Cytomixis: Causes and consequences as a case study in Vicia faba L.

Abstract

Broad bean (Vicia faba L.) is a member of the family Fabaceae which showed cytomixis during microsporogenesis. Cytomixis is proposed to be caused by genes, abnormal cell wall formation, action of chemicals, changes in the biochemical process, imbalanced and sterile genetic systems, persistence of male-sterile mutant genes, and frequent alterations in environmental factors. The cytomixis was found to happen through different methods, i.e., cytoplasmic channels and direct fusion method in the meiocytes. The former was more abundant than the latter, and both the methods were found in various phases of microsporogenesis. The transfer of chromatin material involved the whole diploid set of chromosomes or some chromosomes in the diploid set from donor to recipient cell/cells. The PMCs which showed deviation from the basic diploid chromosome number by cytomixis may lead to the formation of aneuploid and polyploid gametes. Stickiness was found in all the mutagen-treated population and showed dose-dependent increase with the mutagens. There was found positive correlation between the pollen fertility, cytomixis, and chromosomal stickiness. Genetic factors might have been also contributed toward decrease in pollen fertility. The cytomixis was reported in both the varieties of Vicia faba L., but the var. minor showed more frequency than var. major along with stickiness and reduction in pollen fertility indicating its greater sensitivity to the mutagens.