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Published on: 12/10/2019
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.
Who am I?
(I) Father of Green Revolution.
(il) Father of Indian Green Revolution
2.
Yesterday, Ramu visited his friend's Orchard, where in he noticed few flowers of certain guava trees are covered using thin paper bags.
(I) Name the process carried out there.
(ii) Why it was done so?
3.
Provide an example for each of the following agricultural components. (i) Bio pesticide (ii) Green manure crop (iii) Bio-FertiIizer
4.
Given below are the examples of symbiotic association in which one partner was mentioned. Write the name of the mutual co-partners.
(a) Azolla fem + _________
(b) Root nodules of legume plants + ______
(c) phycomycetous fungi + ________
5.
Write a short note on autopolyploidy with an example.
6.
Write a note on Green Manuring.
7.
What makes the Trichoderma an effective bio-pesticide?
8.
Mention any three advantages of Arbuscular mycorrhizal association.
9.
Azolla increases the yield of paddy crop - support your answer.
10.
How Rhizobium acts as an efficient bio-fertiIizer?
1.
(i) Dr. Norman E. Borlaug.
(ii) Dr. M.S. Swaminathan.
2.
(i) The process is referred as bagging in plant hybridization.
(ii) It is done after emasculation to protect the contact of the stigma of the flower against any other pollen grain.
3.
(i) Bio pesticide - E.g. Trichoderma species
(ii) Green manure - E.g. Crotalaria juncea
(iv) Bio fertilizer - E.g. Azolla
4.
(a) Anabaena azolla (blue green alga)
(b) Rhizobium
(c) Angiosperm roots
5.
When chromosome number is doubled by itself in the same plant, is called Autopolyploidy. Example: A triploid condition in sugar beets, apples and pear has resulted in the increase in vigour and fruit size, large root size, large leaves, flower, more seeds and sugar content in them. It also resulted in seedless tomato, apple, watermelon and orange
6.
Green manuring is defined as the growing of green manure crops and use of these crops directly in the field by ploughing. One of the main objectives of the green manuring is to increase the content of nitrogen in the soil. Also, it helps in improving the structure and physical properties of the soil. The most important green manure crops are Crotalaria juncea, Tephrosia purpurea, and Indigofera tinctoria.
7.
Trichoderma species are free-living fungi that are common in soil and root ecosystem. They have been recognized as bio-control agent for
(1) the control of plant disease
(2) ability to enhance root growth development
(3) crop productivity
(4) resistance to abiotic stress and
(5) uptake and use of nutrients.
8.
i) Arbuscular mycorrhizae have the ability to dissolve the phosphate found in soil.
ii) Provides resistance against diseases, germs, and unfavorable weather conditions.
iii) It assures water availability.
9.
Azolla is a free-floating water fern that fixes the atmospheric nitrogen in association with nitrogen fixing blue green alga Anabaena azolla. It is used as a bio-fertilizer for wetland rice cultivation and is known to contribute 40 - 60 kg/ha/crop. The agronomic potential of azolla is quite significant particularly for increasing the yield of rice crop, as it quickly decompose in soil.
10.
Bio-fertilizers containing rhizobium bacteria are called rhizobium bio-fertilizer culture. Symbiotic bacteria that reside inside the root nodules convert the atmospheric nitrogen into a bio available form to the plants. This nitrogen-fixing bacterium when applied to the soil undergoes multiplication in billions and fixes the atmospheric nitrogen in the soil. Rhizobium is best suited for the paddy fields which increase the yield by 15 - 40%.
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Tamilnadu Stateboard 12th Standard Subjects

Maths

Chemistry

Physics

Biology

Computer Science

Business Maths and Statistics

Economics

Commerce

Accountancy

History

Computer Applications

Biology

Computer Technology

Computer Applications

Computer Science

Business Maths and Statistics

Commerce

Economics

Maths

Chemistry

Physics

Computer Technology

History

Accountancy

Tamil

English

French
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