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71.
Summary A simple and effective selection procedure for identifying lines with wide adaptation and ability to do well under drought is outlined, supported with experimental data involving diverse and high yielding populations of bread wheat.The effect of selections for local adaptation to stress environment is found to be inferior as compared to selection for developmental traits in a favourable environment. Data on selection for developmental traits have shown favourable correlated associations with more precision in the estimate of components of genetic variation and heritability and larger magnitude of response to selection as compared to selection for yield components in stress environment.The developmental characters such as early vigour and synchronous tillering, days to heading and ear length which show stability over different environments are found to be important components of wide adaptation and productivity under moisture-stress.Presented at the Symposium on Planning for the Drought of the National Institute of Sciences, held in New Delhi, India, 4–6 May, 1969. 相似文献
72.
73.
D. Roy Davies 《Euphytica》1976,25(1):717-724
Summary A cellulose acetate electrophoretic technique has been used to characterise the storage proteins present in pea seeds in order to try and determine the proportions of proteins present which are enriched in sulphur amino-acids. Some of the eight varieties examined were shown to differ in their proportions of the various storage proteins. When the proteins were separated and estimated quantitatively and also characterised by their sub-unit composition, it was shown that cellulose acetate electrophoresis of crude protein extracts or of whole globulins did not give the degree of resolution required. The procedures which have to be undertaken in order to obtain this information are considered, and the difficulties of incorporating them into a plant breeding programme discussed. 相似文献
74.
Inheritance of fiber quality and lint yield in a chemically mutated population of cotton 总被引:2,自引:0,他引:2
Andy D. Herring Dick L. Auld M. Dean Ethridge Eric F. Hequet E. Bechere Cary J. Green Roy G. Cantrell 《Euphytica》2004,136(3):333-339
The narrow germplasm base of the upland cotton (Gossypium hirsutum L.), grown on the Texas high plains historically, has limited improvement of fiber quality. Chemical mutagenesis and subsequent selection have helped the development of lines with improved fiber quality in cultivars adapted to this region. This study was conducted to determine the inheritance of improvements in fiber quality. M3 lines with divergent fiber properties of micronaire, length, and strength were selected from a population of Paymaster HS 200 treated with 3% v/v ethyl methanesulfonate (EMS) for two hours. The 115 selected lines of M4 and M5 generation were evaluated for fiber quality and lint yield. Regression of the M4 and M5 on the M3 generation, as well as the M5 on the M4 was used to generate narrow sense heritability coefficients. Significant variations were observed between the mutant lines in all generations except for lint yield in the M5 (1997). The highest heritability estimates were found in fiber length (h
2= 0.29** to 0.46**). Micronaire and strength showed intermediate heritability estimates of h
2= 0.14 to 0.19, while lint yield had a very low heritability estimate of h
2= 0.03. Fiber length and strength were correlated (r= 0.58** to 0.46**) in all the three generations. The mutants identified in these studies have the potential to improve fiber quality of upland cotton without introducing alien genes that may reduce adaptation to short growing season production regions. 相似文献
75.
Coleen L. Moloney John Cooper Peter G. Ryan W. Roy Siegfried 《Biological conservation》1994,70(3):195-203
An age-structured model of a wandering albatross Diomedea exulans population is developed to stimulate population trends over time, using demographic parameters from the population at Possession Island, Crozets, during 1968–1986. The simulation results portray a population decreasing at a rate of 2·29% per year, which concurs with global population trends. Sensitivity analyses of model parameters indicate that both adult and juvenile mortality are contributing to the decrease. Wandering albatross mortality is presumed to have increased as a result of deaths caused by longline fishing vessels; such deaths are likely to be relatively more frequent among young, naive birds. The model is used to investigate the potential impacts of new longline fisheries such as that for Patagonian toothfish Dissostichus eleginoides in Antarctica. Assuming longline fishing operations affect juveniles more than adults, there is a time lag of 5–10 years before further decreases in population numbers are reflected in the breeding population. Also, because wandering albatrosses are long-lived, population growth rates take approximately 30–50 years to stabilize after a perturbation. Consequently, caution must be exercised when interpreting population trends; short-term (<20 year) estimates may not provide good indications of long-term trends. 相似文献
76.
