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131.
C.J. Liu 《Euphytica》1997,98(1-2):21-27
A large number of S. scabra accessions have been accumulated worldwide. The majority of them were collected from Brazil and
most of the others came from either Colombia or Venezuela. One hundred of these accessions, selected to represent the geographical
distribution of the S. scabra collection held at the Australian Tropical Forages Genetic Resource Centre, were analysed using
RAPD as markers. Seven of these accessions were found not to be S. scabra. Of the S. scabra accessions, the average dissimilarity
value among Brazilian accessions (0.053) was much lower than that among Colombian (0.074) or Venezuelan (0.088) accessions,
with an overall dissimilarity value of 0.059 among all the S. scabra accessions. Based on their dissimilarity values, most
of these accessions could be separated into five groups. Geographical distributions for most accessions in each of these groups
were well defined. Limited long distance introductions/dispersions of S. scabra between these regions were detected and they
were mainly confined to Brazilian genotypes. The clustering results based on RAPD were compared with those based on morphological-agronomical
characters, and the groups produced by the two different methods did not always match. Possible reasons for this discrepancy
are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
132.
Cultivars of common bean (Phaseolus vulgaris L.) capable of yielding well at low levels of native or added phosphorus (P)
are highly desirable in many tropical production systems. The objective of the present study was to identify geographical
regions which might be sources of such genotypes. A total of 364 landraces, cultivars and wild genotypes, drawn from a broad
geographic range, were divided on the basis of growth habit into four field trials, each comprising two levels of P, stressed
and unstressed, on an infertile Andosol in Popayan, Colombia. The regression relationship between grain yield per plant in
the presence and in the absence of stress was determined, and each genotype's deviation from this relationship was used as
a measure of P-efficiency. There was highly significant variation in efficiency among genotypes in all growth habits, and
in climbing beans there were consistent regional differences, superior genotypes being identified with greater frequency among
those from Bolivia, West Mexico and South Mexico-West Guatemala. The latter region was promising for prostrate bush genotypes
also. Wild beans in general performed relatively poorly; it appears that P-efficiency traits in P. vulgaris have been acquired
during or after domestication. These results confirm that genetic differences in P-efficiency exist among common bean genotypes
and suggest that these are related to geographic origin. Furthermore, the use of a representative sample of germplasm can
help to identify segments of the gene bank that are especially promising as sources of desirable traits.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
133.
Summary As the exploitation of economic characters in potato is reaching a plateau, use of exotic germplasm offers an ideal opportunity for further improvement. Fifty-five accessions from eleven countries were studied under long and short day conditions. Wide variation was noticed for a number of phenological, morphological and tuber characters. Analysis of variation and correlations has demonstrated possibilities for using this diverse germplasm in various potato improvement programs.Abbreviations APC -
Andean Primitive Cultivars
- AUDPC -
Area Under Disease Progress Curve
- CCBL -
Commerical Cultivars and Breeding Lines
- LD -
Long Days
- SD -
Short Days 相似文献
134.
Summary Soybean germplasm was screened for resistance to bacterial pustule disease. The etiological agent, Xanthomonas campestris pv. glycines, was isolated from the leaves of field grown soybean in Maharashtra, India. The screening of soybean stocks was carried out by excised leaf inoculation method. A differential susceptibility to the pathogen was observed in the tested stocks. Two stocks P-4-2 and P-169-3 were found to be completely resistant to the pathogen and displayed an incompatible reaction. Four cultivars, EC-34160, Bragg, Kalitur and PK-472 displayed moderate resistance and the remaining stocks were susceptible to the attack of the pathogen. The stocks P-4-2 and P-169-3 remained resistant even to a high concentration of 109 colony forming units (cfu)/ml of the pathogen. 相似文献
135.
Summary Methods developed to identify genetically diverse varieties of beans (Phaseolus vulgaris L.) were applied to closely related lines that were difficult to distinguish on the basis of seed morphology. Seedling tissues and seeds of black beans, were examined electrophoretically for isoenzyme and cotyledon proteinn protein patterns. Seven enzymes, extracted from seeds or from seedling stem, root or leaf tissues, were compared for polymorphism. Peptidase, polyphenol oxidase, phosphoglucoisomerase and glutamate oxaloacetate transaminase patterns were the same for all lines. Some differences were observed for acid phosphatase, peroxidase and esterase patterns, but complete discrimination of the six selected lines was not possible on the basis of isoenzyme patterns alone. Using polyacrylamide gel electrophoresis (PAGE) of dissociated 0.1 M acetic acid soluble proteins at pH 3.1 (acid-PAGE), or sodium dodecyl sulphate PAGE (SDS-PAGE) of residual protein extracts, all but one pair of samples in each case could be distinguished from the other samples. Using both techniques all of the lines could be identified unequivocally. 相似文献
136.
