b) Assertion is wrong and reason is right.
a) Centres of origin
c) Clonal selection – Sexually propagated
The matching of Column I with Column II is as follows: i - III, ii - I, iii - IV, iv - II. This type of question typically involves associating terms or concepts in one column with their corresponding definitions, examples, or related items in the other column. Without the content of Column I and Column II, a detailed explanation cannot be provided, but the answer indicates a specific pairing has been correctly identified according to the question's requirements.
b) Selection
b) hybridization
a) clone
d) Introduction
c) Norin 10
c) Intra varietal
b) Pure line
b) Rice
b)Saccharum barberi and Saccharum officinarum
b) I-(ii), II-(i), IH-(iii), IV-(iv)
c) proteins
a) Pusa Komal – Bacterial blight
d) Pusa Komal – Brassica
The correct matching of biofertilizers with their corresponding organisms is: Free-living Nitrogen fixers include Azotobacter and Anabaena azollae. Symbiotic Nitrogen fixers include Rhizobium (though not listed, it's a key example) and Anabaena (in association with Azolla). Phosphorus Solubilizing organisms include Aspergillus. Phosphorus Mobilizing organisms include bacteria that make insoluble phosphates available. Based on the options, the correct match is: i. Free living N2 - Azotobacter (d), ii. Symbiotic N2 - Anabaena azollae (c), iii. P Solubilizing - Aspergillus (a), iv. P Mobilizing - (b) which likely refers to a P-solubilizing or mobilizing agent not explicitly named but fits the pattern. Thus, the correct option is b. i d, ii c, iii a, iv b.
The correct matching of the scientists and their contributions to plant breeding is: Darwin's evolutionary theory is associated with Natural Selection and Hybridization (a-iv). Vavilov is known for identifying 12 mega gene centers of crop diversity (b-ii). Zhukovsky further elaborated on these centers, often cited as 12 main geographic centers (c-iii). De Candolle is recognized for his work on the Origin of Cultivated Plants (d-i). Therefore, the correct option is A) a – iv, b – ii, c – iii, d – i.
d) South America – Onion
C) Dr. K. Ramiah – Wheat breeder
a) N2 Fixing Bacteria – Bacillus
c) Green Manuring – Sonora-63 is the incorrect pair. Sonora-63 is a wheat variety, not a green manuring crop. The correct matching should be: Free Living fungi – Trichoderma, Entomopathogenic – Beauveria, Green Manuring – Cassia fistula, and Green Leaf Manure – Sonora-63 would be incorrect as Sonora-63 is a cereal variety used in the Green Revolution, not a green manure crop.
b) Blast resistant Rice -1940
a) Green Manuring – Tephrosia purpurea
The correct matching of breeding methods, varieties, and scientists is: Mutational Breeding is exemplified by the development of semi-dwarf wheat varieties (4) which often involved induced mutations. Polyploid Breeding is a key technique used in developing varieties like Triticale (1). M.S. Swaminathan is a renowned Indian plant breeder who made significant contributions, including work on semi-dwarf varieties and hybrid rice (3. TN 1 – hybrid rice is an example, though Jaya and Ratna (d) are also semi-dwarf rice varieties he worked with). Jaya and Ratna (d) are semi-dwarf rice varieties. Atomita-2 (b) is a variety of durum wheat. Therefore, the most fitting match is c) M.S. Swaminathan – TN 1 – hybrid rice, implying his association with such advancements.
The correct matching of crop with its disease-resistant variety is: Wheat is represented by Himgiri (3), which is resistant to leaf and stripe rust. Cow pea variety Pusa Komal (1) is resistant to bacterial blight. Brassica, specifically mustard, has varieties like Pusa Sadabahar (2) which is resistant to white rust and aphid. Cauliflower variety Pusa Shubhra (4) is resistant to black rot and mosaic. Thus, the correct option is d) Cauliflower – Pusa shubhra.
