Triploidy induced by gamma irradiation during meiosis in sunflower

Abstract

1. Under effect of a large dose (20 Kr) of gamma irradiation performed during the microsporogenesis of sunflower the formation of tetrads is affected by ray injury which not unfrequently results in production of triads. 2. Also a nucleus with diploid chromosome number takes place among the triads. Under the first and second maturity divisions a synchronous divergence can be demonstrated which becomes only stronger towards the final phase of microsporogenesis. 3. As a result of fecundation caused by diploid pollen a possibility exists also for the production of triploid progenies. According to examinations the number of triploid progenies (3n=51) varies at about 4 per cent. 4. In a large part of progenies with triploid chromosome number the chromosomes are thinned and weakly stainable which may be regarded as a symptom of ray-injury. Under effect of a large dose (20 Kr) of gamma irradiation performed during the microsporogenesis of sunflower the formation of tetrads is affected by ray injury which not unfrequently results in production of triads. Also a nucleus with diploid chromosome number takes place among the triads. Under the first and second maturity divisions a synchronous divergence can be demonstrated which becomes only stronger towards the final phase of microsporogenesis. As a result of fecundation caused by diploid pollen a possibility exists also for the production of triploid progenies. According to examinations the number of triploid progenies (3n=51) varies at about 4 per cent. In a large part of progenies with triploid chromosome number the chromosomes are thinned and weakly stainable which may be regarded as a symptom of ray-injury. Als Folge einer starken Gamma-Bestrahlung (20 Kr) während der Mikrosporogenese der Sonnenblume zeigten sich Strahlenschädigungen bei der Tetradenbildung, es ergaben sich nicht selten Triaden. Unter ihnen wurde auch ein Nukleus mit diploider Chromosomenzahl beobachtet. Bei der 1. und 2. Reifeteilung konnte eine synchrone Divergenz nachgewiesen werden, die gegen Ende der Mikrosporogenese stärker wurde. Eine Möglichkeit für das Auftreten triploider Nachkommenschaften kann auch in der Befruchtung durch diploiden Pollen gesehen werden. Bei unseren Untersuchungen schwankte die Zahl der triploiden Nachkommenschaften (3n=51) um 4%. Bei einem großen Teil der Nachkommenschaften mit triploider Chromosomenzahl sind die Chromosomen dünn und schlecht färbbar, was als Symptom einer Strahlenschädigung angesehen werden kann.

DOI: 10.1007/BF00712133

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Cite this paper

@article{Pozsr2004TriploidyIB, title={Triploidy induced by gamma irradiation during meiosis in sunflower}, author={B. I. Pozs{\'a}r and E. Kurnik and J. Parragh}, journal={Der Z{\"{u}chter}, year={2004}, volume={33}, pages={65-68} }