Studies on trisomics in a Jute hybrid

Autor: R. D. Iyer, P. K. Das
Rok vydání: 1972
Předmět:
Zdroj: Genetica. 43:473-488
ISSN: 1573-6857
0016-6707
DOI: 10.1007/bf00115593
Popis: Fifteen red pigmented trisomics were isolated in the F2 generation from the cross Corchorus olitorius L. x C. capsularis L. In the F3 generation a few green trisomics were obtained; more of these were isolated from the backcross generation. A detailed morphological and cytological analysis of the trisomic hybrid populations derived from the F3 and F4 generations is presented. The trisomics were scored for several morphologically differentiating characters and most of them were intermediate between the parental species, a few resembling the olitorius parent more. Cytological studies showed the formation of abnormal sporads in trisomics with different frequencies indicating a misdivision at meiosis. This imbalance at meiosis results in a higher percentage of pollen sterility in the trisomics as compared with the parents. Analysis of M1 of meiosis showed that there were: differences in the frequencies of the various chromosome configurations between the two categories of trisomics; significantly higher trivalent frequencies per PMC in the green trisomics; in contrast significantly hihger univalent frequencies per PMC in the red trisomics. No significant difference in chiasma formation was observed between red and green trisomics, nor between trisomics and their parental species. It appears that segmental homology in the parental chromosomes has probably resulted in varying degrees of preferential pairing in the trisomic hybrid.
Databáze: OpenAIRE
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