The correct matching of geographical centers of origin for crops with specific crops is: Mesoamerica is a center of origin for crops like Maize and Guava (iii). South East Asia is recognized as a center for crops such as Rice and Bamboo (iv). The Abyssinian center is associated with crops like Sorghum and Teff, but among the options, Hemp (iv) is also sometimes linked to this broader region or related centers. China is a center for Soybeans and Millet, and also associated with Hemp (iv). Given the options, a plausible matching is: Mesoamerica (a) - Guava (iii), South East Asia (b) - Bamboo (iv), Abyssinian (c) - Sesame (i), China (d) - Hemp (iv). However, looking at common textbook associations, a more standard match is: Mesoamerica (a) - Guava (iii), South East Asia (b) - Bamboo (iv), Abyssinian (c) - Hemp (iv), China (d) - Sesame (i). Re-evaluating the provided options, option D suggests: a – iii (Mesoamerica - Guava), b – iv (South East Asia - Bamboo), c – i (Abyssinian - Sesame), d – iv (China - Hemp). This seems to have a repetition for 'iv'. Let's assume a standard match: Mesoamerica (a) - Guava (iii), South East Asia (b) - Bamboo (iv), Abyssinian (c) - Hemp (iv), China (d) - Sesame (i). If we strictly follow the provided options and assume a typo in the question or options, option D: a – iii, b – iv, c – i, d – iv is the closest if we interpret 'iv' for China as Hemp. A more accurate standard matching would be: Mesoamerica (a) - Guava (iii), South East Asia (b) - Bamboo (iv), Abyssinia (c) - Hemp (iv), China (d) - Sesame (i). If we must choose from the given options, and assuming a possible error in the provided options, let's re-examine. Option D: a – iii, b – iv, c – i, d – iv. This implies Mesoamerica-Guava, SE Asia-Bamboo, Abyssinian-Sesame, China-Hemp. This is a plausible, though not universally agreed upon, matching. Let's proceed with D as the intended answer based on the provided format.
The correct matching of terms related to plant breeding and specific examples is: Atomic Garden is a facility for studying the effects of radiation, often involving sources like Caesium 137 (b-ii). Protein Enriched varieties are exemplified by French Peas (c-iii), known for higher protein content. Vitamin C Enriched varieties include Bitter Gourd (d-iv), which is rich in Vitamin C. Dwarfing Genes (a-i) are crucial for developing semi-dwarf varieties like Norin 10 (a-i). Therefore, the correct option is B) a – ii, b – iii, c – iv, d – i. Let's re-evaluate based on the provided answer B) a – ii, b – iii, c – iv, d – i. This implies: a. Atomic Garden - Dwarfing Genes (Incorrect). b. Protein Enriched - Caesium 137 (Incorrect). c. Vitamin C Enriched - French Peas (Incorrect). d. Norin 10 - Bitter Gourd (Incorrect). There seems to be a significant mismatch. Let's try to match based on common knowledge: a. Atomic Garden - Caesium 137 (b-ii). b. Protein Enriched - French Peas (c-iii). c. Vitamin C Enriched - Bitter Gourd (d-iv). d. Norin 10 - Dwarfing Genes (a-i). This gives the matching: a-i, b-ii, c-iii, d-iv. The provided answer is B) a – ii, b – iii, c – iv, d – i. This implies: a. Atomic Garden - Dwarfing Genes (Incorrect). b. Protein Enriched - Caesium 137 (Incorrect). c. Vitamin C Enriched - French Peas (Incorrect). d. Norin 10 - Bitter Gourd (Incorrect). There appears to be a significant error in the provided options or the intended matching. Let's assume the question meant to match Column A with Column B directly. If we use the provided answer B) a – ii, b – iii, c – iv, d – i, it suggests: a. Atomic Garden corresponds to Dwarfing Genes (Incorrect). b. Protein Enriched corresponds to Caesium 137 (Incorrect). c. Vitamin C Enriched corresponds to French Peas (Incorrect). d. Norin 10 corresponds to Bitter Gourd (Incorrect). Let's assume the answer key provided (B) is correct and try to make sense of it, although it seems highly problematic. If B is correct, then: a. Atomic Garden is matched with Dwarfing Genes (ii). b. Protein Enriched is matched with Caesium 137 (iii). c. Vitamin C Enriched is matched with French Peas (iv). d. Norin 10 is matched with Bitter Gourd (i). This mapping is biologically and scientifically incorrect. There is likely an error in the question or the provided answer key. However, if forced to select based on the provided answer B, the mapping is as stated above, despite its inaccuracies.
c) a-iii, b-i, c-ii, d-iv. The correct matching is: Green Revolution – William S. Gaud (a-iii), Mutation Breeding – Muller and Stadler (b-i), Heterosis – G.H. Shull (c-ii), and Director of IARI – Dr. B.P. Pal (d-iv). These represent the key scientists and concepts associated with major developments in plant breeding and agricultural improvement.
Primary introduction refers to the introduction of a plant variety to a new geographical region where the introduced variety is well adapted to the new environment and there is no alteration to the original genotype. The variety maintains its genetic constitution and is directly cultivated in the new region. Secondary introduction, on the other hand, involves the introduction of a plant variety that is subsequently subjected to selection and improvement. The introduced variety may be hybridized with local varieties to transfer one or a few desirable characters to them, creating new improved varieties suited to local conditions. For example, tea varieties collected from China and North East India were initially grown in the Botanical Garden of Kolkata as primary introductions, from which appropriate clones were selected and introduced to different parts of India as secondary introductions, resulting in improved tea varieties adapted to various Indian regions.
