3,339 research outputs found
Molecular Mapping of a Male-Sterile Gene in Soybean
A newly identified genie male-sterile mutant in soybean [Glycine max (L.) Merr.] has high seed set under natural field conditions and is potentially useful in breeding programs. Meiosis is normal in the mutant line. Sterility in this mutant is caused by failure of cailose dissolution at the tetrad stage, which results in microspore abortion; however, little is known about the male-sterile gene at the molecular level. The objective of this study was to identify molecular markers linked with the male-sterile gene (ms) and to place the ms gene onto the soybean molecular genetic map. An F2 population of 107 individuals was constructed from a cross between the mutant msMOS (ms ms) and the cultivar Minsoy (Ms Ms). Two hundred seventy markers, including 219 RFLP and 51 SSRs, were evaluated. Of these, 102 RFLP probes and 31 SSR markers detected polymorphisms between the parents. The F2 population was screened for segregation of these polymorphic molecular markers. Analyses revealed that the male-sterile locus, designated ‘ms’, was located on linkage group D1b of the USDA/ISU soybean molecular genetic map. The availability of linked DNA markers will facilitate the genetic analysis of this male-sterility gene in relation to soybean breeding programs, and will be a starting point for the isolation of the ms gene by map-based cloning
Fr1 (root fluorescence) locus is located in a segregation distortion region on linkage group K of soybean genetic map
We report the use of bulked segregant SSR analysis for rapid identification of DNA markers linked to the Fr1 locus in soybean. Pooled DNA extracts from 10 homozygous Fr1 Fr1 and 10 fr1 fr1 F2 plants, derived from a msMOS x Minsoy cross, were analyzed using 65 SSR markers. Five SSRs produced repeatable polymorphisms between paired bulks. Linkage with the Fr1 locus was tested using these five SSR primers and DNA from individual plants of each bulk. DNA polymorphisms generated by these five primers were linked to the Fr1 locus. Linkage of SSR loci with the Fr1locus was verified by using an F2 population segregating for Fr1. The five SSR markers and Fr1 are on linkage group K of the USDA ARS/ISU molecular genetic map. The markers flanking Fr1 are Satt337 (11.0 cM) and Satt044 (0.6 cM). Fr1 previously was mapped on linkage group 12 of the classical genetic map. Thus classical genetic linkage group 12 has been correlated to linkage group K of the molecular genetic map. Six SSR markers were chosen on linkage group K to test the segregation ratio. All six SSRs tested were skewed toward the Minsoy genotype, one chi-square value was statistically significant. This suggested that a gametophyte factor may lie in the region close to Fr1 and most likely close to Satt046
Discovery of a very X-ray luminous galaxy cluster at z=0.89 in the WARPS survey
We report the discovery of the galaxy cluster ClJ1226.9+3332 in the Wide
Angle ROSAT Pointed Survey (WARPS). At z=0.888 and L_X=1.1e45 erg/s (0.5-2.0
keV, h_0=0.5) ClJ1226.9+3332 is the most distant X-ray luminous cluster
currently known. The mere existence of this system represents a huge problem
for Omega_0=1 world models.
At the modest (off-axis) resolution of the ROSAT PSPC observation in which
the system was detected, ClJ1226.9+3332 appears relaxed; an off-axis HRI
observation confirms this impression and rules out significant contamination
from point sources. However, in moderately deep optical images (R and I band)
the cluster exhibits signs of substructure in its apparent galaxy distribution.
A first crude estimate of the velocity dispersion of the cluster galaxies based
on six redshifts yields a high value of 1650 km/s, indicative of a very massive
cluster and/or the presence of substructure along the line of sight. While a
more accurate assessment of the dynamical state of this system requires much
better data at both optical and X-ray wavelengths, the high mass of the cluster
has already been unambiguously confirmed by a very strong detection of the
Sunyaev-Zel'dovich effect in its direction (Joy et al. 2001).
