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1.
Gliadin polymorphism in wild and cultivated einkorn wheats 总被引:4,自引:0,他引:4
M. Ciaffi L. Dominici D. Lafiandra 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):68-74
To study the relationships between different species of the Einkorn group, 408 accessions of Triticum monococcum, T. boeoticum, T. boeoticum ssp. thauodar and T. urartu were analyzed electrophoretically for their protein composition at the Gli-1 and Gli-2 loci. In all the species the range of allelic variation at the loci examined is remarkable. The gliadin patterns of T. monococcum and T. boeoticum were very similar to one another but differed substantially from those of T. urartu. Several accessions of T. boeoticum and T. monococcum were shown to share the same alleles at the Gli-1 and Gli-2 loci, confirming the recent nomenclature that considers these wheats as different subspecies of the same species, T. monococcum. The gliadin composition of T. urartu resembled that of the A genome of polyploid wheats more than did T. boeoticum or T. monococcum, supporting the hypothesis that T. urartu, rather than T. boeoticum, is the donor of the A genome in cultivated wheats. Because of their high degree of polymorphism the gliadin markers may
help in selecting breeding parents from diploid wheat germ plasm collections and can be used both to search for valuable genes
linked to the gliadin-coding loci and to monitor the transfer of alien genes into cultivated polyploid wheats.
Received: 8 July 1996 / Accepted: 12 July 1996 相似文献
2.
Characteristics of genetic variation in the progenies of protoplast-derived plants of rice, Oryza sativa cv Nipponbare 总被引:3,自引:0,他引:3
M. Yamagishi T. Koba T. Shimada K. Itoh Y. Sukekiyo K. Shimamoto 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):1-7
Genetic variation in protoplast-derived rice (Oryza sativa L.) plants was characterized using first and second generation selfed progenies. A total of 133 regenerated plants were obtained
from ten protoplasts of the japonica rice cultivar Nipponbare. Sixty two regenerated plants which set enough seeds for the subsequent field tests at the next
generation and were derived from five protoplasts were selected, and their selfed seeds were used as the first selfed-seed
progeny generation). Fifteen plants were selected from each of the 15 lines, and their selfed seeds were used for tests at the generation. Thirty seven lines (60%) segregated plants with detrimental mutant characters of yellow-green phenotype, dwarf stature, dense and short
panicle, or low seed fertility. According to the segregation patterns in the lines having mutated plants among those originated
from the same protoplasts, the stages of mutation induction were estimated. Additionally, five quantitative traits were changed
in almost all and lines. Varied quantitative traits of heading date, number of spikelets per panicle, and seed fertility, were in a heterozygous
state. However, culm and panicle lengths showed high uniformity, whereas reduced culm and panicle lengths were caused by mutational
changes in polygenes and/or multiple genes.
Received: 20 March 1996 / Accepted: 21 June 1996 相似文献
3.
H. S. Suh Y. I. Sato H. Morishima 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):316-321
Weedy rice (Oryza sativa L.) is an important resource for breeding and for studying the evolution of rice. The present study was carried out to identify
the genetic basis of the weedy rices distributed in various countries of the world. One hundred and fifty two strains of weedy
rice collected from Bangladesh, Brazil, Bhutan, China, India, Japan, Korea, Nepal, Thailand and the USA were tested for variations
in six morpho-physiological characteristics and in 14 isozyme loci. Twenty six weedy strains selected from the above materials
were assayed for the Est-10 locus, six RAPD loci of the nuclear genome, and one chloroplast locus. From the results of multivariate analysis based on
the morpho-physiological characteristics and the isozymes, weedy rice strains were classified into indica and japonica types, and each type was further divided into forms resembling cultivated and wild rice. Thus, four groups designated as
I, II, III and IV were identified. Weedy strains of group I (indica-type similar to cultivars) were distributed mostly in temperate countries, group II (indica-type similar to wild rice) in tropical countries, group III (japonica-type similar to cultivars) in Bhutan and Korea, group IV ( japonica-type similar to wild rice) in China and Korea. In group I, classified as indica, several strains showed japonica-specific RAPD markers, while some others had japonica cytoplasm with indica-specific RAPD markers in a heterozygous state at several loci. One weedy strain belonging to group II showed a wild rice-specific
allele at the Est-10 locus. However, in groups III and IV, no variation was ound either for the markers on Est-10 or for the RAPD loci tested. Judging from this study, weedy rice of group I might have originated at least partly from gene
flow between indica and japonica, whereas that of group II most probably originated from gene flow between wild and cultivated indica rice. Weedy rice of group III is thought to have originated from old rice cultivars which had reverted to a weedy form, and
that of group IV from gene flow between japonica cultivars and wild rice having japonica backgrounds.