Biofertilizers or microbial inoculants are preparations containing living cells or latent cells of efficient strains of microorganisms that enhance crop plant nutrient uptake through their interactions in the rhizosphere when applied through seed or soil. These microbial inoculants are efficient in fixing atmospheric nitrogen, solubilizing insoluble phosphate compounds, and decomposing cellulose in the soil. They are specifically designed to improve soil fertility, promote plant growth, and increase the number and biological activity of beneficial microorganisms in the soil ecosystem. Common biofertilizers include nitrogen-fixing bacteria like Azotobacter and Rhizobium, phosphate-solubilizing bacteria, and mycorrhizal fungi. These microbial inoculants represent ecofriendly organic agro-inputs that are more efficient and cost-effective than chemical fertilizers, reduce environmental pollution, improve soil health, and promote sustainable agriculture. They enhance nutrient availability to plants in forms that are readily absorbed, thereby reducing the need for synthetic fertilizers and contributing to environmentally sustainable farming practices.
Types of hybridization:
(i) Intravarietal hybridization:
The cross between the plants of same variety. such crosses are useful only in the self. pollinated crops.
(ii) Intervarietal hybridization:
The cross between the plants belonging to two different varieties of the same species and is also known as intraspecific hybridization.
(iii) Interspecific hybridization:
The cross between the plants belonging to different species belonging to the same genus is also called intragenic hybridization.
Example:
Gossypium hirsutum
Gossypium arboreum
(v) Intergeneric hybridization:
* The crosses are made between the plants belonging to two different genera.
* The disadvantages are hybrid sterility time consuming and expensive procedure.
Example: Raphanobrassica x Triticale
Mutation breeding represents an advanced method that complements conventional breeding procedures and has significant advantages in improving crop defects without losing important agronomic and quality characters in agriculture and crop improvement. Mutation refers to sudden heritable changes in the genotype or phenotype of an organism caused by alterations in the DNA sequence. Gene mutations are of considerable importance in plant breeding as they provide essential genetic variation for evolution, recombination, and selection. Mutations can be induced artificially using physical mutagens like X-rays and gamma rays, or chemical mutagens like EMS (ethyl methanesulfonate). The advantage of mutation breeding is that it can create entirely new genetic variations and traits that may not exist in the available germplasm. It is particularly the only viable method for improving seedless crops like bananas and grapes where conventional sexual reproduction is not possible. Mutation breeding has led to the development of several important crop varieties with improved yield, disease resistance, and quality traits, making it an indispensable tool in modern plant breeding programs.
The superiority of the FI hybrid in performance over its parents is called heterosis or hybird vigour.
* G.H. Shull was the first scientist to use the term heterosis in 1912.
* Heterosis are of the following types.
* Euheterosis, Mutational Euheterosis, Balanced Euheterosis and Pseudoheterosis
(i) Euheterosis:
This is the true heterrosis which is inherited and is further classified as.
(a) Mutational Euheteosis:
Simplest type of euheterosis and results from the sheltering or eliminating of the deleterious unfavourable often lethal, recessive, mutant genes by their adaptively superior dominant alleles in cross pollinated crops.
(b) Balanced Euheterosis:
well balanced gene combinations which is more adaptive to environmental conditions and agricultural usefulness.
(ii) Psuedohetrosis:
Also termed as luxuriance progeny possess superiority over parents in vegetative growth but not in yield and adaptation usually sterile or poorly fertile.
New Breeding Techniques (NBT) are a collection of methods that could increase and accelerate the development of new traits in plant breeding. These techniques often involve genome editing, to modify DNA at specific locations within the plants to produce new traits in crop plants. The various methods of achieving these changes in traits include the following.
* Cutting and modifying the genome during the repair process by tools like CRISPR /Cas.
* Genome editing to introduce changes in a few base pairs using a technique called Oligonucleotide-directed mutagenesis (ODM).
* Transferring a gene from an identical or closely related species (cisgenesis).
* Organizing processes that alter gene activity without altering the DNA itself (epigenetic methods)
12th Bio Botany Guide Plant Breeding Additional Important Questions and Answers
I. Match the Following
a) A & R are true.
c) A is True and R is Wrong
a) (A) is correct; (R) is wrong
d) A is Wrong and R is True
VI. Choose the Correct Statements
c) The genotype is unchanged for a long period of time. This is the primary disadvantage of pureline selection because it relies on selecting from existing genetic variation within a population rather than creating new genetic combinations. Since pureline selection involves continuous self-fertilization and selection of the best-performing plants, the genetic diversity decreases over generations and no new genotypes are created, making the population less adaptable to environmental fluctuations and limiting the scope for further improvement.
