Monoploids in Zea mays L. occur spontaneously among individual diploid seedlings. Plants with the gametic chromosome number have also been detected among members of multiple seedlings of maize and numerous other species of angiosperms. Previous reports disclosed that Xirradiation of the pollen successfully stimulated reduced parthenogenesis in some other angiosperms, but the results of X-ray treatment were inconclusive in maize. Therefore, a tester stock of maize homozygous for lg land gl l was crossed with pollen from inbred CI3A, carrying the dominant alleles. The pollen was exposed to 0, 1000, 2000, and 4000r units of X rays. chromosome counts were made from root tips of plants exhibiting both recessive phenotypes to establish the frequencies of monoploids in the control and X1 populations.
Monoploids were more abundant among the individual seedlings from crosses with untreated pollen than in the X1 populations. X irradiation of the pollen is not a feasible method for the induction of monoploids in maize. The X-ray treatments greatly increased the frequency of multiple seedlings, and deficiencies were numerous among them. The members of a set of multiple seedlings were always genetically identical, and no monoploid members occurred. It is concluded that the induced deficiencies caused atypical development resulting in zygotic or embryonic cleavage.
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Scientific Article No. A2070, Contribution No. 5023 of the Maryland Agricultural Experiment Station, Department of Botany.
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Morgan, D.T. Monoploids in Zea mays L. following crosses with untreated and X-rayed pollen. Genetica 46, 133–138 (1976). https://doi.org/10.1007/BF00121029
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DOI: https://doi.org/10.1007/BF00121029