Received: 2 May 1996 / Accepted: 30 August 1996 相似文献
4.
Mapping of the Rf-3 nuclear fertility-restoring gene for WA cytoplasmic male sterility in rice using RAPD and RFLP markers 总被引:24,自引:0,他引:24
G. Zhang Y. Lu T. S. Bharaj S. S. Virmani N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):27-33
The cytoplasmic male sterility (CMS) of wild-abortive (WA) cytoplasm has been widely used for breeding hybrid rice. Two restorer
genes for the CMS have been found by traditional genetic analysis. To tag the restorer genes we used a set of near-isogenic
lines (NILs) of Zhenshan 97 carrying different genotypes for fertility restoration from IR24, to perform RAPD analysis. From
the survey of 720 random primers, six RAPD markers were identified to be associated with Rf-3. Three of these OPK05-800, OPU10-1100 and OPW01-350, were mapped on chromosome 1. Two populations from the crosses between Zhenshan 97 A and a near-isogenic restorer line ZSR21 and between Zhenshan 97 A and
IR24 were used for mapping Rf-3. The three RAPD markers and three RFLP markers, RG532, RG140 and RG458, were found to be closely linked to Rf-3 in the two populations. The same location of Rf-3 was also found in a population from the cross of IR58025 A//IR36/IR58025 B. At the RG532 locus, different alleles were found between two CMS
lines, Zhenshan 97 A and IR58025 A, and between two restorer lines, IR24 and IR36. The use of these molecular markers closely
linked to Rf-3 in facilitating the development of hybrid rice is discussed.
Received: 3 January 1996 / Accepted: 17 May 1996 相似文献
5.
Pyramiding transgenes for multiple resistance in rice against bacterial blight,yellow stem borer and sheath blight 总被引:11,自引:0,他引:11
Datta K Baisakh N Thet KM Tu J Datta SK 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(1):1-8
The present investigation revealed that the alk and gel(t) genes, which cause the differences between a japonica rice variety Nipponbare and an indica rice variety Kasalath in terms of the disintegration of endosperm starch granules in alkali solution and their gelatinisation
in a 4 M urea solution, respectively, cosegregated in backcross inbred lines derived from a cross between the two varieties.
The segregation pattern of the profile for amylopectin chain-length, which was distinguished by enrichment in short chains
of DP≦11 and depletion in intermediate-size chains of 12≦DP≦24 in japonica as compared with indica, was exactly the same as those of the above physico-chemical properties of starch granules, and the gene was designated as
acl(t). Gene-mapping analysis showed that the starch synthase IIa (SSIIa) gene is located at the alk locus on chromosome 6 in the rice genome. These results lead us to the possibility that different alleles of the SSIIa gene are responsible for differences in amylopectin structure between the two varieties, in that SSIIa plays a distinct role
in the elongation of short chains within clusters (A+B1 chains) of amylopectin. It is proposed that the activity of SSIIa in japonica rice is reduced in amount or functional capacity relative to the activity of this enzyme in indica rice. This, in turn, would explain why starch from japonica rice has a lower gelatinisation temperature than starch from indica rice and is more susceptible to disintegration in alkali or urea. The evidence for this hypothesis is that the alk(t), gel(t), acl(t) and SSIIa genes all map to the same locus.
Received: 29 January 2001 / Accepted: 12 April 2001 相似文献
6.
P. K. Subudhi S. Nandi C. Casal S. S. Virmani N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):941-949
The cytoplasmic genetic male-sterile (CMS) lines developed at the International Rice Research Institute are valuable in producing
tropical rice hybrids. Efficient use of CMS lines in hybrid rice production will depend on their level of genetic diversity.
