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61.
Summary A partial male sterility system in the soybean (Glycine max (L.) Merr.) germplasm population AP6(SI)CI was found to be controlled monogenically by a recessive allele, msp. Observations of msp msp plants in different environments suggested that environmental conditions significantly affect expressivity of the msp allele with respect to male sterility. We obtained no experimental evidence of cytoplasmic effects on msp expression. Background genotypes, however, seem to affect msp expressivity through their determination of flowering dates and resultant interactions with varying environmental conditions.Homogeneous populations of partially male-sterile plants can be generated by increasing families of msp msp plants in fertility-inducing environments, if measures are implemented to prevent the introduction and/or build-up of fertile genotypes that arise from natural cross-pollinations.Joint contribution: North Central Region, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, and Journal Paper No. J-9596 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa 50011; Project 2107. 相似文献
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Effects of charcoal production on maize yield,chemical properties and texture of soil 总被引:4,自引:0,他引:4
Philip?G.?OguntundeEmail author Matthias?Fosu Ayodele?E.?Ajayi Nick?van de?Giesen 《Biology and Fertility of Soils》2004,39(4):295-299
The effects of charcoal production on soil textural and chemical properties were investigated in Ejura, Ghana. The aim was to study the effects of heating and charcoal residue on maize yield, soil texture and soil chemical properties. Composite samples were taken from the 0–10 cm layer of soil at charcoal-making sites and from adjacent fields (control). Twelve sites were randomly selected for the study across the range of the Kotokosu watershed. Maize was planted in four selected locations on charcoal site soils (CSS) and adjacent field soils (AFS) to assess the impact of charcoal production on crop yield. There was a significant increase in soil pH, base saturation, electrical conductivity, exchangeable Ca, Mg, K, Na and available P in the soil at the kiln sites as compared to the adjacent soils. A relative change of up to 329% was observed in K while organic C and total N decreased by 9.8% and 12.8%, respectively. Organic C and total N were highly correlated ( P <0.01) and both parameters significantly ( P <0.05) depended on clay minerals in the soils. Soil texture was also modified with a significantly higher sand content and lower clay fraction in the CSS. The grain and biomass yield of maize increased by 91% and 44%, respectively, on CSS as compared to AFS. Further research to ascertain the long-term effects of charcoal production on the soil environment and the fertility of tropical soils is needed. 相似文献
64.
Reid IN 《Science (New York, N.Y.)》2002,296(5576):2154-2155
65.
Protein-DNA interactions in vivo upstream of a cell cycle-regulated human H4 histone gene 总被引:23,自引:0,他引:23
Cell cycle-dependent histone genes are transcribed at a basal level throughout the cell cycle, with a three- to fivefold increase during early S phase. Protein-DNA interactions in the 5' promoter region of a cell cycle-regulated human H4 histone gene have been analyzed at single-nucleotide resolution in vivo. This region contains two sites, with four potential protein-binding domains, at which the DNA is protected from reaction with dimethyl sulfate in cells and from digestion with deoxyribonuclease I in nuclei. These protein-DNA interactions persist during all phases of the cell cycle and dissociate with 0.16 to 0.2M sodium chloride. 相似文献
66.
Gage KS McAfee JR Carter DA Ecklund WL Riddle AC Reid GC Balsley BB 《Science (New York, N.Y.)》1991,254(5039):1771-1773
Measurement from Christmas Island (2 degrees N, 157 degrees W) of long-term mean vertical motions in the tropical atmosphere using very-high-frequency wind-profiling Doppler radar show that there is a transition from downward motion in the free troposphere to upward motion in the upper troposphere and lower stratosphere. The observations in the free troposphere are consistent with a balance between adiabatic and diabatic heating and cooling rates in a clear atmosphere. Comparison of the results at Christmas Island during El Ni?o and non-El Ni?o conditions with earlier results obtained for stratiform rain conditions over Pohnpei, Federated States of Micronesia, show that cirrus clouds in the vicinity of the tropopause likely play an important role in determining the sense and magnitude of vertical motions in this region. These results have implications for the exchange of mass between the troposphere and stratosphere over the tropics. 相似文献
67.
Genetically determined sex-reversal in 46,XY humans 总被引:6,自引:0,他引:6
J German J L Simpson R S Chaganti R L Summitt L B Reid I R Merkatz 《Science (New York, N.Y.)》1978,202(4363):53-56
Evidence is presented for the existence of a gene, probably on the X chromosome, which prevents testis differentiation when present in 46,XY human embryos. Affected 46,XY women are not completely normal because of premature ovarian involution, as a result of which they have "streak gonads" similiar to those of 45,X women. 相似文献
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