Using ClJ1226.9+3332 and ClJ0152.7-1357 (z=0.835), the second-most distant
X-ray luminous cluster currently known and also a WARPS discovery, we obtain a
first estimate of the cluster X-ray luminosity function at 0.8<z<1.4 and
L_X>5e44 erg/s. Using the best currently available data, we find the comoving
space density of very distant, massive clusters to be in excellent agreement
with the value measured locally (z<0.3), and conclude that negative evolution
is not required at these luminosities out to z~1. (truncated)Comment: accepted for publication in ApJ Letters, 6 pages, 2 figures, uses
emulateapj.st
The WARPS survey - IV: The X-ray luminosity-temperature relation of high redshift galaxy clusters
We present a measurement of the cluster X-ray luminosity-temperature relation
out to high redshift (z~0.8). Combined ROSAT PSPC spectra of 91 galaxy clusters
detected in the Wide Angle ROSAT Pointed Survey (WARPS) are simultaneously fit
in redshift and luminosity bins. The resulting temperature and luminosity
measurements of these bins, which occupy a region of the high redshift L-T
relation not previously sampled, are compared to existing measurements at low
redshift in order to constrain the evolution of the L-T relation. We find a
best fit to low redshift (z1 keV, to be L proportional
to T^(3.15\pm0.06). Our data are consistent with no evolution in the
normalisation of the L-T relation up to z~0.8. Combining our results with ASCA
measurements taken from the literature, we find eta=0.19\pm0.38 (for Omega_0=1,
with 1 sigma errors) where L_Bol is proportional to (1 + z)^eta T^3.15, or
eta=0.60\pm0.38 for Omega_0=0.3. This lack of evolution is considered in terms
of the entropy-driven evolution of clusters. Further implications for
cosmological constraints are also discussed.Comment: 11 pages, 7 figures, accepted for publication in MNRA
Insect-mediated cross-pollination in soybean [Glycine max (L.) Merrill] : I. Agronomic performance
In soybean, manual cross-pollination to produce large quantities of F1 hybrid seed for yield trials is difficult and time-consuming. Conversely, insect-mediated cross-pollination has been shown to produce large quantities of hybrid seed in soybean and could facilitate the identification of heterotic patterns. The objective of our study was: (1) evaluate F1hybrid soybean plants from single crosses for yield and agronomic traits over several environments and (2) compare hybrid performance of the single crosses to lines developed from three-way crosses and backcrosses. In 2003, F1 seed of single-crosses and their parent lines were evaluated in replicated experiments at three locations. Also in 2003, three-way crosses, and BC1F1 seed were produced. In 2004, three-way crosses, BC1F1 crosses, and their parent lines were evaluated at one location. High-parent heterosis (HPH) in single-crosses for grain yield ranged from −41.11% to +11.19%; for protein content from −4.34% to +3.53%, and for oil content from −13.22% to −0.84%. In three-way crosses, HPH for yield ranged from −25.21% to −4.50%, for protein from −2.72% to +1.92%, and for oil from −5.87% to −1.20%. For BC1F1 crosses, HPH for yield ranged from −15.65% to +41.97%, for protein from −2.57% to +1.69%, and for oil from −2.47% to +2.22%. Although positive heterosis levels were observed across all populations tested to determine the economic feasibility it is imperative that more tests of more cross-combinations be evaluated in replicated environments. Extensive research in different environments must be conducted to determine what parental combinations will produce the highest heterosis levels, and to develop criteria for selecting the parents with the best combining ability. This will be important to maximize agronomic performance that can economically justify the use of hybrids in soybean production
Studies of thermionic materials for space power applications informal monthly report, oct. 1 - oct. 31, 1963
Thermionic space power material - isostatic pressing, vapor deposited tungsten, high temperature properties, cesium thermionic cell life testing, and irradiation studie
ABSCHÄTZUNG DER GESAMTPROJEKTKOSTEN IM HOCHBAU
U radu se polazi od činjenice da je procjena ukupnih troškova projekata jedna od glavnih karakteristika
novih načina ustupanja radova u objektima visokogradnje. Opisana je koncepcija ukupnih troškova
projekata. Prikazani su postojeći klasifikacijski sustavi koji se najčešće primjenjuju u graditeljstvu, te
razvoj novog, konzistentnog i flexibilnog okvira za strukturiranje podataka koji će služiti za procjenu i
kontrolu ukupnih troškova projekata visokogradnje.The paper starts by emphasizing that the analysis of overall project costs is one of major features of
modern-day procurement of work in the sphere of building construction. The overall project cost
concept is described. Major classification systems currently used in construction industry are
presented, and the emphasis is placed on the development of new, consistent and flexible framework for
structuring data that will be used for the analysis and control of whole life costs (overall project costs)
for the building industy.L’article part du fait que l’évaluation des coûts globaux des projets est l’un des traits principaux des
nouvelles méthodes de l’adjudication des travaux dans le bâtiment. On décrit la conception des coûts
globaux des projets. On présente les systèmes de classification existants, utilisés le plus fréquemment
dans la construction, ainsi que le développement d’une nouvelle approche consistante et flexible de la
structuration des données qui serviront à l’évaluation et au contrôle des coûts globaux des projets dans
le bâtiment.В работе исходится из факта, что оценка общих расходов проектов является одной из главных
характеристик новых способов уступания работ в объектах высотного строительства.
Описана концепция общих расходов проектов. Показаны (представлены) существующие
классификационные системы, чаще всего применяемые в строительстве, а также развитие
нового, консистентного и флексибильного подхода для структуирования данных, которые
будут служить для оценки и контроля общих расходов проектов (на проекты, по проектам)
высотного строительства.Im Artikel geht man von der Tatsache aus dass die Abschätzung der Gesamtprojekt-kosten eines der
Hauptmerkmale neuer Arten der Leistungsvergabe für Objekte im Hochbau ist. Beschrieben ist die
Konzeption der Gesamtprojektkosten. Dargestellt sind die bestehenden Klassifizierungssysteme die am
meissten im Bauwesen angewendet werden, sowie die Entwicklung eines neuen, konsistenten und
flexibilen Rahmens für das Strukturieren der Daten die der Abschätzung und Kontrolle der
Gesamtkosten von Hochbauprojekten dienen werden
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