MCQ on Genetics and Plant Breeding for various Agriculture Exams Part - 12

 

1. Which of the following best describes heterosis?
   a) Inbreeding depression
   b) Hybrid vigor or superiority of hybrids over parents
   c) Genetic drift
   d) Mutation

2. Which term refers to the failure of homologous chromosomes to separate during meiosis?
   a) Crossing over
   b) Nondisjunction
   c) Linkage
   d) Independent assortment

3. Which plant breeding method involves the use of radiation or chemicals?
   a) Hybridization
   b) Backcross breeding
   c) Mutation breeding
   d) Mass selection

4. The main source of genetic variation in sexually reproducing organisms is:
   a) Mutation only
   b) Genetic drift
   c) Recombination during meiosis
   d) Natural selection

5. Which of the following is true for dominant alleles?
   a) They are always beneficial
   b) They mask the expression of recessive alleles
   c) They only occur in homozygous condition
   d) They are always more frequent in populations

6. The F2 generation in a Mendelian monohybrid cross shows:
   a) Only dominant phenotype
   b) Phenotypic ratio of 3:1 dominant to recessive
   c) Genotypic ratio of 1:1
   d) Phenotypic ratio of 9:3:3:1

7. Which of the following best describes “epigenetics”?
   a) Changes in DNA sequence
   b) Heritable changes in gene expression without altering DNA sequence
   c) Gene mutations caused by chemicals
   d) Chromosomal aberrations

8. Which of the following is a biotechnological tool commonly used in plant breeding?
   a) Hybridization
   b) Mutation breeding
   c) Genetic engineering
   d) Backcross breeding

9. Which term describes the genetic makeup of an organism?
   a) Phenotype
   b) Genotype
   c) Allele
   d) Trait

10. What does “linkage disequilibrium” mean?
    a) Genes assort independently
    b) Random mating in population
    c) Non-random association of alleles at different loci
    d) Genetic drift