Studies on certain addition lines and parental stocks indicated that wheat cytoplasm may enhance the expression of Sr38. 相似文献