Aside from morphological characterization, molecular analysis based on DNA markers can provide information on the genetic
diversity of the germplasm. The Amplified Fragment Length Polymorphism (AFLP) technique was used to fingerprint 71 CMS lines
and four rice cultivars, ‘IR64’, ‘Azucena’, ‘IR74’, and ‘FR13A’. Eleven primer pair combinations specific to the enzymes PstI and MseI were used to generate 530 AFLP markers, 176 of which were polymorphic. Each CMS line revealed a distinct fingerprint. The
AFLP marker-based dendrogram depicted genetic variation among the CMS lines. The CMS lines developed in japonica background
grouped with ‘Azucena’, a japonica cultivar. None of the CMS lines clustered with ‘FR13A’, a flood-tolerant traditional indica
variety. ‘IR64’ was found to be distinct from the other indica CMS lines and clustered with lines developed in its background.
The grouping of CMS lines into a few groups is useful for breeders in selecting genetically diverse CMS lines for hybrid rice
production and in avoiding test crossing every CMS line empirically. This study demonstrated that AFLP is a powerful and reliable
tool in determining the genetic relationships and in producing distinct fingerprints of rice cultivars.
Received: 20 December 1996 / Accepted: 9 October 1997 相似文献
7.
A genome-wide analysis of wide compatibility in rice and the precise location of the S5 locus in the molecular map 总被引:24,自引:0,他引:24
K. D. Liu J. Wang H. B. Li C. G. Xu A. M. Liu X. H. Li Q. Zhang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):809-814
The discovery of wide-compatibility varieties (WCVs) that are able to produce normal fertility hybrids when crossed both
to indica and japonica rice has enabled the fertility barrier between indica and japonica subspecies to be broken and provided
the possibility of developing inter-subspecific hybrids in rice breeding programs. However, a considerable variation in the
fertility level of hybrids from the same WCV crossed to different varieties has often been observed. One hypothesis for this
variable fertility is that additional genes are involved in hybrid fertility besides the wide-compatibility gene (WCG). To
assess such a possibility, we performed a genome-wide analysis by assaying a large population from a three-way cross ‘02428’/‘Nanjing
11’//‘Balilla’ using a total of 171 RFLP probes detecting 191 polymorphic loci distributed throughout the entire rice linkage
map. Our analysis recovered 3 loci conferring significant effects on hybrid fertility. The major locus on chromosome 6 coincided
in chromosomal location with the previously identified S
5
locus, and the 2 minor loci that mapped to chromosomes 2 and 12, respectively, were apparently distinct from all previously
reported hybrid sterility genes. Interaction between the indica and japonica alleles at each of the loci caused a reduction
in hybrid fertility. The joint effect of the 2 minor loci could lead to partial sterility even in the presence of the WCG.
The location of the S
5
locus on the molecular marker linkage map was determined to be approximately 1.0 cM from the RFLP locus R2349. This tight
linkage will be useful for marker-aided transfer of the WCG in hybrid rice breeding and for map-based cloning.
Received: 5 February 1997 / Accepted: 4 April 1997 相似文献
8.
Highly polymorphic microsatellites of rice consist of AT repeats, and a classification of closely related cultivars with these microsatellite loci 总被引:23,自引:3,他引:20
H. Akagi Y. Yokozeki A. Inagaki T. Fujimura 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):61-67
Microsatellites consisting of AT repeats are highly polymorphic in rice genomes and can be used to distinguish between even
closely related japonica cultivars in Japan. Polymorphisms of 20 microsatellite loci were determined using 59 japonica cultivars,
including both domestic and modern Japanese cultivars. Although the polymorphisms of these 20 microsatellite loci indicated
that the Japanese cultivars were genetically quite similar, microsatellites consisting of AT repeats showed high gene diversity
even among such closely related cultivars. Combinations of these hypervariable microsatellites can be employed to classify
individual cultivars, since the microsatellites were stable within each cultivar. An identification system based on these
highly polymorphic microsatellites could be used to maintain the purity of rice seeds by eliminating contamination. A parentage
diagnosis using 17 polymorphic microsatellite loci clearly demonstrated that plants which carried desired chromosome regions
had been selected in breeding programs. Thus, these hypervariable microsatellites consisting of AT repeats should promote
the selection of plants which carry desired chromosomes from genetically similar parents. Backcrossing could also help to
eliminate unnecessary chromosome regions with microsatellite polymorphisms at an early stage in breeding programs.
