Genetics And Plant Breeding - Study Mode

[#641] The unblended expression of two different alleles for a trait in the phenotype of heterozygous individual is called as
Correct Answer

(D) Co-dominance

Explanation

Solution: The unblended expression of two different alleles for a trait in the phenotype of a heterozygous individual is called Co-dominance. Co-dominance, refers to a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual. Gregor Mendel discovered the phenomenon of co-dominance while studying polygenetic traits and their inheritance.

[#642] The minimum number of primary sample to be taken from seed lot for having lot size 50 - 500 kg is
Correct Answer

(B) 6

Explanation

Solution: The minimum number of primary samples to be taken from a seed lot for having a lot size of 50 - 500 kg is 6. A primary sample is a small portion taken at random from different portions in the lot with an object to form a composite sample. Or, the sample which is taken from different bulk seed lot is called the primary sample. It refers to sampling units that are selected in the first (primary) stage of a multi-stage sample ultimately aimed at selecting individual elements.

[#643] Seed replacement rate of pulses is
Correct Answer

(A) 20%

Explanation

Solution: The seed replacement rate of pulses is 20%. Seed Replacement Rate (SSR) or Seed Replacement Ratio is a measure of how much of the total cropped area was sown with certified seeds in comparison to farm-saved seeds. A better seed replacement rate shows a better utilization of Certified/Quality Seeds. Certified seeds are better in productivity, hence the SRR is directly proportional to productivity.

[#644] Multiple alleles are present
Correct Answer

(A) At the same locus in one type of chromosome

Explanation

Solution: Multiple alleles are present at the same locus in one type of chromosome. Multiple alleles exist in a population when there are many variations of a gene present. In organisms with two copies of every gene, also known as diploid organisms, each organism can express two alleles at the same time.

[#645] With the reference to pure line selection in self-pollinated crops, consider the following statements 1. Pure line selection is essentially based on the genotype of the plant. 2. It is effective only for heritable differences. 3. It is ineffective in creating new variations. Which of the statements given above are correct?
Correct Answer

(C) 1 and 3

Explanation

Solution: With the reference to pure line selection in self-pollinated crops, the following statements are correct: 1. Pure line selection is essentially based on the genotype of the plant. 3. It is ineffective in creating new variations. In pure line selection, large numbers of plants are selected from a self-pollinated crop and are harvested individually, individual plant progenies from them are evaluated separately and the best one is released as a pure line variety.