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

Before reaching adulthood some individuals die because of the presence of the gene in the appropriate genotype Lethal gene.
This gene causes death if both recessive alleles are possessed by the same individual.
They are usually a result of mutations in genes that are essential for growth or development. Lethal alleles may be recessive, dominant, or conditional depending on the gene or genes involved.
Recessive lethal alleles do not cause death in the heterozygous form because a certain threshold of protein output is maintained. In the homozygous form, the protein output does not meet the threshold, causing death.

Self-incompatibility is helpful for the development of Pure line variety.
Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms and thus encourage outcrossing and allogamy. SI is one of the most important means of preventing inbreeding and promoting the generation of new genotypes in plants.
A pure line is the progeny of a single self-fertilized homozygous plant. Therefore self-incompatibility is helpful in the development of pure line varieties.

Root pressure is responsible for guttation.
Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses, and several fungi, which are not plants but were previously categorized as such and studied as part of botany.
The root pressure forces some water to exude through special leaf tip or edge structures, hydathodes, or water glands, forming drops. Root pressure provides the impetus for this flow, rather than transpirational pull.

The crossing between two different species of the same genus is called Interspecific hybridization.
Interspecific hybridization is the crossing of two species from the same genus. This allows the exploitation of useful genes from wild, unimproved species for the benefit of the cultivated species.
The Pisum species are diploid self-pollinators sharing a similar karyotype.

A. Operon concept-Jacob and Monod is correct match.
Operon Theory is the concept of gene regulation proposed by François Jacob and Jacques Monod (1961). An operon is a group of structural genes whose expression is coordinated by an operator.
B. Transposons-McClintock is correct match.
The existence of transposons was postulated in the late 1940s by Barbara McClintock, who was studying the inheritance of maize, but the actual molecular basis for transposition was described by later groups.
C. Khorana-Genetic code is also a correct match.
Har Gobind Khorana was the chemist who cracked DNA's code and made the first artificial gene. genetic code is the once-secret language of our DNA.

Genetic assortative mating is useful in developing Inbreds.
Assortative mating, in human genetics, is a form of non-random mating in which pair bonds are established based on phenotype.
The closest type of genetic assortative mating is selfing. It results in homozygosity and fixation of types, therefore, is useful to develop homozygous lines and development of inbred lines for hybrid or synthetic cultivars.

The phenotypic ratio of complementary gene action is 9 : 7.
Any hybrid cross of complementary genes gives a phenotypic ratio of 9 : 7.
A phenotypic ratio is a quantitative relation between phenotypes showing the number of times the frequency of one phenotype correlates with another.
Complementary gene action is when two different genes work together to contribute to one single trait.

The concept of crop ideotype was developed by Donald (1968).
An ideotype is a specimen identified as belonging to a specific taxon by the author of that taxon but collected from somewhere other than the type locality.
The concept of ideotype in plant breeding was introduced by Donald in 1968 to describe the idealized appearance of a plant variety. It means a form denoting an idea'.
According to Donald, an ideotype is a biological model which is expected to perform or behave in a particular manner within a defined environment.

Somatic Hybridization is achieved through Protoplast fusion.
Somatic fusion, also called protoplast fusion, is a type of genetic modification in plants by which two distinct species of plants are fused to form a new hybrid plant with the characteristics of both, a somatic hybrid.
Somatic hybridization and cybridization have great potential for plant improvement. Somatic hybridization through protoplast fusion provides the ability to combine parent genes in higher plants to overcome sexual incompatibility among plant species or genera.