Received: 8 July 1996 / Accepted: 12 July 1996 相似文献
9.
Comparative mapping of QTLs for agronomic traits of rice across environments by using a doubled-haploid population 总被引:11,自引:0,他引:11
Chaofu Lu Lishuuang Shen Ping He Ying Chen Lihuang Zhu Zhenbo Tan Yunbi Xu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):145-150
We report here the RFLP mapping of quantitative trait loci (QTLs) which affect some important agronomic traits in cultivated
rice. An anther culture-derived doubled-haploid (DH) population was established from a cross between indica and japonica rice
varieties. A molecular linkage map comprising 137 markers was constructed based on this population which covered the rice
genome at intervals of 14.8 cM on average. The linkage map was used to locate QTLs for such important agronomic traits as
heading date, plant height, number of spikelets per panicle, number of grains per panicle, 1 000-grain weight and the percentage
of seed set, by interval mapping. Evidence of genotype-by-environment interaction was found by comparing QTL maps of the same
population grown in three diverse environments. A total of 22 QTLs for six agronomic traits was detected which were significant
in at least one environment, but only seven were significant in all three environments; seven were significant in two environments
and eight could only be detected in a single environment. However, QTLs-by-environment interaction was trait dependent. QTLs
for spikelets and grains per panicle were common across environments while traits like heading date and plant height were
more sensitive to environment.
Received: 22 February 1996 / Accepted: 10 May 1996 相似文献
10.
G. Besnard Y. Griveau M. C. Quillet H. Serieys P. Lambert D. Vares A. Bervillé 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):131-138
A method based upon targetting of intro-gressed markers in a Phomopsis-resistant line (R) of cultivated sunflower, issuing
from a H. argophyllus cross was used to mark the Phomopsis resistance regions. Our study was based upon 203 families derived from a cross between an inbred line susceptible to Phomopsis (S1) and the introgressed resistant line (R).
Families were checked for Phomopsis resistance level in a design with replicated plots and natural infection was re-inforced
by pieces of contaminated stems. Thirty four primers were employed for RAPD analysis. Out of 102 polymorphic fragments between
(S1) and H. argophyllus, seven were still present in (R) suggesting that they marked introgressions of H. argophyllus into (R). The plants were scored for the presence or absence of 19 fragments obtained from five primers, and the relationships between
the presence/absence of fragments in plants and Phomopsis resistance/susceptiblity in the progenies was determined by using an analysis of variance. We found that at least two introgressed regions, as well as favourable
factors from sunflower, contributed to the level of Phomopsis resistance in cultivated sunflower.
Received: 28 June 1996 / Accepted: 5 July 1996 相似文献
11.
Polymorphism, distribution, and segregation of AFLP markers in a doubled haploid rice population 总被引:18,自引:0,他引:18
M. Maheswaran P. K. Subudhi S. Nandi J. C. Xu A. Parco D. C. Yang N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):39-45
We exploited the newly developed amplified fragment length polymorphism (AFLP) technique to study the polymorphism, distribution
and inheritance of AFLP markers with a doubled haploid rice population derived from ‘IR64’/‘Azucena’. Using only 20 pairs
of primer combinations, we detected 945 AFLP bands of which 208 were polymorphic. All 208 AFLP markers were mapped and distributed
over all 12 chromosomes. When these were compared with RFLP markers already mapped in the population, we found the AFLP markers
to be highly polymorphic in rice and to follow Mendelian segregation. As linkage map of rice can be generated rapidly with
AFLP markers they will be very useful for marker-assisted backcrossing.
Received: 11 April 1996 / Accepted: 14 June 1996 相似文献
12.
A. van Tuinen M. Koornneef M. -M. Cordonnier-Pratt L. H. Pratt R. Verkerk P. Zabel 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):115-122
The map positions of five previously described phytochrome genes have been determined in tomato (Lycopersicon esculentum Mill.) The position of the yg-2 gene on chromosome 12 has been confirmed and the classical map revised. The position of the phytochrome A (phy A)-deficient
fri mutants has been refined by revising the classical map of chromosome 10. The position of the PhyA gene is indistinguishable from that of the fri locus. The putative phyB1-deficient tri mutants were mapped by classical and RFLP analysis to chromosome 1. The PhyB1 gene, as predicted, was located at the same position. Several mutants with the high pigment (hp) phenotype, which exaggerates phytochrome responses, have been reported. Allelism tests confirmed that the hp-2 mutant is not allelic to other previously described hp (proposed here to be called hp-1) mutants and a second stronger hp-2 allele (hp-2
j
) was identified. The hp-2 gene was mapped to the classical, as well as the RFLP, map of chromosome 1.
