Chromosome association in one induced and five natural tetraploids of sorghum

Reddi, Y.R. (1970) Chromosome association in one induced and five natural tetraploids of sorghum. Genetica , 41 (1). pp. 321-333.

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Abstract

A cytological analysis of chromosome association was made inS. miliaceum, S. panicoides, S. almum, S. macrochacta, S. halepense, and an induced autotetraploid ofS. cernuum all with2n=40 chromosomes. The study of pachytene chromosome associations in the first two species revealed their differentiated structure, while in the other species pachytene has not been analysed in detail. Also in their basic morphology they resembled diploid Eu-sorghums. The frequency of partner exchanges among the observed associations of four chromosomes varied from 0 to 2 and they appeared to be distributed all along the length of the chromosomes. Evidence for chromosomal differentiation was recorded and it was suggested that it might bring about increased bivalent synapsis when compared to the situation in the induced autotetraploid ofS. cernuum. Data also indicate thatS. miliaceum has essentially autoploid behaviour and thatS. panicoides is not closely related to any diploid Eu-sorghum. Comparison of the ehromosome behaviour in induced autotetraploidS. cernuum at post-pachytene stages of meiosis with that obtaining inS. almum andS. halepense suggests that the latter specios might have undergone considerable chromosomal differentiation at the same time retaining autoploid behaviour.S. macrochaeta on the other hand, has been classified segmental alloploid. Meiotic irregularities were present to a varying extent and it is considered that genetic factors are also important in determining the ultimate fertility of the tetraploids studied.

Item Type: Article
Author Affiliation: Andhra University
Subjects: Crop Improvement
Divisions: Sorghum
Depositing User: Mr. SanatKumar Behera
Date Deposited: 29 May 2012 06:17
Last Modified: 29 May 2012 06:17
Official URL: http://dx.doi.org/10.1007/BF00958915
URI: http://eprints.icrisat.ac.in/id/eprint/5879

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