Cytomixis in Pollen Mother Cells of Citrus Genotypes

摘要

A microsporogenesis analysis performed in several Citrus populations revealed the presence of cytomixis (i.e., chromatin migration between meiocytes) in pollen mother cells of diploid and tetraploid genotypes. Single and double chromatin bridges between adjacent meiocytes were mainly observed at prophase I, but also in the subsequent phases of first division and in the second meiotic division. The percentage of cytomictic cells in the genotypes examined was quite variable. In addition to cytomixis, other meiotic abnormalities were observed, in both the first and second meiotic divisions. The cytomictic plants showed lower values of pollen viability compared to the control plants. A possible relationship between the occurrence of cytomixis, pollen viability and the reduced fertility of Citrus populations is discussed.