Received: 24 May 1996 / Accepted: 14 June 1996 相似文献
13.
RFLP mapping of resistance to chlorosis induction by Pyrenophora tritici-repentis in wheat 总被引:2,自引:0,他引:2
J. D. Faris J. A. Anderson L. J. Francl J. G. Jordahl 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):98-103
Tan spot, caused by Pyrenophora tritici-repentis, is an economically important disease in major wheat production areas. The fungus can produce two genetically distinct symptoms
on leaves of susceptible wheat genotypes: tan necrosis (nec) and extensive chlorosis (chl). Our objectives were to determine
the number of genes conditioning resistance to tan spot in a population of wheat recombinant inbred lines, and map the chromosomal
location of the resistance genes using RFLPs. Conidia produced by the P. tritici-repentis isolate Pti2 (nec+chl+) were used to inoculate seedlings of 135 recombinant inbred lines derived from the cross of the synthetic
hexaploid wheat W-7984 with Opata 85. A subset of the population was inoculated with conidia produced by the isolates D308
(nec−chl+) and 86-124 (nec+chl−). Inoculated seedlings were rated on a scale of 1 to 5 based on lesion type. Necrosis-inducing
culture filtrate produced by the isolate 86-124 was also used to screen the entire population. A map consisting of 532 markers
was employed to identify significant associations between marker loci and tan spot resistance. The entire population was insensitive
to culture filtrate produced by the isolate 86-124, and the entire subset was resistant to conidial inoculation of the same
isolate. The population segregated for reaction to isolates D308 and Pti2, indicating that this population segregates for
resistance to extensive chlorosis only, and not to tan necrosis. RFLP analysis indicated the presence of a gene with a major
effect in 1AS, a gene with a minor effect in 4AL, and an interaction between the 1AS gene and a gene in 2DL. Together, these
loci explained 49.0% of the variation in this population for resistance to tan spot produced by the isolate Pti2. Two regions
one in 1BL and one in 3BL, were significantly associated with resistance to extensive chlorosis, but were not significant
in the multiple regression model. It should be feasible to introgress these resistance loci into adapted genetic backgrounds
by using a marker-assisted selection scheme.
Received: 30 March 1996 / Accepted: 31 May 1996 相似文献
14.
B. Hui Liu S. J. Knapp D. Birkes 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):8-19
Genetic correlations are frequently estimated from natural and experimental populations, yet many of the statistical properties of estimators
of are not known, and accurate methods have not been described for estimating the precision of estimates of Our objective was to assess the statistical properties of multivariate analysis of variance (MANOVA), restricted maximum
likelihood (REML), and maximum likelihood (ML) estimators of by simulating bivariate normal samples for the one-way balanced linear model. We estimated probabilities of non-positive
definite MANOVA estimates of genetic variance-covariance matrices and biases and variances of MANOVA, REML, and ML estimators
of and assessed the accuracy of parametric, jackknife, and bootstrap variance and confidence interval estimators for MANOVA estimates of were normally distributed. REML and ML estimates were normally distributed for but skewed for and 0.9. All of the estimators were biased. The MANOVA estimator was less biased than REML and ML estimators when heritability
(H), the number of genotypes (n), and the number of replications (r) were low. The biases were otherwise nearly equal for different estimators and could not be reduced by jackknifing or bootstrapping.
The variance of the MANOVA estimator was greater than the variance of the REML or ML estimator for most H, n, and r. Bootstrapping produced estimates of the variance of close to the known variance, especially for REML and ML. The observed coverages of the REML and ML bootstrap interval estimators
were consistently close to stated coverages, whereas the observed coverage of the MANOVA bootstrap interval estimator was
unsatisfactory for some H,
n, and r. The other interval estimators produced unsatisfactory coverages. REML and ML bootstrap interval estimates were narrower
than MANOVA bootstrap interval estimates for most H, and r.
