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

The reappearance of an ancestral trait after several generations because of recessiveness or masking effects is known as Atavism.
An atavism is a modification of a biological structure whereby an ancestral genetic trait reappears after having been lost through an evolutionary change in previous generations.
Evolutionarily traits that have disappeared phenotypically do not necessarily disappear from an organism's DNA. The gene sequence often remains but is inactive. Such an unused gene may remain in the genome for many generations.

The pure line is the progeny of the nucleus seed.
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.
Nucleus Seed is the initial amount of pure seed of improved variety or parental lines of a hybrid produced under the supervision of the plant breeder who has evolved that variety or hybrid. The nucleus seed is genetically cent percent pure and does not contain other physical impurities.

Male sterility is used for the production of Composite varieties.
A composite variety is a variety developed by mixing the seeds of various phenotypically outstanding lines possessing similarities in various characteristics like height, seed size, seed colour, maturity, etc.
Genetic male sterility is widely used for hybrid seed production of both seed-propagated species and vegetatively propagated species.

A random assortment of genes will occur when the gene is located on a Different chromosome.
Recombination scrambles pieces of maternal and paternal genes, which ensures that genes assort independently from one another.
It is important to note that there is an exception to the law of independent and random assortment for genes that are located very close to one another on the same chromosome because of genetic linkage.

The method(s) used for the fixation of heterosis are Apomixis, Polyploid, and Asexual reproduction.
Apomixis is asexual reproduction without fertilization. Replacement of the seed by a plantlet or replacement of the flower by bulbils were categorized as types of apomixis.
Polyploidy is a condition in which the cells of an organism have more than one pair of (homologous) chromosomes.
Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant.
And lastly, we know that Heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of development, and fertility than both parents.

Embryosac represents Female gametophyte.
The female gametophyte is also commonly called the embryo sac or megagametophyte.
The female gametophyte develops within the ovule and generally consists of three antipodal cells, one central cell, two synergid cells, and one egg cell.

An amphidiploid between B. nigra and B. campestris is B. juncea.
Brassica juncea is an amphidiploid having in its genetic system the full 20-chromosome A genome (Brassica campestris) and the 16-chromosome B genome (Brassica nigra).
Brassica juncea belongs to the mustard family (Brassicaceae or Cruciferae) and has numerous common names used, e.g., brown mustard, Chinese mustard, or oriental mustard.

Cell lineage theory was proposed by Rudolf Virchow.
Cell lineage denotes the developmental history of a tissue or organ from the fertilized embryo.
This is based on the tracking of an organism's cellular ancestry due to the cell divisions and relocation as time progresses, this starts with the originator cells and finishes with a mature cell that can no longer divide.

Coating seeds with biological agents is known as Bio priming.
Bio-priming is a coating process or seed treatment with beneficial PGPR under controlled hydration conditions, which improves the preparatory methods before germination without the emergence of the radicle.
Seed priming with living bacterial inoculum is termed biopriming that involves the application of plant growth-promoting rhizobacteria.
It improves harvest quality and yield of seeds.