“…A number of reports of spontaneous chromosome breakage are now on record for various plant genera including Tradescantia (Giles, 1940;Darlington and Upcott, 1941), Hyacinthus, Tulipa (Darlington and Upcott, 1941), Paris (Haga, 1953), Paeonia (]. L. Walters, 1956), and in hybrids between Allium cepa and A. fistulosum (Emsweller and Jones, 1938). In all instances, save Paeonia, a high level of chromosome breakage was found to be correlated with a visible repatterning of the chromosomes, as observed in pollen mitoses, and in the case of the Allium hybrid, more or less fertile lines with altered chromosome arrangements were obtained by selection from among the progeny of the Fl.…”