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Published on: 22/01/2020
Botany - Plant Breeding
Download Tamil Nadu 12th Standard Biology question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Biology Test1.
Name the insect resistant varieties developed in the following crops.
(a) Okra (b) Rapeseed mustard.
2.
What is Biofortification?
3.
Name any two allopolyploid plant species
4.
What are polyploids? Mention its nature.
5.
State anyone advantage and one disadvantage of polyploid breeding.
6.
Write in brief about Atomic Garden.
7.
Mutagens are the substances that induces mutation. Name any two physical and chemical mutagens.
8.
What does the term 'luxuriance' stands for in plant breeding? Explain.
9.
Define Heterosis?
10.
Define the following terms:
(a) Emasculation
(b) Bagging
11.
Define acclimatization.
12.
Name any four plants used in Green leaf manuring
13.
What are bio-pesticides? Why they are considered better than synthetic pesticides?
14.
Mention any two free-living nitrogen-fixing bacteria.
15.
What is meant by domestication of plants?
1.
(a) Okra: Pusa Sawani and Pusa A-4 varieties of Okra are resistant to shoot and fruit borers.
(b) Rapeseed mustard: Pusa Gaurav variety of rapeseed mustard shown resistance against Aphids.
2.
Breeding crops with high vitamin, mineral, protein and fat.
3.
Triticale (Triticum durum x Secale cereale).
Raphanobrassica (Brassica oleraceae x Raphanus sativus).
4.
Majority of flowering plants are diploid (2n). The plants which possess more than two sets of chromosome are called polyploids. Polyploidy often exhibit increased hybrid vigour, increased heterozygosity, increase the tolerance to both biotic and abiotic stresses and buffering of deleterious mutations.
5.
Advantage: Polyploidy often exhibit hybrid vigour and increased tolerance to biotic and abiotic stresses.
Disadvantage: Polyploidy results in reduced fertility due to meiotic error resulting in seedless varieties.
6.
Atomic Garden: Is a form of mutation breeding where plants are exposed to radioactive sources typically cobalt-60 or caesium-137 in order to generate desirable mutation in crop plants
7.
UV short waves, X-rays - Physical mutagens.
Nitromethyl, Urea - Chemical mutagens.
8.
Pseudo heterosis - Also termed as luxuriance. Progeny possess superiority over parents in vegetative growth but not in yield and adaptation, usually sterile or poorly fertile
9.
The superiority of the F1 hybrid in performance over its parents is called heterosis or hybrid vigour.
10.
Emasculation: It is a process of removal of anthers to prevent self-pollination before anthesis (period of opening of a flower).
Bagging: The stigma of the flower is protected against any undesirable pollen grains, by covering it with a bag.
11.
The newly introduced plant has to adapt itself to the new environment. This adjustment or adaptation of the introduced plant in the changed environment is called acclimatization.
12.
(a) Cassia fistula
(b) Sesbania grandiflora
(c) Azadirachta indica
(d) Pongamia pinnata
13.
Bio-pesticides are biologically based agents used for the control of plant pests. They are in high use due to their non-toxic, cheaper and eco-friendly characteristics as compared to chemical or synthetic pesticides.
14.
Azotobacter and Clostridium
15.
Domestication is the process of bringing a plant species under the control of humans and gradually changing it through careful selection, genetic alteration and handling so that it is more useful to people.
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