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TN 12th Computer Applications மின் - வணிகம் Sample Question Papers Study Material - QB365 Set A

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12th Standard Biology English Medium Botany - Plant Breeding 5 Mark Book Back Question Paper and Answer Key 2022 - 2023

Published on: 30/08/2022

QB365 provides a detailed and simple solution for every Possible Book Back Questions in Class 12 Biology Subject - Botany - Plant Breeding, English Medium. It will help Students to get more practice questions, Students can Practice these question papers in addition to score best marks.

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Questions:

Generic 5

2 x 5 = 10

List out the new breeding techniques involved in developing new traits in plant breeding.

What are the different types of hybridization?

Generic 3

1 x 3 = 3

Write a note on heterosis.

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Answers Key:

Generic 5

2 x 5 = 10

(i) Hybridization, Mutation breeding, Polyploid breeding, Breeding for developing resistance to diseases, Biofortification, Breeding for resistance to insect pests, New Breeding Techniques (NBT) such as.
(ii) CRISPR/ Cas (Cutting and modifying the genome during the repair process by tool).
(iii) ODM: Oligonucleotide - directed mutagenesis
(iv) Transferring a gene from an identical or closely related species (Cisgenesis).
(v) Organising processes that alter gene activity without altering the DNA itself (Epigenetic methods).

i. Intravarietal hybridization
The cross between the plants of same variety.
ii. Intervarietal hybridization
The cross between the plants belonging to two different varieties of the same species
iii. Interspecific hybridization
The cross between the plants belonging to different species belonging to the same genus
Example: Gossypium hirsutum x Gossypium arboretum - Deviraj.
IV. Intergeneric hybridization
The crosses between the plants belonging to two different genera.
Example: Raphanobrassica and Triticale.

Generic 3

1 x 3 = 3

Euheterosis: True heterosis
(i) Mutational Euheterosis: Simplest type Often lethal, recessive mutant genes from cross pollinated genes.
(ii) Balanced Euheterosis: Well balanced gene combinations, more adaptive to environmental conditions and agricultural.
Pseudo heterosis: Also called luxuriance, has superiority over parents in vegetative growth but not in yield and adaptation, usually sterile or poorly fertile.