Chapter Exam

Chapter 9: Plant Breeding — Online MCQ Test

Q: The process of introducing a plant into a new locality where it was not grown before is called plant introduction. The adaptation of this introduced plant to the new environment is known as:

Answer: A. Acclimatization — Acclimatization is the process of adaptation of an introduced plant variety to its new climatic and environmental conditions.

Q: In hybridization, the removal of anthers from the bisexual flower of a female parent before they dehisce is called:

Answer: C. Emasculation — Emasculation is the removal of stamens or anthers of a flower without affecting the female reproductive organs, preventing self-pollination.

Q: Triticale is the first man-made cereal (allopolyploid) crop. It was obtained by crossing:

Answer: B. Wheat and Rye — Triticale is produced by crossing wheat (Triticum durum or Triticum aestivum) with rye (Secale cereale).

BOTANY · CLASS 12th · Tamil Nadu State Board

Practice Chapter 9: Plant Breeding with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 12th BOTANY. This chapter covers: Exploring agricultural botany this chapter covers plant introduction selection hybridization and mutation breeding methods. Students study polyploidy breeding disease resistance de.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 9: Plant Breeding — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 12th BOTANY — Chapter 9: Plant Breeding, with answers and explanations. These are sample questions; the exam has its own separate question set.

The process of introducing a plant into a new locality where it was not grown before is called plant introduction. The adaptation of this introduced plant to the new environment is known as:

A. Acclimatization ✓
B. Hybridization
C. Domestication
D. Selection

Answer: A. Acclimatization
Acclimatization is the process of adaptation of an introduced plant variety to its new climatic and environmental conditions.

In hybridization, the removal of anthers from the bisexual flower of a female parent before they dehisce is called:

A. Bagging
B. Tagging
C. Emasculation ✓
D. Detasseling

Answer: C. Emasculation
Emasculation is the removal of stamens or anthers of a flower without affecting the female reproductive organs, preventing self-pollination.

Triticale is the first man-made cereal (allopolyploid) crop. It was obtained by crossing:

A. Wheat and Rice
B. Wheat and Rye ✓
C. Rye and Barley
D. Rice and Rye

Answer: B. Wheat and Rye
Triticale is produced by crossing wheat (Triticum durum or Triticum aestivum) with rye (Secale cereale).

A plant breeder wants to improve a self-pollinated crop. They choose to use Pure Line Selection instead of Mass Selection. Which of the following is a primary reason for this choice?

A. Pure line selection takes much less time and effort than mass selection.
B. Pure line selection yields progeny that are highly heterozygous and adaptable.
C. Pure line selection results in a highly uniform, homozygous crop where all plants have the same genotype. ✓
D. Pure line selection allows for easy identification and screening of environmental variations.

Answer: C. Pure line selection results in a highly uniform, homozygous crop where all plants have the same genotype.
Pure line selection involves selecting single superior self-pollinated plants and growing their progenies. It produces a highly uniform, homozygous variety because all plants in a pure line have the same genetic constitution.

Hexaploid Triticale (2n = 6x = 42) is developed from a cross between Triticum durum (tetraploid wheat, 2n = 4x = 28, genome AABB) and Secale cereale (rye, 2n = 2x = 14, genome RR). What is the genomic constitution of the sterile F1 hybrid before chromosome doubling, and what is it after doubling?

A. Before: ABR (21 chromosomes); After: AABBRR (42 chromosomes) ✓
B. Before: AB (14 chromosomes); After: AABB (28 chromosomes)
C. Before: ABBR (28 chromosomes); After: AABBBRR (56 chromosomes)
D. Before: AR (14 chromosomes); After: AARR (28 chromosomes)

Answer: A. Before: ABR (21 chromosomes); After: AABBRR (42 chromosomes)
Triticum durum (AABB) produces gametes with AB (n=14) genomes. Secale cereale (RR) produces gametes with R (n=7) genome. The F1 hybrid has genomic constitution ABR (14+7=21 chromosomes) and is sterile. Treatment with colchicine doubles the chromosomes to AABBRR (2n=42), making it fertile.