In normal conditions, the phenotype of the progeny depends on the genes present in the nucleus and is called as chromosomal inheritance, where there is a simple association between the genes located on the chromosomes and observed phenotypes in the progeny. The male gametes and female gametes equally contribute to the phenotype of progeny and there is no differences observed with phenotypes with reciprocal crosses. In some exceptional cases, the phenotype is not dependent on the nuclear genes and is controlled by the genetic content present in the cytoplasm