Genetics And Plant Breeding - Study Mode
[#821] With reference to self-incompatibility, consider the following statements 1. Sporophytic system of self-incompatibility is governed by a single gene with multiple alleles. 2. The incompatibility reaction of pollen is governed by the genotype of the plant on which pollen is produced. 3. The 's' alleles are responsible for sporophytic incompatibility 4. Failure of pollen germination on stigma, slow pollen tube growth after pollination are some of the reasons for this self-incompatibility. Which of the statements given above are correct?
Correct Answer
(D) All of the above
Explanation
Solution: Concerning self-incompatibility, all four statements are correct. Self-incompatibility is a widespread mechanism in flowering plants that prevents inbreeding and promotes outcrossing. The sporophytic system of self-incompatibility is governed by a single gene with multiple alleles.
The incompatibility reaction of pollen is governed by the genotype of the plant on which pollen is produced. The 's' alleles are responsible for sporophytic incompatibility. Failure of pollen germination on stigma, and slow pollen tube growth after pollination are some of the reasons for this self-incompatibility.
[#822] The component lines used in development of composite variety of maize are
Correct Answer
(D) Open pollinated varieties
Explanation
Solution: The component lines used in the development of a composite variety of maize are Open-pollinated 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. Crossing among the selected varieties is possible because the species used are open-pollinated.
[#823] The cDNA libraries can be prepared by isolating
Correct Answer
(B) mRNA
Explanation
Solution: The cDNA libraries can be prepared by isolating mRNA. The creation of a cDNA library starts with mRNA instead of DNA. Messenger RNA carries encoded information from DNA to ribosomes for translation into protein. To create a cDNA library, these mRNA molecules are treated with the enzyme reverse transcriptase, which is used to make a DNA copy of an mRNA.
[#824] The concept of epigenesis was proposed by
Correct Answer
(A) Wolff
Explanation
Solution: The concept of epigenesis was proposed by Wolff. The theory of epigenesis was formulated by the German physician and naturalist C. F. Wolff (1734 - 1794). It refers to the development of a plant or animal from an egg or spore through a series of processes in which unorganized cell masses differentiate into organs and organ systems.
[#825] The stamens in cruciferae are
Correct Answer
(C) Tetradidynamous
Explanation
Solution: The stamens in cruciferae are Tetradynamous. Cruciferae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. The flowers have four free sepals, four free alternating petals, two shorter free stamens, and four longer free stamens. This condition of stamen is termed Tetradynamous.