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

a. Genotype and phenotype is the term proposed by Johannsen. Wilhelm Johannsen first proposed the distinction between genotype and phenotype in the study of heredity while working in Denmark in 1909.
b. Heterosis is the term given by Shull in 1914. Heterosis, or hybrid vigor, is the improved or increased function of any biological quality in a hybrid offspring.
c. Recurrent selection is proposed by Hull in 1945. Recurrent selection (Hull, 1945a) was meant to include reselection generation after generation, with the interbreeding of selects to provide for genetic recombination.
d. Over-dominance is proposed by Hull in 1945. The overdominance hypothesis postulates that heterosis is due to the superiority per se of heterozygous genotype compared to either parental homozygous genotype at individual loci.

The breeding method for transferring monogenic disease resistance from wild species to an improved variety of wheat is the Backcross method.
Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent.
Backcrossing and/or convergent backcrossing have been used for transferring resistance to desirable agronomic backgrounds. The number of backcrosses needed to achieve agronomically similar derivatives depends on the donor genotype.

A cell without a cell wall is known as Protoplast.
Protoplasts are isolated cells produced by removing the surrounding cell wall either by mechanical means or by the use of cell wall degrading enzymes.
It is a biological term coined by Hanstein in 1880 to refer to the entire cell, excluding the cell wall.
Protoplasts are widely used for DNA transformation (for making genetically modified organisms) since the cell wall would otherwise block the passage of DNA into the cell.

The source of 'A' genome in wheat is T. urartu.
Bread wheat, Triticum aestivum, is a hexaploid comprising an “A” genome from the wild diploid Triticum urartu (Au genome), a “B” genome most likely from Aegilops speltoides, and a “D”genome from Triticum tauschii.
The first cultivated wheat was the diploid Triticum monococcum, einkorn wheat selected from wild T.

Pure line selection is used to improve the self-pollinated crop.
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.
In pure-line selection, a large number of plants are selected from a self-pollinated crop and are harvested individually; individual plant progenies from them are evaluated, and the best progeny is released as a pure-line variety.

The process of double fertilization was discovered by Nawaschin.
The fusion of one sperm with the egg cell to form the embryo and of the other sperm with the polar fusion nucleus to give rise to the endosperm is known as double fertilization, and it was discovered by Nawaschin in 1898 in the liliaceous plants, Lilium martagon and Fritillaria tenella.

Changes in population genetics in which extreme values for a trait are selected over intermediate values are known as Disruptive selection.
Disruptive selection also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values.
In this case, the variance of the trait increases, and the population is divided into two distinct groups. The effect of selection is to promote certain alleles, traits, and individuals that have a higher chance to survive and reproduce in their specific environment.

a. HB-1 is the hybrid variety of Pearl millet. The first pearl millet hybrid HB 1 was released in 1965 thus making India the first country in the world to develop a grain hybrid utilizing a cytoplasmic-genetic male-sterile line and a restorer line.
b. Ganga-1 is the hybrid variety of Maize. The first hybrid maize Ganga-1 was developed in India in 1961.
c. Pusa RH-10 is the hybrid variety of Basmati rice. Pusa Rice Hybrid 10 (PRH 10) is the first aromatic Basmati Hybrid developed by the public sector Agricultural Research Institute and released by Central Variety Release Committee (CVRC) in 2001.
d. CSH-1 is the hybrid variety of Sorghum. The first sorghum hybrid, CSH1 (Coordinated Sorghum Hybrid), was bred in India and officially released for commercial cultivation in 1964.

The number of single crosses will be equal to $$\frac{{{\text{n}}\left( {{\text{n}} - 1} \right)}}{2}.$$
The term "single cross" means the first-generation hybrid between two inbred lines.
The type of hybrid that is produced when two different inbreds are cross-pollinated, which is also known as an F1 hybrid, are inbreds. Each seed produced from crossing two inbreds has an array (collection) of alleles from each parent.

Mitotic apparatus consists of a Mitotic spindle, Aster ray along the centriole,and Matrix.
The mitotic spindle apparatus is a microtubule-based structure responsible for chromosome segregation during cell division. Microtubules within the spindle are classified according to their plus-end interactions.
The mitotic spindle is a special device essential for chromosome segregation (mitosis) during cell division.
In eukaryotic cells, the mitotic apparatus is composed of two centrosomes and spindle microtubules. The centrosome is 1 - 2 μm in diameter.