Genetics And Plant Breeding - Study Mode

[#381] Match the following columns: Column I (Term) Column II (Related scientist) a. Genotype and phenotype 1. Shull b. Heterosis 2. Johannsen c. Recurrent selection 3. Hull (1945) d. Over dominance 4. Hull (1945)
Correct Answer

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

Explanation

Solution: a. Genotype and phenotype term is given by Johannsen. The terms 'genotype', 'phenotype', and 'gene' originally had a different meaning from that in Modern Synthesis. These terms were coined in the first decade of the twentieth century by the Danish plant physiologist Wilhelm Johannsen. b. Heterosis term is given by shull. It is the improved or increased function of any biological quality in a hybrid offspring. c. Recurrent selection is given by Hull in 1945. RECURRENT selection in animal breeding refers to Hull's method of selection for specific combining ability with a tester stock. d. Overdominance is given by Hull in 1945. Overdominance is a rare condition in genetics where the phenotype of the heterozygote lies outside the phenotypical range of both homozygous parents.

[#382] The plant type concept was first introduced by
Correct Answer

(A) Jenings (1964)

Explanation

Solution: The plant type concept was first introduced by Jennings (1964). Plant type breeding can be defined as a method of crop improvement which is used to enhance the genetic yield potential through genetic manipulation of Individual plant character.

[#383] Two species belonging to the same genus are identical in morphology which of the following structural characteristics is more useful in distinguishing such species
Correct Answer

(C) Chromosome number and morphology

Explanation

Solution: Two species belonging to the same genus are identical in morphology. Chromosome number and morphology are the structural characteristics that are more useful in distinguishing such species. Similar DNA sequences, biogeographical features, ecological features, and morphological features of the organisms can be used to rank them in a particular genus. The chromosome number of each species is different and based on which they can be easily segregated.

[#384] Choose the wrong feature of transposition is
Correct Answer

(C) Donor and target sites are homologous

Explanation

Solution: Out of the following statement about transposition, A. Transpose recognizes the insertion sequences are correct. B. Transposons may be either excised or moved or replicated if correct. C. Donor and target sites are homologous is incorrect. D. Transposon discovered by McClintock is correct. Transposition is a process by which segments of a chromosome are relocated through the genome. A transposable element is a nucleic acid sequence in DNA that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size. Transposition often results in the duplication of the same genetic material.

[#385] The performance of a double cross hybrid (A × C) × (B × D) can be predicted from the average performance of the combination of
Correct Answer

(B) A × B, A × D, B × C and C × D

Explanation

Solution: The performance of a double cross hybrid (A × C) × (B × D) can be predicted from the average performance of the combination of A × B, A × D, B × C and C × D. The performance of a double cross hybrid is predicted based on the average performance of the four non-parental single cross hybrids. In this method, the predicted performance of each of the three possible double-cross hybrids would be different.