The genetics and heritability of quantitative differences in N2 fixation in cowpea, Vigna unguiculata (L.) Walp /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1980.
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| Subjects: | |
| Online Access: | Link to ProQuest copy Link to OAKTrust copy |
| Abstract: | Cowpea, because of its ability to fix atmospheric nitrogen, coupled with its drought tolerance and ease of digestion, has become an important proteinaceous crop throughout the semi-arid regions of the world. Little research has been conducted on the genetics of N2 fixation in cowpea or in legumes, in general. Therefore, the purpose of this investigation was to study the genetics and determine the heritability of quantitative difference in the ability of cowpea genotypes to fix atmospheric nitrogen, with the ultimate goal of increasing vegetable protein in cowpea, by synthesizing superior N2 fixing genotypes. This research demonstrated that the genetics of N2 fixation in cowpea is controlled by several genes and that these genes are quantitatively inherited. Combining ability test indicated that specific combining ability was greater than general combining ability, using both Method 1 and 3, Model 1 of Griffin. These results indicated that it was the interaction of specific cowpea genotypes with the strains of rhizobia used, that was of primary importance in determining the amount of nitrogen fixed (C3H2 reduced), size of nodules and number of nodules produced. Broad sense heritability estimates were high, while narrow sense heritabilities were low. These results further reinforced the concept that the specific genotype x strains(s) interactions govern the trait of N2 fixation. Correlations between N2 fixation variables indicated that nodule mass was the primary determinant of C2H2 reduction, followed by nodule number and nodule specific activity. Dry weight of plant tops, however, was not correlated with C2H2 reduction, indicating that visual rating of plants by size in the field was not a reliable method of selection for enhance N2 fixation. |
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| Item Description: | "Major subject: Horticulture." Typescript (photocopy). Vita. |
| Physical Description: | xii, 116 leaves ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 109-115). |