Cytogenetics, Breeding Behavior and Tumor Formation in Progeny of a Homozygous Triploid Sorgham

Univalents were studied in the microsporocytes of a triploid sorghum plant which was derived from a selfed haploid. At metaphase I, the frequencies of univalent varied with cell maturity which was judged by anther development. The developmental stages of anthers were E, M, L, VL, and VVL for early, medium, late, very late, and very, very late respectively. Univalents averaged 2.3 per cell at the earliest (E) stage increased to 3.9 per cell at the latest (VVL) stage. A similar tendency was found from L to VVL at anaphase I and telophase I. Trivalents were also studied in cell populations used for study of univalents. The types of trivalent identified were linear, convergent and indifferent. No relationship was found between the occurrence of linear type trivalents and anther development. The frequency of convergent type trivalents was stable through five stages of anther development. However, indifferent type trivalents tended to decrease apparently in association with the increase in univalent. Averages of 2.3 linear type trivalents, 3.9 convergent type trivalents and 1.0 indifferent type trivalents per cell were found. (see more in text