In 1978, Ting et al. (Acta Genetica Sinica) reported that H2 plants (2nd generation of pollen plants) from the intercrossing of sister dihaploid pollen plants consistently showed chromosome stickiness during the first meiotic divisions of the microsporocytes in the maize strain Lai-Bin-Bai. On the other hand, in the H2 plants from the selfing of pollen plants of maize strain Gui-Dan-12, meiotic chromosome behavior in the microsporocytes appeared normal in the first division. In 1985, Ting (Maydica) again studied chromosome behavior in pollen plants of the maize strain Dan-San-91. In the first meiotic divisions of the microsporocytes of haploids, aneuploids and dihaploids of the H1 generation, chromosome fusions (stickiness) were always present. In view of the above inconsistent observations it was deemed necessary to make a further study on the meiotic chromosome behavior of maize pollen plants and their progenies.
In the summer of 1986, microsporocytes of three plants each of the H1 and H2 progenies of pollen plants of maize Dan-San-91 were collected and fixed according to the standard aceto-carmine squash technique. Upon microscopic examination it was found that, at the first meiotic prophase, chromosome fusions persisted from early leptotene-zygotene stage to metaphase I. Laggards at anaphase I and II were also observed, but the percent of cells having this kind of irregularity was very small. Both of the above appeared in all the plants studied. Nevertheless, the other aspects of meiotic chromosome behavior appeared normal. Regarding fertility, all of the plants had practically full seedsets.
Y.C. Ting and Stephen Schneider
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