c) Drop in yield
a) Tomato
a) Maize
a) Rye
b) Atomita -2
d) Bacterial Inoculants
c) Arthropod
a) Tomato
c) Green leaf
c) (i) C; (ii) D; (iii) A; (iv) B
a) 1926
c) Wheat
d) Quarantine
a) Rangpuri
c) Mass Selection
b) Pure line
c) Beauveria
b) Vegetative Propagation
d) Pseudo heterosis
a) Mutation Breeding
c) seedless
d) Gamma garden
d) Natural selection
a) Third
a) Nel jeyaraman
d) Biofortification
c) maize stem borer
c) Clostridium
IX. Fill in the blanks.
1. De candolle in his ……………. studied 247 caltivated plants.
Origen of cultivated plants
2. Bamboo eas demesticated by ……………….
China
3. He was an eminet Sorghum breeder,devoloped World’s first hybrid of Sorghum CSH-1.
N.G.P.Rao.
4. ……………… is used as a biofertilizer for wetland rice cultivation
Azolla.
5. Vavilov in the year ………………. converted 8 main geographic centres of origin to 12
1935
6. Harlan says that the centre of crop plants means the places of ……………… origin of the crop plants.
Agricultural
7. The ……………… was domesticate only in the Chiloe centre
Potato
8. ………………. could be also called as Bioinoculants
Biofertilizers
9. C.T.Patel devoloped World’s first …………….. hybrid
Cotton
10. Choudhary ram dhan made …………….. as punjab granary of India.
Wheat
11. Azdla is used as biofertiliser for wetland rice cultivation and is known to contribute ……………./ha/crop.
40-60 kg
12. …………….. is Associated with Phycomycetous fungi and angiosperm roots.
Arbuscular Mycorhizzoe
13. ……………… contains Auxin,Cytokinin and Gibberellins
Seaweed liquid fertiliser
14. ……………… species are free living fungi that are common in soil and root ecosystem
Trichoderma
15. Damping of tomato is caused by ……………..
Rhizoctonia Solani
16. It is one of the most important green manure crops
Tephrosia Purpurea
17. The double helix structure of DNA was identified by ……………. and …………….
James Watson,Francis Crick
18. By 2050 we will …………….. need more food to feed the rapid growing population.
50%
19. Crop domestication started early during ……………….
10,000 Bc
20. ………………. Corn was developed using targetted breeding.
Waxy
21. Rice variety of ……………. introduced from Philippines
IR8
22. NBPGR is located in Chennai at …………………..
Meenembakkan
23. Introduced plants get adapted to the new environment is called as ……………….
Acclimatization
24. Tea varieties collected from China and North East India initially grown in Botanical garden of ……………….
Kolkatta
Selection
25. ______ is the oldest and basic method of plant breeding
Preliminary
26. In clonal selection …………… yield trial takes place during 3rd year.
Intrageneric
27. Interspecific hybridization is also called as _____
hybridization
28. Green revolution scheme began in ……………. in 1940’s.
Mexico
29. In 2005 …………….. organized a first ever traditional paddy seed festival in his farm as an individual.
Nel jayaraman
30. …………… is a cleaving protein.
Cas9
X. Two Marks
Economic Botany is the branch of botany that studies the relationship between people and economically important plants. It encompasses the study of plants that have direct economic value and practical applications for human welfare, including food crops, medicinal plants, fiber-producing plants, timber trees, ornamental plants, and plants used in various industries. Economic Botany examines how humans utilize plants for food, medicine, clothing, shelter, fuel, and other purposes, as well as how plant cultivation and management practices affect human societies and economies.
Archeological evidence for earliest record of agriculture is found in the fertile crescent region in and around Tigris and Euphrates river valleys, approximate about 12,000 years
ago
- He studied 247 cultivated plant species.
- He attempted to solve the mystery about the anscestral form, region of domestication and history.
- Initially he proposed eight main geographic centres of origin.
- Later by dividing few centres into two or three centres and added a new centre USA.
- Thus making the 8 centres of Origin into 12.
- It is defined as preparations containing living cells of efficient strains of micro organisms that help in crop yield.
- It contains Cytokinin, Gibberellins, and auxin a part from macro & micro nutrients.
- It has Alginates, Carbohydrate, 70 types of minerals, Vitaming and enzymes.
- It control plant diseases
- Ability to enhance root growth.
- Increases crop productivity.
- Provides resistance to abiotic stress.
- Helps in uptake and use of nutrients.
- Introduction of genotypes from a place where it is normally grown to a new place.
- eg. IR & Rice from Philippines.
- The adjustment or adaptation of the introduced plant in the changed environment is called acclimatization.
- All the introduced Crop must be free from presence of weeds, insects and disease causing Organisms.
- It has to be carefully examined by the process called quarantine.
- A strict isolation imposed to prevent the spread of disease.
- This is a rule in the nature.
- It results in evolution reflected in the Darwinian’s principle survival of the fittest.
