Genetics And Plant Breeding - Study Mode
[#896] Dark reaction of photosynthesis takes place in
Correct Answer
(D) Stroma
Explanation
Solution: The dark reaction of photosynthesis takes place in the stroma. The products of this reaction are sugar molecules and other organic molecules necessary for cell function and metabolism. The dark reaction takes place in the stroma which is an aqueous fluid surrounding the stacks of thylakoids and the cytoplasm.
[#897] Plant breeds manipulate sterility and floral morphology to take advantage of hybrid vigour. Which of the basic methods listed below are utilised for this purpose? 1. Genetic male sterility 2. Self-incompatibility 3. Hybridization 4. Induced mutation 5. Cytoplasmic male sterility Select the correct answer:
Correct Answer
(B) 1, 2 and 5
Explanation
Solution: Plant breeds manipulate sterility and floral morphology to take advantage of hybrid vigour. The basic methods that are listed below are utilized for this purpose: 1. Genetic male sterility- Genic male sterility (GMS) has emerged as an ideal tool to accelerate hybrid breeding. It is the impairment of male reproductive development as a result of underlying genetic causes and leads to the malformation of male gametes and/or pollen. 2. Self-incompatibility- Self-incompatibility (SI) is defined as the inability to produce zygotes after self-pollination in a fertile hermaphrodite plant, which has stamens and pistils in the same flower. 5. Cytoplasmic male sterility- a condition under which a plant is unable to produce functional pollen, is widespread among higher plants. CMS systems represent a valuable tool in the production of hybrid seeds.
[#898] The condition in which a gene in a homozygous recessive condition (aa) masks the effect of one or both members (BB or bb) of another gene pair is known as
Correct Answer
(B) Recessive epistasis
Explanation
Solution: The condition in which a gene in a homozygous recessive condition (aa) masks the effect of one or both members (BB or bb) of another gene pair is known as Recessive epistasis. Recessive epistasis is when the recessive allele of one gene hides the expression of all alleles of another gene. As the masking allele is in this case recessive, this is called recessive epistasis.
[#899] Continous selfing in a plant increases
Correct Answer
(A) Homozygosity
Explanation
Solution: Continuous selfing in a plant increases Homozygosity. Selfing increases homozygosity at a rate of 0.50 per generation. Increased homozygosity can uncover recessive deleterious variants and lead to inbreeding depression unless it is countered by the loss of these variants by genetic purging. Increased homozygosity also weakens the mixing effects of recombination because it takes place between highly similar chromosomes.
[#900] Staggered sowing is followed to make uniform
Correct Answer
(C) Flowering
Explanation
Solution: Staggered sowing is followed to make uniform Flowering. In Staggered Planting, Instead of planting the entire row of vegetables at once, one can plant part of the crop at the beginning of the growing season and then plant more vegetables after a week or two. A new crop will keep coming in as the first one matures. This enables uniform flowering conditions.