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991.
Basagoudanavar S.H. Rao J.R. Singh R.K. Butchaiah G. 《Veterinary research communications》1999,23(4):249-255
The total genomic DNAs from Trypanosoma evansi isolates of bubaline, equine and cameline origin were amplified by polymerase chain reaction using eight arbitrarily selected 10-base primers. Informative band patterns were obtained for all isolates analysed. Depending upon the T. evansi isolate–primer combination, between 1 and 11 reproducible DNA fingerprints of 205 to 3016 bp were amplified, suggesting minor and major differences in their RAPD (random amplified polymorphic DNA) profiles. 相似文献
992.
If we are to breed common bean (Phaseolus vulgaris L.) for durable resistance to diseases, we must understand pathogenic variation
and find sources of resistance. Our first objective was to determine the patterns of pathogenic variation found among isolates
of Phaeoisariopsis griseola (PG), the fungus that causes angular leaf spot (ALS) in common bean. We characterized 433 PG isolates
from 11 Latin American and 10 African countries, using differential cultivars, isozymes, and/or random amplified polymorphic
DNA (RAPD) markers. We also systematically screened, for ALS resistance, common bean accessions from the world collection
held at CIAT, and assessed the progress so far made in breeding for resistance to ALS. Despite their great diversity within
and between countries on both continents, the PG isolates were classified into two major groups: Andean, and Middle American.
Although each group had internal differences for virulence, and biochemical and molecular characteristics, the ‘Andean’ PG
isolates were more virulent on common beans of Andean origin, than on those of Middle American origin, thus, suggesting a
host-pathogen co-evolution. The ‘Middle American’ PG isolates, although more virulent on common beans from Middle America,
also attacked Andean beans, thus, exhibiting a much broader virulence spectrum. To find sources of resistance, we tested 22,832
common bean accessions against naturally occurring PG isolates in the field at CIAT's Experiment Station, Quilichao, Colombia,
between 1985 and 1992. The resulting 123 intermediate (scores of 4 to 6) and resistant (scores of 1 to 3) accessions were
then tested in the greenhouse against selected 14 PG isolates of diverse origins. Nineteen accessions were intermediate or
resistant to at least 13 of 14 PG isolates. Similarly, of 13,219 bred lines tested in the field between 1978 and 1996, 89
were intermediate or resistant. Of these, 33 bred lines proved intermediate or resistant to at least eight of nine PG isolates
to which they were challenged in the greenhouse. We suggest that, to breed for durable resistance to ALS, common bean populations
should be developed from crosses between Andean and Middle American gene pools. The populations should then be systematically
evaluated and selected against the broadest range of the most virulent PG isolates of diverse evolutionary origins.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
993.
WeiKuan Gu JiaQian Zhu Donald H. Wallace Shree P. Singh Norman F. Weeden 《Euphytica》1998,102(1):125-132
The genetic basis of the photoperiod response in common bean (Phaseolus vulgaris L.) was investigated using DNA markers and
recombinant inbred populations. Two loci affecting photoperiod response were resolved, the previously defined primary locus
(Ppd), at which the dominant allele confers sensitivity to photoperiod, and a second locus (herein defined as Hr), which influences
the degree to which a plant responds to photoperiod. The DNA marker P51600 cosegregated with the recessive allele, ppd, displaying a recombination frequency with the photoperiod locus of about 3%.
A second marker, B303600, was linked to the recessive allele at Hr and mapped approximately 13 cM from this locus. The markers demonstrated that in
crosses involving Redkloud and several photoperiod sensitive lines, insensitivity to photoperiod is primarily controlled by
ppd and that Hr does not significantly affect flowering time in ppd/ppd plants under the environmental conditions used.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
994.
One-hundred and sixty-seven accessions belonging to 13 wild Oryza species were screened against the bacterial leaf blight (BB) pathogen (Xanthomonas oryzae pv. oryza) in Punjab, India. Nine species were identified as carrying resistant genes against the four most prevalent pathotypes under conditions in Punjab. These included O. barthii (eight accessions), O. longistaminata (five accessions), O. meridionalis (three accessions), O. nivara (five accessions), O. rufipogen (two accessions), and one accession each from O. punctata, O. minuta, O. malampuzhaensis and O. latifolia. This is the first report showing the availability of BB resistance in two species namely, O. meridionalis and O. punctata. The resistant accessions, especially those with a similar genome (AA) could potentially be used for the transfer of BB resistance to well-adapted high-yielding rice cultivars. 相似文献
995.
Water, Air, &; Soil Pollution - Application of soluble forms of nitrogen (N) fertilizers to citrus trees in sandy soils of central Florida may cause leaching of NO 3 ? below the rooting... 相似文献
996.