- It takes longer time to bring about desired Variation.
- It is a human involved process.
- Having better crop from a mixed population.
- The individuals differ in character.
The three types of artificial selection are mass selection, pureline selection, and clonal selection. Mass selection involves selecting superior individuals from a mixed population based on their phenotype and allowing them to interbreed, which is effective for cross-pollinated crops. Pureline selection involves repeated self-pollination from a single homozygous individual to obtain a pure line with uniform characteristics. Clonal selection is employed to select improved varieties from a mixed population through asexual propagation, where all plants in the clone are genetically identical to the parent plant.
- It is a process of removal of anthers to prevent self pollination before the opening of a flower.
- Physical Mutagen – UV short wave, X-ray, Alpha, Beta and Gamma Waves.
- Chemical Mutagen – Cesium, Ethylmethane sulfonate Nitromethyl and Urea.
- It is a form of mutation breeding.
- The Radioactive sources are cobalt – 60 and Caesium -137
- The first Gamma Garden in India is Bose Research institute at Calcutta.
- It often exhibit increase hybrid vigour.
- Increase the tolerance to both biotic and abiotic stresses
- Polyploidy can be induced by the use of cochicine to double the chromosome number.
- Seedless Tomato, Apple, Watermelon and orange.
- It is the cumulative result of a series of research, development, innovation and technology transfer initiatives in Agriculture.
- He is the pioneer mutation breeder.
- He has produce sharbati Sonora is the amber grain coloured variety of wheat.
- He is responsible for green revolution in India.
The objectives considered in breeding to improve the nutritional quality of plants include increasing the protein content and quality, enhancing oil content and composition, improving vitamin content and bioavailability, increasing micronutrient levels such as iron and zinc, and enhancing mineral content. These improvements aim to make crops more nutritionally valuable for human consumption and to address nutritional deficiencies in populations that depend on these crops as staple foods. Such breeding programs are particularly important for developing countries where malnutrition is a concern.
Crop
Variety
Insect pests
Brasica (rapeseed mustard)
Flat been
Okra (Bhindi)
Pusa Gaurav
Pusa Sem 2, Pusa Sem 3
Pusa Sawani, Pusa A
Aphids
Jassids, aphids and fruit borer
Shoot and Fruit borer
- CRISPR – Clustered Regularly Interspaced short Palindromic Repeats
- ODM – Oligonucleotide – Directed Mutagenesis.
Tissue culture is considered a highly effective method for artificial vegetative reproduction in plants, especially for large-scale propagation. The primary advantage of tissue culture lies in its ability to produce a large number of genetically uniform clones from a small piece of plant tissue, known as an explant, cultured in vitro under sterile conditions. This technique allows for the rapid multiplication of desirable genotypes, which is particularly beneficial for both crop species and tree species used in forestry. By utilizing tissue culture, plants with specific advantageous characteristics can be produced in significant quantities within a relatively short period, contributing to efficient breeding programs and conservation efforts.
- Azolla is a free floating water fern that fixes atmospheric nitrogen in association with nitrogen fixing blue green algae. Anabaena azolla.
- It is used as a bio-fertilizer for wetland rice cultivation and is known to contribute 40-60 kh/hal/crop.
- Cassia fistula
- Sesbania grandiflora
- Azadirachta indica
Bio-pesticides are biologically based agents or preparations used for the control of plant pests and diseases. They are derived from living organisms or their byproducts and are environmentally friendly alternatives to synthetic chemical pesticides. A common example of bio-pesticide is Trichoderma, a fungus that acts as a biocontrol agent against various plant pathogens and pests. Other examples include Bacillus thuringiensis (Bt), which produces toxins lethal to insect larvae, and various entomopathogenic fungi and bacteria. Bio-pesticides are safer for the environment, non-toxic to humans and beneficial organisms, and help maintain ecological balance in agricultural systems.
Biofertilizers and green manuring are two distinct approaches to improving soil fertility and crop nutrition. Biofertilizers are preparations containing living or latent cells of efficient strains of microorganisms such as nitrogen-fixing bacteria, phosphate-solubilizing bacteria, or mycorrhizal fungi. When applied through seed or soil, biofertilizers enhance the crop's uptake of nutrients from the soil and improve soil fertility in an ecofriendly manner. Green manuring, on the other hand, involves the growing of green manure crops such as legumes and their incorporation directly into the field by ploughing. Green manuring helps increase the nitrogen content in the soil through biological nitrogen fixation and improves the structure and physical properties of the soil by adding organic matter. While biofertilizers work by enhancing nutrient availability and uptake, green manuring works by adding organic matter and fixing atmospheric nitrogen into the soil.
