Genetics And Plant Breeding - Study Mode

[#481] In gametophytic system of self-incompatibility fully incompatible will result from a cross between
Correct Answer

(A) S 1 S 2 × S 1 S 2

Explanation

Solution: In the gametophytic system of self-incompatibility fully incompatible will result from a cross between S 1 S 2 × S 1 S 2 . Gametophytic self-incompatibility, involves the inability of the gametes from the same parent plant to fuse and form a zygote or, if the zygote forms, then it fails to develop. These systems force outcrossing and maintain a wide genetic diversity.

[#482] Method of creating variation in asexually propogated crop is
Correct Answer

(B) Polyploidy

Explanation

Solution: The method of creating variation in asexually propagated crops is Polyploidy. The fusion of two or more genomes within one nucleus results in polyploidy, resulting in each cell containing more than two pairs of homologous chromosomes. Polyploidy occurs in the majority of angiosperms and is important in crops that humans depend on for survival at the same time it serves as the method of creating variation in asexually propagated crops.

[#483] A male plant of chromosome pp pollinates the plant having chromosome type PP. The expected chromosome in embryo and endosperm
Correct Answer

(C) Embryo-Pp, Endosperm-PPp

Explanation

Solution: A male plant of chromosome pp pollinates the plant having chromosome type PP. The expected chromosome in embryo and endosperm will be Embryo-Pp, Endosperm-PPp. An embryo is a simple multicellular structure of undifferentiated cells. And embryonic development is seen only in the diploid generation. The embryo, however, is produced by the fusion of gametes, which are formed only by the haploid generation. Thus it is Pp. An endosperm formed in sexual reproduction between diploid parents is typically triploid thus, it is PPp.

[#484] Match the following columns: Column I Column II a. B-chromosomes 1. Reduction b. Mitosis is also known as 2. Leucoplasts c. Meiosis is also known as 3. Equitional division d. The colourless plastids are known as 4. Extrachromosome
Correct Answer

(C) a-4, b-3, c-1, d-2

Explanation

Solution: a. B-chromosomes are extrachromosomal. B chromosomes are extra chromosomes to the standard complement that occur in many organisms. They can originate in several ways including derivation from autosomes and sex chromosomes in intra- and interspecies crosses. b. Mitosis is also known as Equational division. Mitosis is the process of cell division wherein the chromosomes replicate and get equally distributed into two daughter cells, therefore it is also known as equational division. c. Meiosis is also known as Reduction. Meiosis is sometimes called "reduction division" because it reduces the number of chromosomes to half the normal number. d. The colourless plastids are known as Leucoplasts. Leucoplasts are colourless plastids and mainly help in the storage of food compounds like starch, proteins or fats.

[#485] Concept of single seed descent method was developed by
Correct Answer

(A) Goulden (1939)

Explanation

Solution: The concept of the single-seed descent method was developed by Goulden (1939). SSD is the modification of the bulk method. It is first proposed by Goulden (1939) and later modified by Brim (1966). Instead of bulking a whole seed lot of selected plants, a single seed is selected randomly from each selected plant to make bulk. The SSD method consists of advancing hybrid populations by taking a single seed from each plant and compositing the seeds to perpetuate the next generation.