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

The crossing-over takes place in Pachytene.
Pachytene is the stage of meiotic prophase that immediately follows the zygotene and is characterized by paired chromosomes thickened and visibly divided into chromatids and by the occurrence of crossing-over.
During this stage, exchanges of chromosome material between maternal and paternal homologous chromosomes occur by crossing over. At the points of crossing over, bridges (chiasmata) are seen in variable numbers. Depending on the chiasmata, different aspects of the chromosomes can be observed.

The increased performance of F₁ hybrid over its parents is called Heterosis.
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.
Various models have been posited to explain heterosis, including dominance, overdominance and pseudo-overdominance.

If the host plant is susceptible to the pathogen at a young age and becomes resistant with age then it possesses Adult plant resistance.
Resistance is the ability of a plant variety to restrict the growth and development of a specified pest or pathogen and/or the damage they cause when compared to susceptible plant varieties under similar environmental conditions and pest or pathogen pressure.

Out of the following given options Ribozyme is not a protein.
Ribozymes are catalytically active RNA molecules or RNA-protein complexes, in which solely the RNA provides catalytic activity. The term ribozyme refers to the enzymatic activity and ribonucleic acid nature at the same time.
Ribozymes are found in the genomes of species from all kingdoms of life.

Distant hybridization is associated with Hybrid inviability, Hybrid sterility and Hybrid breakdown.
Distant hybridization refers to crosses between two different species, genera, or higher-ranking taxa, which can break species limits, increase genetic variation, and combine the biological characteristics of existing species.
Hybrid inviability is a post-zygotic barrier, which reduces a hybrid's capacity to mature into a healthy, fit adult.
Hybrid sterility is defined as the inhibition or suppression of the reproductive capacity of F1 or later-generation hybrids between genetically different strains or populations, usually belonging to different species.
The hybrid breakdown is a type of reproductive failure that appears after the F2 generation of crosses between different species or subspecies. It is caused by incompatibility between interacting genes.

Rice inflorescence is called a Panicle.
Panicles form the rice inflorescence. It is the top part of the rice plant, carried on the last inter-node. Panicles are composed of primary ramifications (small branches) that carry secondary branches themselves carrying the pedicels which carry the spikelets.
The inflorescence of the rice plant is borne on terminal shoots and is thus called a panicle. It is the determinate type and at maturity, it is droopy.

The first sorghum hybrid was released in 1964.
Sorghum hybrid development involves the development of parental lines based on a cytoplasmic male sterile system including the pollen parent (R-line) and seed parents (A- and B-lines).
The spread of modern hybrids and varieties of sorghum in India began in the late 1960s, with the release in 1964 of the first high-yielding hybrid CSH-1 developed by Dr. N. Ganga Prasada Rao, and the equally high-yielding variety Swarna in 1968, also developed by him.

The maize inbreeds are maintained by Selfing.
The nucleus seed of inbred lines can be maintained by self-pollination, sib-pollination, or a combination of the two procedures (hand pollination). Some breeders prefer 'sibbing" because it maintains vigour. "Selfing" is used to stabilize inbred lines if a change in breeding behavior is noticed.
Selfing or self-pollination, where ovules are pollinated by the plant's pollen, is the ultimate form of inbreeding or mating between relatives.

Diffused centromere means Centromere is nonlocalized and spread over the chromosome.
Diffuse centromeres - in asexual organisms where the offspring is an exact genetic copy of the parent, there are limited sources of genetic variability.
The chromosomes are characterized by large size, sinuous shape, and sticky matrix; the chromatids are parallel at anaphase, separate at metaphase throughout their length; the centromere is 'diffuse'.