Pureline selection and clonal selection are two different methods of selecting improved plant varieties. Pureline selection is a collection of plants obtained as a result of repeated self-pollination from a single homozygous individual. The progeny shows increased homozygosity with respect to all genes, meaning the plants become progressively more uniform and pure for all traits. This method is effective for self-pollinated crops and results in stable, uniform varieties. Clonal selection, on the other hand, involves asexual propagation and is employed to select improved varieties from a mixed population. The progeny resemble the parent plant in genetic constitution because they are produced through mitotic division, making them genetically identical clones. Clonal selection is particularly useful for vegetatively propagated crops and for maintaining desirable traits that might be lost through sexual reproduction.
Mutation breeding and polyploid breeding are two distinct approaches to creating genetic variation and improving crop varieties. Mutation breeding involves inducing or selecting sudden heritable changes in the genotype or phenotype of organisms through exposure to mutagens such as radiation or chemicals, or by identifying naturally occurring mutations. These mutations provide new genetic variation that can be selected for desirable traits. Polyploid breeding involves working with plants that possess more than two sets of chromosomes, known as polyploids. Polyploidy is of considerable importance in plant breeding as it provides essential genetic inputs for evolution, recombination, and selection. Polyploid plants often exhibit increased hybrid vigour, increased heterozygosity, and enhanced vigor compared to their diploid counterparts. Polyploidy can occur naturally or be induced artificially through chemical treatment with colchicine. Both mutation and polyploid breeding are valuable tools for generating genetic diversity and developing improved crop varieties with desirable characteristics.
Intervarietal hybridization and interspecific hybridization are two different types of crosses used in plant breeding programs. Intervarietal hybridization involves crossing plants of two different varieties within the same species. This technique has been the basis of improving both self-pollinated and cross-pollinated crops by combining desirable traits from different varieties. Interspecific hybridization, on the other hand, involves crossing plants of two different species. This technique is commonly used for transferring beneficial genes from one species to another, particularly when transferring disease resistance, pest resistance, or other desirable traits from wild relatives or related species into cultivated crops. Interspecific hybrids may face fertility problems due to chromosomal incompatibility, but when fertile hybrids are obtained, they can provide access to a much broader genetic base for crop improvement.
- Agronomy, Anthropology, Archaeology, Chemistry, trade and commerce.
- It is the process of bringing a plant species under the control of humans and gradually changing it through careful selection.
- It is as alternative agricultural system.
- It is due to rapidly changing farming practices.
- It is a production system that sustains the health of the soils, ecosystems and people.
- It is based on ecological processes biodiversity and cycles adapted to local conditions
- It is an entomo-pathogenic fungi
- It acts as a parasite on various arthropod that causes white muscardine disease.
- It also controls datnping off of tomato caused by Rhizoctonia Solani.
- Plant breeding is the science of improvement of crop varities with higher yield better quality, resistance to diseases and shorter durations which are suitable to particular environment.
The Green Revolution, also known as the third Agricultural Revolution, was an intensive plan initiated in the 1960s aimed at increasing crop yield in developing countries. The plan involved introducing high-yielding, disease-resistant and pest-resistant varieties of crops, particularly cereals like wheat and rice. It also included increased irrigation facilities to ensure adequate water supply, enhanced fertilizer application to boost nutrient availability, and better agricultural management practices including improved farming techniques and pest control methods. The Green Revolution significantly increased food production and helped many developing countries achieve food security. However, it also led to increased use of chemical inputs, which raised concerns about environmental sustainability and long-term soil health.
The main steps involved in plant breeding are identification of objective and selection of parents, hybridization of selected parents to create genetic variation, selection and evaluation of superior plants from the segregating generations, testing of selected lines for their performance across different environments and seasons, and finally release and commercialization of the improved variety. The process begins with clearly defining the breeding objective, such as improving yield, disease resistance, or nutritional quality. Parents with complementary traits are then selected and crossed to combine desirable characteristics. The resulting progeny are carefully evaluated over multiple generations, with superior plants being selected based on the desired traits. These selected lines are tested under various environmental conditions to ensure stability and consistency of performance. Once a variety proves superior and stable, it is released for commercial cultivation.
- It is responsible for introduction and maintence of germplasm of various agricultural and horticultural station in our country.
- It is also responsible for maintenance of plant materials of botanical and medicinal interest.
- It is located at Rangpuri/New Delhi with four regional station at Amristar, Kolkata, Mumbai and Chennai.
- Hybridization is the method of producing new crop verities by crossing of plants that are genetically different.
- It offers improvement in crop by combining the desirable character of two or more varities.
- The first natural hybridization was observed by Cotton Mather in maize.
- It is called as pseudoheterosis because the progeny is superior over parents by vegetative growth.
- They are usually sterile.
- It is also called as Luxuriance.
