Genetics And Plant Breeding MCQ Question and Answer | Agriculture MCQ Question

Pure line selection is mainly done for Self-pollinated crops.
Pure-line selection involves selecting and breeding progeny from superior organisms for several generations until a pure line of organisms with only the desired characteristics has been established.
Basically, a pure line refers to a progeny of a single, homozygous, and self-pollinated plant.

Cytoplasmic sterility is governed by Plasma genes.
Cytoplasmic male sterility is under extranuclear genetic control. It shows non-Mendelian inheritance, with male sterility inherited maternally.
In general, there are two types of cytoplasm: N (normal) and aberrant S (sterile) cytoplasms.
And plasma genes are a self-replicating extranuclear determiner of hereditary characteristics.

If the plant is infected with one disease, it makes the plant resistant to other diseases. This phenomenon is known as Cross protection.
Cross-protection, also known as “pre-immunization" is a method of plant virus control, whereby a plant is deliberately infected with a mild strain of a virus to protect the plant against damage caused by a more severe strain of the same virus.

The concept of physiological races was given by Barrus (1911).
Physiological races are strains of a single pathogen species differing in their ability to attack different varieties of the same host species.
The physiological race is a biotype or group of biotypes within a taxonomic group distinguished by some physiological peculiarity as host preference, chemical dependence, or pathogenicity used especially of economically important fungi, insects, or bacteria.

Dr. Har Govind Khurana was awarded the Nobel Prize in 1968 for his work on Genetic code and in vitro synthesis of DNA.
Har Gobind Khorana was an Indian American biochemist. While on the faculty of the University of Wisconsin-Madison, he shared the 1968 Nobel Prize for Physiology or Medicine with Marshall W. Nirenberg and Robert W. Holley for research that showed the order of nucleotides in nucleic acids, which carry the genetic code of the cell and control the cell's synthesis of proteins.

Protein synthesis takes place in Ribosome.
A ribosome is an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell.
The ribosome reads the messenger RNA (mRNA) sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to synthesize proteins.

Selfing reduces heterozygosity.
Selfing (self-pollination) is the ultimate form of inbreeding or mating among close relatives. It can create yield loss when inbreeding depression, defined as a lower survival and reproduction of inbred relative to outbred progeny, is present.
Selfing increases homozygosity and reduces heterozygosity at a rate of 0.50 per generation. Increased homozygosity can uncover recessive deleterious variants and lead to inbreeding depression unless it is countered by the loss of these variants by genetic purging.

The wide crossing is also known as distant hybridization.
Wide crossing refers to the process of undertaking a cross where one parent is from outside the immediate gene pool of the other.
Wide hybridization or distant hybridization is crossing between two different species or genera and has been used successfully to move genes and to create new crop species.

The seed multiplication ratio of rapeseed red gram, hybrid maize, sorghum and jute is 1 : 100.
The seed Replacement Ratio is a measure of how much of the total cropped area was sown with certified seeds in comparison to farm-saved seeds.
The process of seed planning involves the use of the Seed Multiplication Ratio (SMR) in the computation and estimation of seed demand in the country.

Helper T-cells are the component of the immune response that is crippled in AIDS.
HIV can destroy CD4 cells by direct virus cytotoxicity and indirectly through the host response against HIV-infected cells or gp120-targeted cells.
Cells of the macrophage lineage are generally not destroyed but serve as a reservoir of the virus. HIV also causes functional impairment in T cells, B cells and monocytes.