Dihybrids

A dihybrid cross is the crossing of two pure lines of organisms that differ in two or more traits. Dihybrid crosses result in offspring that have different combinations of the inherited characteristics of their parents.

The purpose of dihybrid hybridization is to identify individual traits and characteristics that are inherited in combination and to find out how they are related to each other. This is of great importance for understanding the processes of heredity and their use in the breeding of crops and animals to increase productivity and improve the quality of products. Dihybrid analysis crosses include crossing all possible pairs of two pure lines. The result will be a tetrad of groups consisting of four varieties. In each group there is uniformity in one pair and variability in the other. It can be noted that each group has five individuals, two phenotypically pure lines, one hemic pure line, or an intermediate phenotype.

In a dihybrid test cross, the pure lines that are usually bred are called the recessive line. With such crossing, the original pure lines replace their genes in places in the gametes in full accordance with Mendel's rule. For each pair of alleles considered in a given phenotype, the 1 by 2 and three by four rules apply. For example, a homozygous purebred cocconitropsis bush will transfer its two dominant genes through F2 - 1 - yellow cocconitropy, 1 - green. Then, three recessive genes are exchanged through - F3 - with a recessive character, a yellow variety is obtained, and with a dominant character, a green variety is obtained. To calculate a godson, fifty offspring should be obtained, subject to the presence of gametes in each individual. The number of plants is reduced to one. Dihybrid hybridization is a classic example of the inheritance of traits in the genetic analysis of allelic forms of various genes.