Several crop varieties have been developed with resistance to specific diseases through selective breeding programs. Wheat variety Himgiri is resistant to leaf rust, stripe rust, and hill bunt. Brassica variety Pusa Swarnim, also known as Kara rai, is resistant to white rust. Cauliflower varieties Pusa Shubhra and Pusa Snowball K-1 are resistant to black rot and curl blight. Cowpea variety Pusa Komal is resistant to bacterial blight. Chilli variety Pusa Sadabahar is resistant to chilly mosaic virus, tobacco mosaic virus, and leaf curl. These disease-resistant varieties reduce crop losses, decrease the need for chemical fungicides and bactericides, lower production costs, and promote sustainable agricultural practices. The development of such varieties involves identifying disease resistance genes in germplasm collections and incorporating them into high-yielding cultivars through conventional breeding or modern biotechnological approaches.
- Genetic Engineering, plant tissue culture, protoplasmic fusion, Molecular marking and DNA finger printing.
Mutation breeding is a plant breeding technique that involves inducing or selecting sudden heritable changes in the genotype or phenotype of an organism. These changes, called mutations, can occur naturally or be induced artificially through exposure to physical mutagens such as X-rays, gamma rays, or neutron radiation, or chemical mutagens such as ethyl methanesulfonate (EMS). Mutations provide new genetic variation that can be screened and selected for desirable traits such as improved yield, disease resistance, or nutritional quality. Once a desirable mutant is identified, it can be propagated and developed into a new variety. Mutation breeding has been successfully used to develop several important crop varieties and is particularly useful when natural genetic variation for a desired trait is limited or unavailable in the existing germplasm.
Bio-fortification is the process of breeding and developing crop varieties with higher levels of vitamins, minerals, proteins, and healthier fats through selective breeding techniques. This approach represents the most practical and sustainable means to improve public health and nutritional status, particularly in populations that rely heavily on staple crops. By enhancing the nutritional content of commonly consumed food plants, bio-fortification addresses micronutrient deficiencies without requiring changes in dietary habits or the need for supplementation programs.
Sugarcane cultivation in India involves two primary species with distinct characteristics. Saccharum barberi, originally grown in North India, is characterized by its relatively poor sugar content and lower yield. In contrast, Saccharum officinarum, a tropical cane cultivated in South India, possesses thicker stems and significantly higher sugar content. However, Saccharum officinarum does not grow well in the climatic conditions of North India. Recognizing these limitations, successful cross-breeding efforts have been undertaken between these two species. The aim of these crosses is to develop new sugarcane varieties that combine the desirable qualities of both parents: the high yield, thick stems, and high sugar content of the tropical cane, along with the adaptability to grow well in the sugar-producing regions of North India.
- Adaption to the environmental alteration.
- Adaption to wider geographical range.
- Uniformity in flowering and fruiting.
- Increased size of fruits and seeds.
- Change in breeding system.
- Increase in yield.
- Increased resistance for disease and pest.
- Developing seedless parthenocarpic fruit.
- Enhancing the taste and nutritional composition.
* 1807 – Alexander Yon Humboldt considered that original & source of most and their origin is an importable secret.
* 1868 – Darwin’s theory proposed that natural selection and hybridization led to the origin of cultivate plants.
* 1883 – De Candolle studied 247 cultivated plants species and was able to find the ancestral form, region of domestication and history.
* 1887-1943 – Vavilov studied about the diverse forms of plants based on various criteria like morphology,cytology etc., He proposed 8 geographic centres and later developed it to 12 centres.
* 1968 – Zhukovsky put forward the concept of mega gene and divided the whole world into 12 mega gene centres.
* 1971 – Harlen believed that agriculture originated independently in three different areas.
– There were non centres are the area were the crop has been shifted.
Vavilov’s centres of crop origin and crops domesticated.
Vavilov’s centre of crop origin
Crops domesticated
1. China
Foxtail millet, soybean, bamboo, onion,.crucifers
2. India
Rice, Sugarcane, mango, orange, eggplant, sesame
2a. South East Asia
Rice, banana, coconut, clove, hemp.
3. Central East
Wheat, pea, hemp, cotton, etc.,
4. The Near East
Wheat, rye, many subtropical and tropical fruits
5. Mediterranean
Olive, vegetables, oil, yielding plants, wheats
6. Ethiopia (Abyssinian)
Wheat, barley, sesame, castor, coffee
7. Mesomerica (South Mexican & central American centre)
Maize, bean, sweet potato, papaya, guava,
tobacco
8. South America
Tomato, pine-apple
8a. South America
Potato
8b. The Brazilian-Paraguayan centre
Groundnut, cashew nut, pine apple, peppers, rubber.
