Dimensions of diversity in CIMMYT bread wheat from 1965 to 2000
Since a well-meaning scientific community first raised public concern several decades ago, the spread of modern varieties has been viewed as the impetus for a narrowing in the erop genetic diversity that is necessary to ensure adequate food production in a rapidly changing world. This paper tests the hypothesis of narrowing genetic diversity in CIMMYT related spring bread wheats and summarizes scientific evidence for varieties grown in the developing world from 1965 to the present. Data sources include both previously published studies and analyses of new experimental, molecular, and socioeconomic data. In 2000, though an estimated 90% of the scientifically bred wheats grown in the developing world (excluding China) are CIMMYT related, they are not uniform. CIMMYT-related varieties are a vast array of germplasm constituted by genetic recombination of diverse sources of materials from throughout the wheat-growing world. On a global scale, point estimates over time suggest that the dominance of major varieties has declined, and more varieties have been made available and are being grown by farmers. There is no evidence that more popular varieties are more related in ancestry than minor varieties. The hypothesis of genetic narrowing is tested by assessing changes in the diversity of leading CIMMYT progenitors over three decades, in terms of latent (unobservable) and apparent (observable) "dimensions" or aspects of diversity. Latent dimensions include genetic distance and genealogies
| Main Authors: | , , , , , , , , |
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| Format: | biblioteca |
| Published: |
México, DF (México)
2001
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| Subjects: | TRITICUM AESTIVUM, FITOMEJORAMIENTO, VARIACION GENETICA, RESISTENCIA A LA ENFERMEDAD, RESISTENCIA A LA TEMPERATURA, RENDIMIENTO DE CULTIVOS, ADOPCION DE INNOVACIONES, PAISES EN DESARROLLO, |
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| Summary: | Since a well-meaning scientific community first raised public concern several decades ago, the spread of modern varieties has been viewed as the impetus for a narrowing in the erop genetic diversity that is necessary to ensure adequate food production in a rapidly changing world. This paper tests the hypothesis of narrowing genetic diversity in CIMMYT related spring bread wheats and summarizes scientific evidence for varieties grown in the developing world from 1965 to the present. Data sources include both previously published studies and analyses of new experimental, molecular, and socioeconomic data. In 2000, though an estimated 90% of the scientifically bred wheats grown in the developing world (excluding China) are CIMMYT related, they are not uniform. CIMMYT-related varieties are a vast array of germplasm constituted by genetic recombination of diverse sources of materials from throughout the wheat-growing world. On a global scale, point estimates over time suggest that the dominance of major varieties has declined, and more varieties have been made available and are being grown by farmers. There is no evidence that more popular varieties are more related in ancestry than minor varieties. The hypothesis of genetic narrowing is tested by assessing changes in the diversity of leading CIMMYT progenitors over three decades, in terms of latent (unobservable) and apparent (observable) "dimensions" or aspects of diversity. Latent dimensions include genetic distance and genealogies |
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