Genetics And Plant Breeding - Study Mode

[#246] The method(s) used for fixation of heterosis are
Correct Answer

(D) All of these

Explanation

Solution: 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.

[#247] Embryosac represents
Correct Answer

(C) Female gametophyte

Explanation

Solution: 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.

[#248] An amphidiploid between B. nigra and B. campestris is
Correct Answer

(C) B. juncea

Explanation

Solution: 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.

[#249] Cell lineage theory was proposed by
Correct Answer

(C) Virchow

Explanation

Solution: 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.

[#250] Coating of seeds with biological agents is known as
Correct Answer

(B) Bio priming

Explanation

Solution: 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.