Hazards of Ag from weather modification to micro-organisms of the rumen were evaluated in vitro and in vivo. Silver iodide complexes at a concentration of 38 ppm of Ag in dry alfalfa substrate did not affect substrate digestion in vitro. Inhibition of rumen microbial digestion was noted with 100 or more ppm of Ag, as Ag NO3, in an in vitro fermentation system. A chronic intake of 1 ppm of Ag in dry-matter intake did not produce gradual accumulation of Ag in the rumens of two goats. Silver passed from a goat rumen with a half time of 1.3 days. In two in vivo trials, neither suspensions of AgI complexes simulating 1 ppm of Ag in dry food intake nor solutions of AgNO3 simulating 100 ppm of Ag in dry food intake inhibited rumen digestion rates. An abundance of chloride ions, proteins, bacteria and other organic matter precludes persistence of Ag ions in the rumen. Based on these results, Ag in forages in areas where clouds are seeded with AgI complexes, including areas near AgI generators, where forages rarely contain more than 1 ppm of Ag in dry matter, will not affect rumen microbial digestion. 相似文献
77.
Md. Habibur Rahman Md. Abu Sayed Arfin Khan Bishwajit Roy Most. Jannatul Fardusi 《林业研究》2011,22(4):551-559
A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (a part of Sylhet Forest Division)
to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic
species. Data were collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots
of 2 m×2 m in size had 5 different habitat types of plants namely; forest, roadside, homestead (surrounding forest dwellers
house), fallow land and others (canals, streams and tea gardens side), which included a total of 55 regenerating species belonging
to 28 families. Meliaceae is the dominant family and shows the highest family importance value (26.3), having six species,
followed by Moraceae (24.24). Among the five habitat types, forest (43 species) possess the highest number of species, followed
by roadside (23 species). Total 15 exotic species among 9 families and 40 indigenous species with 24 families were recorded.
For exotic species, Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%). In case of indigenous species, Chickrassia tabularis possess the highest relative density (4.23%) and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia tabularis (10.8) had the highest IVI for exotic and indigenous species respectively. Different diversity indices such as Shanon-Winner
diversity index, species diversity index, species richness index, species evenness index, Simpson index and species dominance
index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levels of disturbance
was in the exotic species. Study suggests that proper protection from human disturbances and scientific management of natural
regeneration of two-study forests may lead a rich biodiversity site in the country. 相似文献
78.
Franck Richard Melanie Roy Oula Shahin Christopher Sthultz Myriam Duchemin Richard Joffre Marc-André Selosse 《Annals of Forest Science》2011,68(1):57-68
• Introduction
Millions of hectares of Quercus ilex forests dominate disturbed landscapes in the western part of the Mediterranean basin. Although these forests are very widespread, little is known about the composition and structure of their associated ectomycorrhizal fungal communities. 相似文献79.
80.
Airan RD Meltzer LA Roy M Gong Y Chen H Deisseroth K 《Science (New York, N.Y.)》2007,317(5839):819-823
The hippocampus is one of several brain areas thought to play a central role in affective behaviors, but the underlying local network dynamics are not understood. We used quantitative voltage-sensitive dye imaging to probe hippocampal dynamics with millisecond resolution in brain slices after bidirectional modulation of affective state in rat models of depression. We found that a simple measure of real-time activity-stimulus-evoked percolation of activity through the dentate gyrus relative to the hippocampal output subfield-accounted for induced changes in animal behavior independent of the underlying mechanism of action of the treatments. Our results define a circuit-level neurophysiological endophenotype for affective behavior and suggest an approach to understanding circuit-level substrates underlying psychiatric disease symptoms. 相似文献