Koduru, P.R.K. (1984) Centromere orientation, reorientation, and segregation in an interchange quadrivalent during anther development in pearl millet. Chromosoma, 90 (2). pp. 94-102.
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Abstract
Prometaphase I orientation, reorientation and anaphase I segregational behaviour of a chain-forming interchange quadrivalent involving one of the long chromosomes and the long arm of the seventh (nucleolar) chromosome was studied during anther development in Pennisetum americanum. Data obtained from 34 anthers showed that by early prometaphase I about 90% of the bivalents have attained stable bipolar orientation but about 48% of the quadrivalents are badly orientated. There seems to be an interaction between bivalents and quadrivalents during bad orientation and reorientation. The badly orientated bivalents reorientated before the quadrivalents. For bad orientation of quadrivalents four types, 4/0, 3/1, 2/1/1 and 2/2 (adjacent 1), were distinguished in addition to the "regular" types, adjacent 2 and alternate. Based on their potential to reorientate, the order of the badly orientated quadrivalent types was 4/0 > 3/1 > 2/1/1; 2/2 led to anaphase I disjunction, as for an adjacent 1 segregation. Data from 36 anthers at anaphase I showed alternate segregation of chromosomes in nearly 50% of PMCs up to a developmental index of about 65. In late anthers about 35% of PMCs showed alternate segregation. It is suggested that the PMCs that reached metaphase I later had more adjacent 2 orientations since badly orientated configurations delay meiotic development, and it is implied that preferential reorientation behaviour of the badly orientated quadrivalent types occurs
| Item Type: | Article |
|---|---|
| Author Affiliation: | Department of Botany, Andhra University, Waltair 530 003, India |
| Subjects: | Crop Improvement > Genetics/Genomics Crop Improvement > Plant Breeding |
| Divisions: | Millet Other Crops |
| Depositing User: | Ms K Syamalamba |
| Date Deposited: | 30 May 2012 10:53 |
| Last Modified: | 30 May 2012 10:53 |
| Official URL: | http://dx.doi.org/10.1007/BF00292445 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/5964 |
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