SPONTANEOUS ANEUPLOIDS OF MAIZE (ZEA MAYS) IN A SELECTED SAMPLE

Abstract

A maize (Zea mays L.) sample with a high frequency of spontaneous aneuploids was prepared by selecting seeds and plants. The study was carried out on seeds discarded during the mechanical processing of a commercial hybrid. Starting from a discarded bulk of 20,000, a selected fraction of about 4,000 small and malformed kernels was planted in the field. Further selection was made by examining the developing plants and their pollen. A group of 46 plants was selected because of relatively high pollen sterility or abnormal plant growth and subjected to genetic investigation. After crossing these plants to inbred lines, 14 of them (about 30%) produced aneuploids among the offspring; a few of these aneuploids were cytologically identified as primary trisomics. The high pollen sterility was not associated with the aneuploid condition. This finding suggests that selection was made for structurally altered chromosomes whose behavior during the meiotic process gave rise to aneuploids.