Summary A landrace seed lot of runner bean (Phaseolus coccineus L.), obtained from the Budapest region, Hungary, was separated into five seed groups according to seed coat colour. 131 plants were grown randomly, and observed for 27 morphological and physiological characters. The collected data were analysed by ANOVA.Numerical taxonomy of the data employed Principal Components Analysis to generate scatter diagrams and Cluster Analysis to generate dendrograms, both before and after removing data on the four anthocyanin colour characters (seed coat, calyx, stem and flower colour) as these characters are probably controlled by a single major gene. The progenies from the five distinct parental seed groups showed much overlap in characteristics, indicating that they were not distinct lines but comprised a largely panmictic population.Some character associations were detected: plants from white seeds matured significantly later than those from black seeds, plants from white seeds with a few dark spots produced seeds significantly heavier than average, whereas those from white or black seeds produced significantly lighter seeds, although the average seed yield per plant did not differ significatly. 相似文献
137.
J. A. Lane T. H. M. Moore D. V. Child K. F. Cardwell B. B. Singh J. A. Bailey 《Euphytica》1993,72(3):183-188
An in vitro growth system was used to determine the virulence of two samples of Striga gesnerioides from Zakpota in southern Benin. Cowpea variety B301, previously considered resistant to all races of S. gesnerioides, was susceptible to both samples of the parasite. Two other cowpea varieties, 58–57 and IT81D-994, were totally resistant. Resistance in 58–57 was associated with a hypersensitive necrosis of infected roots, whilst IT81D-994 supported production of small S. gesnerioides tubercles with stems which failed to develop. Striga gesnerioides from southern Benin is the fourth race of the parasite to be identified, and the first with virulence on variety B301. The implications for breeding cowpeas with resistance to S. gesnerioides are discussed.Abbreviations IITA
International Institute of Tropical Agriculture
- LARS
Long Ashton Research Station
- SAFGRAD
Semi-Arid Food Grain Research and Development 相似文献
138.
Application of RAPD markers in the characterisation of Chrysanthemum varieties and the assessment of somaclonal variation 总被引:1,自引:0,他引:1
Characterisation of fifteen commercial varieties of Chrysanthemum was carried out through RAPD analysis. Varieties could be distinguished from each other and the level of similarity between
varieties seemed to be not very high. In vitro cultures were establish from four varieties and were subjected to different proliferation conditions. Five individuals from
each variety and treatment were analysed using RAPD at the beginning of the treatment and after a month of culture. Variation
was detected at both stages of the culture period. The rate of variation found showed differences between varieties, but no
significant difference was found between culture conditions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
139.
Highly inbred B line of cucumber was used to compare the effect of four types of in vitro culture on somaclonal variation. The plants were regenerated from the following types of culture: twelve- and eighteen-month-old
liquid culture of meristematic clumps (LMC12(18)), ten-month-old embryogenic cytokinin-dependent suspension (CDS), eighteen-month-old embryogenic cytokinin-dependent suspension
in medium with modified NH+
4/NO3
- ratio (CDS 1.7), twelve-month-old embryogenic auxin-dependent suspension (ADS), thirty six-month-old embryogenic auxin-dependent
suspension in medium with modified NH+
4/NO3
- ratio (ADS 1.7) and recurrent leaf callus regeneration (RLC) – repeated 5 times. The differences in the incidence of the
following properties were observed: the ploidy of R0 plants, the segregation of new morphological traits in R1 and the germination ability of R1 seeds. R1 families with the segregation of new phenotypes were most numerous in CDS (62.5%) and LMC18 (57.9%), next in CDS1.7 (35.7%), while the smallest number was found in LMC12 (11.1%) and RLC (3.4%).Tetraploid and mixoploid plants occurred in ADS1.7 and ADS (100%) whereas CDS and RLC were observed
to contain only tetraploids, respectively 33.3% and 55.2%. There were no changes of ploidy after LMC12, LMC18 and CDS1.7. Among new phenotypes there were such that have not been described so far in cucumber: ginkgolike leaf (gll),
yellow-green chlorophyll mutants (y-gc), serrate margin of corolla in male and female flowers (smc).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
140.
Anton C. Zeven 《Euphytica》2002,123(2):147-158
Maintenance breeding of landraces is discussed. Various practical andtheoretical advices, presented in the literature to collectors of genebankshave been used to compare these with the methods applied by farmers.Although most farmers realize the utmost importance of yield stability, theyand their ancestors experienced that maintenance breeding could better bereplaced by seed replacement. A few crops such as rootstock rose andespecially maize, form exceptions. In these crops the farmers actually collect`hips', or ears for the next generation. However, they also apply seedreplacement from time to time.More research is needed to obtain better knowledge about the level ofvariation of a landrace grown for various generations before and after seedreplacement. 相似文献