Received: 6 July 1995 / Accepted: 8 March 1996 相似文献
15.
M. Mohan P. V. Sathyanarayanan A. Kumar M. N. Srivastava S. Nair 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):777-782
A PCR-based marker (E20570) linked to the gene Gm4t, which confers resistance to a dipteran pest gall midge (Orseolia oryzae), has been mapped using the restriction fragment length polymorphism (RFLP) technique in rice. Gm4t is a dominant resistance gene. We initially failed to detect useful polymorphism for this marker in a F3 mapping population derived from a cross between two indica parents, ‘Abhaya’בShyamala’, with as many as 35 restriction enzymes. ‘Abhaya’ carries the resistance gene Gm4t and ‘Shyamala’ is susceptible to gall midge. Subsequently, E20570 was mapped using another mapping population represented by a F2 progeny from a cross between ‘Nipponbare’, a japonica variety, and ‘Kasalath’, an indica variety, in which the gene Gm4t was not known to be present. Gm4t mapped onto chromosome 8 between markers R1813 and S1633B. Our method, thus, presents an alternative way of mapping genes
which otherwise would be difficult to map because of a lack of polymorphism between closely related parents differing in desired
agronomic traits.
Received: 1 April 1997 / Accepted: 13 May 1997 相似文献
16.
C. Conicella G. Genualdo R. Lucia K. S. Ramulu T. Cardi 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(4):609-617
Somatic hybridization between Solanum commersonii and S. tuberosum resulted in the production of male-sterile hybrid plants, except for one fully male-fertile hybrid. The male-sterile hybrids
exhibited a“pollen-less” phenotype, with rare pollen grains which were abnormal in shape and exine sculpture. Microsporogenesis
and tapetal development were investigated both in male-sterile and male-fertile somatic hybrids to assess the cytological
events that were involved in male sterility. The pattern of male sterility was complex, arising through mechanisms expressed
at both sporophytic and gametophytic levels. Various abnormalities occurred first in the tapetum, and later during meiosis-II
and cytokinesis. These caused the degeneration of the sporads and of the microspores when they were released. In the male-fertile
hybrid, normal development of the tapetum and pollen mother cells was restored. The hypothesis that tapetal breakdown, meiosis-II
and cytokinesis defects are related to each other, and depend on nuclear-mitochondrial interactions, is discussed. Because
of the formation of multivalent chromosome configurations, it is likely that gene exchange between S. commersonii and S. tuberosum can occur in somatic hybrids, offering potential perspectives for the introgression of useful traits from S. commersonii into S. tuberosum.
Received: 10 December 1996/Accepted: 21 March 1997 相似文献
17.
R. E. Voorrips M. C. Jongerius H. J. Kanne 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):75-82
A genetic map covering 615 cM in 12 linkage groups was assembled based on 92 RFLP and AFLP markers segregating in a population
of 107 doubled haploid lines (DH lines) of Brassica oleracea. The DH-line population was obtained through microspore culture from the of two homozygous parents: DH-line Bi derived from the cabbage landrace Bindsachsener, and DH-line Gr from broccoli cv ‘Greenia’.
Sixty-five percent of the loci, and in some cases complete linkage groups, displayed distorted segregation ratios, a frequency
much higher than that observed in populations of the same species. DH-line Bi was resistant to clubroot, which is caused by a Dutch field isolate of Plasmodiophora brassicae. Resistance in the DH-line population was determined in two ways: by assigning symptom grades to each plant, and by measuring
the fresh weights of the healthy and affected parts of the root system of each plant. Using a multiple QTL mapping approach
to analyze the fresh weight data, we found two loci for clubroot resistance; these were designated pb-3 and pb-4. The additive effects of these loci were responsible for 68% of the difference between the parents and for 60% of the genetic
variance among DH-line means. Also, indications for the presence of two additional, minor QTLs were found. Analysis of symptom
grades revealed the two QTLs pb-3 and pb-4, as well as one of the two minor QTLs indicated by analysis of the fresh weight data.
Received: 29 April 1996 / Accepted: 10 May 1996 相似文献
18.
