Principles of Inheritance & Variation Test 3

Emasculation is the process of removal of anthers. This is carried out to carry out pollination in a controlled manner and avoid self-pollination.

Self-pollination leads to fertilization by the pollen from the same flower. A cross desires pollination and fertilization by pollen from a different plant. Hence self-pollination needs to be avoided.

True-breeding plants are taken as parental plants in crosses. Hence offsprings produced by the crossing of these true-breeding plants are F1 progeny.

F1 progeny refers to the first generation of offsprings. This is also termed as the first Filial generation, thereby stating their filial relationship with the true-breeding plants.

Tall plants are dominant over dwarf plants. Being true-breeding parents, the offsprings will all be heterozygous. Moreover, hence phenotypically, all of them will be tall.

Inflated is the dominant phenotype. Hence it can be expressed in two genotypes: II and Ii. The F1 progeny can have it in all the mentioned cases except when both parents are recessive ii.

Violet is the dominant factor over white in pea flowers. Hence violet can express even in the presence of white. The cross of violet true-breeding and white true-breeding pea plants will produce all heterozygous offsprings. Thus, all of them will have violet flowers.

Yellow being recessive will express only when both alleles are present. That occurs only when both parents can contribute an allele encoding for the yellow pod. For all progeny to have yellow pods, both parents have to be homozygous for yellow pods.

The VV and vv upon crossing will produce all progeny with genotype Vv. This is the heterozygous state. Violet being dominant over white, all the progeny will have violet flowers.

A dominant factor masks the expression of its recessive counterpart. Thus, it can express in both homozygous and heterozygous states.

Monohybrid refers to a hybrid that differs at only one gene. Thus, a plant that exhibits two alleles for one trait is a monohybrid.

Based on his studies on pea plants, he observed that the parental recessive traits were observed again only in the F2 progeny without any form of blending in F1 generation. This points out that the factors segregate or separate during the process of meiosis.

Heterozygosity refers to different alleles present at a given locus. This is the condition that is of interest to the study of genetics. It can be used to test the nature of an allele.

Violet is dominant over white. Self-crossing of violet flowered plants will produce 25% recessive plants, which will have white-flowers.

The F2 progeny has both dwarf and tall plants. 25% of them are homozygous tall, 50% are heterozygous tall, and 25% are homozygous dwarf. Dwarfness is a recessive trait and thus cannot be expressed in the heterozygous state.