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  • 1
    Electronic Resource
    Electronic Resource
    The area under the function: an index for selecting desirable genotypes (1993)
    Springer
    Theoretical and applied genetics 87 (1993), S. 409-415 
    Details
    ISSN: 1432-2242
    Keywords: Genotype x environment interaction ; Adaptation ; Stability ; Desirability index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The linear regression approach has been widely used for selecting high-yielding and stable genotypes targeted to several environments. The genotype mean yield and the regression coefficient of a genotype's performance on an index of environmental productivity are the two main stability parameters. Using both can often complicate the breeder's decision when comparing high-yielding, less-stable genotypes with low-yielding, stable genotypes. This study proposes to combine the mean yield and regression coefficient into a unified desirability index (D i). Thus, D i is defined as the area under the linear regression function divided by the difference between the two extreme environmental indexes. D i is equal to the mean of the i th genotype across all environments plus its slope multiplied by the mean of the environmental indexes of the two extreme environments (symmetry). Desirable genotypes are those with a large D i. For symmetric trials the desirability index depends largely on the mean yield of the genotype and for asymmetric trials the slope has an important influence on the desirability index. The use of D i was illustrated by a 20-environments maize yield trial and a 25-environments wheat yield trial. Three maize genotypes out of nine showed values of D i 's that were significantly larger than a hypothetical, stable genotype. These were considered desirable, even though two of them had slopes significantly greater than 1.0. The results obtained from ranking wheat genotypes on mean yield differ from a ranking based on D i .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215085
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  • 2
    Electronic Resource
    Electronic Resource
    Colitis and Colon Cancer in Cotton-Top Tamarins (Saguinus oedipus oedipus ) Living Wild in Their Natural Habitat (1998)
    Springer
    Digestive diseases and sciences 43 (1998), S. 1443-1453 
    Details
    ISSN: 1573-2568
    Keywords: COLITIS ; INFLAMMATION ; INFLAMMATORY BOWEL DISEASE ; COLON CANCER ; COLORECTAL CANCER ; NONHUMAN PRIMATE ; COTTON-TOP TAMARIN
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The cotton-top tamarin is a nonhuman primate noted for susceptibility to juvenile onset colitis and subsequent colon cancer. About 80% develop colitis in captive environments outside the tropics. The aim was to determine the prevalence of colitis and colorectal cancer in tamarins living wild in their tropical habitat. Endoscopic biopsy was used to compare severity of colitis, inflammatory/immune cell densities, mucosal dysplasia, and occurrence of cancer in wild tamarins in a tropical habitat with tamarins living captive in a temperate climate. Six colon biopsies from each of 69 captives showed severe colitis in 64.5% of biopsies and moderate colitis in 19.5% . Severe colitis was not found in 88 wild tamarins; 13% had moderate colitis. Densities of polymorphonuclear leukocytes, plasma cells, and mononuclear cells in the lamina propria were related directly to the severity of four grades of colitis (normal, mild, moderate, and severe). Histologic or gross signs of carcinoma were detected in 12 captives and low- or high-grade dysplasia in 15. Neither cancer nor dysplasia was found in any of the wild tamarins. The observations suggest that colitis and cancer in the tamarin model are linked to environmental factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018842210330
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    Paper (German National Licenses)
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