Liangming Chen Zhigang Zhao Xi Liu Linglong Liu Ling Jiang Shijia Liu Wenwei Zhang Yihua Wang Yuqiang Liu Jianmin Wan 《Molecular breeding : new strategies in plant improvement》2011,27(2):247-258
The incomplete fertility of japonica × indica rice hybrids has inhibited breeders’ access to the substantial heterotic potential of these hybrids. As hybrid sterility
is caused by an allelic interaction at a small number of loci, it is possible to overcome it by simple introgression at the
major sterility loci. Here we report the use of marker-assisted backcrossing to transfer into the elite japonica cv. Zhendao88 a photoperiod-sensitive male sterility gene from cv. Lunhui422S (indica) and the yellow leaf gene from line Yellow249 (indica). The microsatellite markers RM276, RM455, RM141 and RM185 were used to tag the fertility genes S5, S8, S7 and S9, respectively. Line 509S is a true-breeding photoperiod-sensitive male sterile plant, which morphologically closely resembles
the japonica type. Genotypic analysis showed that the genome of line 509S comprises about 92% japonica DNA. Nevertheless, hybrids between line 509S and japonica varieties suffer from a level of hybrid sterility, although the line is highly cross-compatible with indica types, with the resulting hybrids expressing a significant degree of heterosis. Together, these results suggest that segment
substitution on fertility loci based on known information and marker-assisted selection are an effective approach for utilizing
the heterosis of rice inter-subspecies. 相似文献
19.
Geographic distribution and multilocus organization of isozyme variation of rice (Oryza sativa L.) 总被引:5,自引:0,他引:5
Z. Li J. N. Rutger 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(3):379-387
Genetic organization of isozyme variation in rice (Oryza sativa L.) was investigated based on 17 polymorphic isozyme loci using a sample of 511 accessions of worldwide origin. The genetic
diversity within the species was very high (H=0.36 with 4.82 alleles per locus), as compared with most selfing plant species.
Three diversity centers were detected for isozyme variation including South Asia, China and Southeast Asia. The accessions
were classified into three well-differentiated cultivar groups corresponding to the indica and japonica subspecies, and a new unnamed group. Variation within the cultivar groups accounted for 80% of the total isozyme variation.
Within-country variation accounted for 58% of the total variation while among-region and among-country variation within the
cultivar groups accounted for only 14% and 8% of the total variation. Analyses using log-linear models revealed that pronounced
non-random associations between and among alleles at many unlinked isozyme loci were organized in a non-hierarchical pattern,
and subspecific and macro-geographic differentiation was much more pronounced in multilocus phenotype frequencies than in
allelic frequencies at individual loci. These results suggest that selection on multilocus gene complexes was largely responsible
for the maintenance of the extensive isozyme variation within the species and the indica-japonica differentiation. Our results further suggest the independent domestication of indica and japonica, the dual origins of the indica rice from China and South Asia (India), and the differentiation of the ecotypes ’javanica’ and the ’temperate japonica’ within the japonica subspecies.
Received: 5 August 1999 / Accepted: 13 December 1999 相似文献
20.
A. H. Price A. D. Tomos D. S. Virk 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(1-2):132-142
Root growth is an important component of the adaptation of rice to drought-prone environments. A hydroponic screen was used
to study root growth of 28 rice varieties. Both maximum root length and adventitious root thickness varied widely between
varieties. In general, japonica varieties had larger root systems than indica varieties. Two F2 populations involving the thick- and long-rooted upland japonica variety ‘Azucena’ and two poor-rooting varieties, namely the upland indica‘Bala’ and the Italian japonica‘Maratelli’, were made and screened in hydroponics. Generation means analysis revealed significant additive and dominance
main effects for the root length traits with a prevalence of dominance gene effects in both crosses. The dominance×dominance
type of non-allelic interactions were important for maximum root length from day 7 to day 28, root volume, root thickness
and root cell length in the cross ‘Bala’בAzucena’. The heritability (broad-sense) estimates varied from low to high for the
traits and displayed differences between populations. This suggested that recombinant lines with improved root traits can
be developed from the two crosses with selection methods that involve some form of progeny evaluation. In a companion paper,
we report the mapping of quantitative trait loci (QTLs) for root growth traits in the ‘Bala’בAzucena’ population using restriction
fragment length polymorphisms (RFLPs).
Received: 5 May 1996 / Accepted: 14 February 1997 相似文献