Chromosome Elimination in Intergeneric Hybrid of <i>Oryza sativa</i> × <i>Luziola peruviana</i>

Abstract

Oryza sativa and Luziola peruviana present a diploid chromosome number of 2n = 24 and basic number x = 12, confirmed by means metaphase chromosomes counts in young root tips of these species. Hybrid plants O. sativa × L. peruviana, with 2n = 24 chromosomes are originated from simple crosses and present abnormalities in the meiotic behavior, chromosomal aberrations and cytological alteration. This genetic incompatibility is caused by different factors as absence of pairing and recombination, different spindles arrangements, cytoskeleton instability, apoptosis process and chromosomal elimination, leading to micronuclei formation, unbalanced gametes and sterile pollen grains. The chromosome elimination is established as a dynamic process of stabilization of the genome that occurs during hybridization. It is a common phenomenon among intergeneric crosses and corresponds to cytoplasmic and nuclear bodies that reflect chromosomal aberrations resulting from the combination of two genomes with high genetic distance. The genomic conflict occurs in meiosis, possibly by asynchronism and cell cycle length of the genomes involved, or by time differences in replication between parental species leading to strand breaks and genomic rearrangements.