Distribution of rainfall and soil moisture content in the soil profile under citrus tree canopy and at the dripline 总被引:2,自引:0,他引:2
The plant canopy intercepts rain and thus can alter the distribution of water under the canopy as compared to that along
the dripline. The effects of a citrus (Citrus sinensis L. Osbeck) tree (25-year-old, Valencia orange) canopy on the distribution of rainfall and soil moisture content within the
soil profile either along the dripline (D) or under the canopy near the trunk (inner side; I), and midway between I and Dripline
(M) were evaluated, on the east and west sides of trees planted along north-south rows. Results of eleven storm events in
1995 (mean of east and west sides) revealed that the amounts of precipitation at the D, M, and I positions were 97–140, 47–94,
and 52–79% of the incident rainfall, respectively. Thus, canopy interception of incident rainfall was quite appreciable. The
soil moisture content was greater along the dripline compared to that at the M and I positions, particularly in the deeper
(≥60 cm) soil profile. The water flux was significantly greater at the dripline than under the canopy indicating a greater
leaching potential of soil-applied fertilizers and other chemicals when placed along the dripline. A substantial reduction
in the rainfall and water flux under the canopy as a result of canopy interception suggests that application of fertilizer
and chemicals under the canopy could minimize leaching losses.
Received: 10 November 1997 相似文献
997.
Following screening, selection, characterization and examination of their symbiotic N2 fixation, only two Rhizobium strains (ND-16 and TAL-1860) and four lentil genotypes (DLG-103, LC-50, LC-53 and Sehore 74-3) were found to be suited to
sodic soils. Interactions between salt-tolerant lentil genotypes and Rhizobium strains were found to be significant, and resulted in greater nodulation, N2 fixation (nitrogenase activity), total nitrogen, plant height, root length and grain yield in sodic soils under field conditions
compared to uninoculated controls. Significantly more nodulation, nitrogenase activity, glutamine synthetase (GS) and NADH-dependent
glutamate synthase (NADH-GOGAT) activities were found in normal soil as compared to the soil supplemented with 4% and 8% NaCl.
Salt stress inhibited nitrogenase, GS and NADH-GOGAT activities. However, nitrogenase activity in nodules was more sensitive
to salt stress than GS and NADH-GOGAT activities (NH4
+ assimilation). The relevance of these findings for salt-tolerant symbionts is discussed.
Received: 14 November 1997 相似文献
998.
A new flavonoid, 3,7-dihydroxy-8-methoxyflavone 7-O-α-
-rhamnopyranosyl-(1→4)-α-
-rhamnopyranosyl-(1→6)-β-
-glucopyranoside (1), was isolated from the seeds of Shorea robusta. 相似文献
999.
Flow properties, clarity and composition of concentrates (retentates) and clarified syrup (permeates) obtained by membrane microfiltration of saccharified corn starch hydrolysate were determined. Clarified syrup (permeate) had low color and no suspended solids at all volume concentration ratios (VCRs) up to 100 X. The color and suspended solids in the concentrate increased linearly with increase in volume concentration ratio. Viscosity of the concentrates increased at higher VCR, but the viscosity of permeates remained essentially unchanged. The densities of all retentates and permeates were not significantly different from each other. Dextrose content of retentates and permeates at all VCRs did not change significantly during the microfiltration, averaging 28·90±1·01% w/w. Total solids, nitrogen, fat and ash content of the retentates increased with increase in VCR. In contrast, total solids, nitrogen, fat and ash of the permeates remained the same for all VCRs, averaging 29·44, 0·011, 0·07 and 0·042% respectively. 相似文献
1000.
M. Prakash P. Haridasa Rao N.S. Susheelamma J.V. Prabhakar 《Journal of Cereal Science》1998,28(3):281-289
Several Indian snack foods consist of an outer coating made with a wheat flour batter and a sweet or savoury filling. In order to study the possibilities of improving the rheological characteristics of batters used in the batter-coated products, wheat flour was steamed for varying periods of time (5, 15 and 30 min). The studies indicated that SDS-sedimentation values decreased from 35 to 24·5 mL, gluten forming protein was completely denatured, gel mobility increased and solubility of gliadin in the β-region decreased with an increase in the steaming period.The steamed wheat flour was used to make batters having 30, 33 and 36% solids suspended in water. The apparent viscosities of the batter increased from 9·6 to 19·2 Pa·s; the yield stress increased from 5·3 to 7·15 Pa; the consistency index increased from 27·86 to 78·31 Pa·sn. The maximum values of all three parameters were observed in the batter which had a solids concentration of 36%, and which had been made with a flour steamed for 30 min. On the other hand, the flow behaviour index decreased slightly with duration of steaming and with increasing solid concentrations in the batter. 相似文献