Question

Identity a,b and c in the table given below.

a. Pattern of inheritance	Monohybrid F1 phenotype
b. Codominance	Monohybrid F1 phenotype
c. Incomplete dominance	Progeny resembled only one of the parents

Answer 1

When two plants are crossed, new offspring generation plants are produced. This offspring generation is called the F1 generation or filial progeny. When 2 plants with different genotypes are cross-pollinated, the process is called hybridisation. Hybridisation studies are important in the study of inheritance and genetics. Usually when two plants with different characters are crossed any one character in one of the plants is expressed in the F1 generation.

Complete answer:

a. Pattern of inheritance	Progeny resembled only one of the parents
b. Codominance	Monohybrid F1 phenotype
c. Incomplete dominance	Monohybrid F1 phenotype

Inheritance is the process by which characters are passed on from parent to progeny. Inheritance is the basis of heredity, which is the innate tendency of an organism to imitate their parents. According to Mendel’s study on pea plants, when 2 plants with different traits of a character are crossed, the offspring express the character of any parent. The expressed trait of the character is called the dominant trait. This is called complete dominance. Exceptions to complete dominance are incomplete dominance, codominance etc.
When we are considering only the genes controlling one character it is called monohybrid. When two organisms which differ in only one character are crossed it is called a monohybrid cross. The phenotype of F1 progeny formed as a result of a monohybrid cross is called monohybrid F1 phenotype.
Always a dominant and recessive character doesn’t need to be present in an F2 generation. A phenomenon called Incomplete dominance is shown in some organisms wherein some F2 offspring both the traits of the plants get expressed which results in a state of transformation in the dominant character. Here the dominant character cannot completely dominate over a recessive character. For example, in snapdragon flower, when a crossing is done between true-breeding red flower and true-breeding white flower plants, all the F1 progeny formed have pink coloured flowers. Here monohybrid F1 phenotype shows incomplete dominance. When these F1 plants are self-pollinated to form F2 generation, red, pink and white-flowered plants are formed in 1:2:1 ratio.
Codominance occurs If a single character is controlled by more than two alleles of a gene. As humans are diploid organisms each person will cause any two of the alleles of the gene. If the two alleles present in an individual are dominant, both the alleles may be expressed. A good example is the ABO blood grouping in human beings where the gene controlling blood group, a gene I have three alleles. 2 are dominant alleles and one is a recessive allele. If both the parents have dominant alleles, the F1 monohybrid phenotypic will show characters of both the alleles. This is called a co-dominance.

Note: In complete dominance, the monohybrid F1 generation resembled the phenotype of either of the two parents and in incomplete dominance, the monohybrid F1 phenotype character was in between the parent phenotype characters. In codominance, the F1 generation can resemble both the parent characters in phenotype. Dominance is not an autonomous feature of a gene. It depends on the gene product and varies according to the phenotype under study. A phenotype may be influenced by more than one gene, called polygenic character.