Jauhar, P.P (1970) Chromosome behaviour and fertility of the raw and evolved synthetic tetraploids of pearl millet,Pennisetum typhoides stapf et hubb. Genetics, 41 (1). pp. 408-424.
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Abstract
The effect of colchicine-induced chromosome doubling on phenotypic characters of Pearl millet,Pennisetum typhoides, is described and the mutagenic effect of colchicine preliminarily indicated. Meiosis in the raw tetraploids was characterized by a high frequency of multivalents, mostly quadrivalents. The evolutionary implication of the occurrence of multivalents higher than quadrivalents is discussed. When the synthetic autototraploids were carried through C6, a shift from a multivalent to a bivalent type of association was noticed, and some of the quadrivalents formed in the C5 and C6 generations appeared to be loosely associated. It is suggested that structural divergence of the chromosomes combined with genetic factors may jointly be the cause. Evolutionary and breeding consequences are discussed. With the acquisition of a predominantly bivalent type of meiotic association, seed setting in the tetraploids improved. The relative roles of meiotic abnormalities and genetic factors in bringing about seed sterility in the tetraploids are considered. Cytological instability resulted in aneuploids and diploids in the progeny. Factors which may predispose a tetraploid taxon to cytological instability are discussed. It has been suggested that the secondarily diploid nature of Pearl millet may contribute to the cytological instability of its tetraploids. Preliminary observations on three trisomics and one monosomic, isolated in this study for the first time, are recorded. It was interesting to note that a monosomic plant of Pearl millet could survive up to maturity. This observation would further suggest that Pearl millet is not a true diploid but a secondarily balanced species with its phyletically basic number less thanx=7, as earlier inferred by the author from several evidences published elsewhere
| Item Type: | Article |
|---|---|
| Author Affiliation: | Division of Genetics, Indian Agricultural Research Institute, New Delhi-12, India. |
| Subjects: | Crop Improvement |
| Divisions: | Millet |
| Depositing User: | Library ICRISAT-InfoSAT |
| Date Deposited: | 04 Mar 2012 09:39 |
| Last Modified: | 04 Mar 2012 09:39 |
| Official URL: | http://dx.doi.org/10.1007/BF00958922 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/3432 |
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