India has a rich history of distinguished plant breeders who have made significant contributions to improving crop varieties and enhancing agricultural productivity. Dr. M.S. Swaminathan is widely recognized as the father of the Green Revolution in India and a pioneer in mutation breeding, instrumental in developing high-yielding varieties. Sir T.S. Venkatraman was an eminent sugarcane breeder whose work significantly improved sugarcane cultivation. Dr. B.P. Pal played a crucial role in developing superior, disease-resistant varieties of wheat, contributing to food security. Dr. K. Ramiah is celebrated as an eminent Rice Breeder, focusing on improving rice production. N.G.P. Rao, an eminent sorghum breeder, developed the world's first hybrid of sorghum, CSH-1, revolutionizing sorghum cultivation. C.T. Patel is credited with developing the world's first cotton hybrid, marking a breakthrough in cotton breeding. Lastly, Choudhary Ram Dhan, a dedicated wheat breeder, developed the C-591 wheat variety, which was pivotal in transforming Punjab into the 'wheat granary of India'.
Bio-fertilizers could also be called as microbial cultures or bacteria) fertilizers.
* They are efficient in fixing nitrogen improve soil fertility, eco-friendly and cost effective.
Rhizobium:
* It resides in the root nodules of leguminous plants.
* It fixes the atmospheric Nitrogen.
* It increases yield of paddy by 15-40%
Azolla:
* Free floating water fern, with blue green algae fixes the Nitrogrn.
* It increases the yield of rice.
* It decomposes quickly.
Arbuscular Mycorrhizae:
* They can dissolve the phosphates found in the soil.
* It provides strength to resist disease, germ and unfavourable weather.
Seaweed Liquid Fertilizer:
* It contains cytokinin, gibberellins and Auxin
* Most of it are made from kelp ( Brown Algae).
* The alginates in it react with metals in soil and retain moisture for a long time.
* They have more than 70 minerals vitamin and enzymes.
* Seeds soaked in seaweed germinate rapidly.
They are biologically based agents used for the control of plant pests.
* They are ecofriendly, Non – toxic and cheaper the chemical pesticide.
Trichoderma:
* They are free living fungi in the soil.
* They control plant disease.
* It has the ability to enhance root growth development.
* Increases the crop productivity.
* It helps in resisting Abiotic stress.
* It increases the uptake and use of nutrients.
Beauveria:
* It is an entomo – pathogenic fungus
* It parasitse arthropods that cause white muscardine and controls damping off of tomato
- To increase yield, Vigour and fertility of the crop.
- To increase tolerance to environmental condition, Salinity, Temperature and drought.
- To prevent premature falling of buds fruits etc.,
- To improve the maturation of both the male and female gametes at the same time.
- To develop resistance to pathogens and pests.
- To develop photosensitive and thermos – Sensitive Varieties.
Selection is the oldest and basic method of plant breeding.
* There are two main types of selection – Natural and Artificial.
Natural Selection:
* It occurs naturally.
* It takes longer time in bringing about desired variation.
* It reflected the Darwinian principle.
Artificial Selection:
* It is a human involved process.
* Producing better crop from a mixed population.
a) Mass Selection:
* Large number of plants of similar phenotype are selected and crossed to get a new variety.
* After repeated selection for five to six years it is distributed to the farmers.
b) Pureline Selection:
* Plants obtained as a result of self pollination from a single homozygous individual.
* The progeny shows homozy gosity with respect to all genes.
* New Genotypes are never created,
c) Clonal Seection:
* The progenies that are asexually propagated resembles the parent genetically.
* The progeny is multiplied to form clone.
* The genotype of a clone remains unchanged for a long period of time.
Hybridization involves several key steps to create new plant varieties with desired traits. First, 'Selection of Parents' involves identifying male and female plants possessing the specific desirable characters, and these parents must be tested for homozygosity to ensure predictable inheritance. Second, 'Emasculation' is the removal of anthers from the bisexual flower before they mature and shed pollen, which is crucial to prevent self-pollination. Third, 'Bagging' is done to cover the stigma of the emasculated flower with a suitable bag to protect it from any foreign, undesirable pollen grains. Fourth, 'Crossing' involves the artificial transfer of pollen grains from the selected male flower to the stigma of the emasculated female flower. Finally, 'Harvesting Seeds and Raising Plants' involves collecting the seeds that develop after successful fertilization and sowing them to grow the new generation of hybrid plants.
Heterosis, or hybrid vigor, refers to the phenomenon where the hybrid progeny exhibits superior performance compared to its parents. It can be categorized into several types. 'Euheterosis' is considered true heterosis, where the superiority is heritable and stable. 'Mutational Euheterosis' is a simpler form where superior dominant alleles mask the effect of harmful recessive mutant genes, particularly observed in cross-pollinated crops. 'Balanced Euheterosis' occurs when a well-balanced combination of genes results in progeny that are highly adaptive to the environment and possess significant agricultural usefulness. 'Pseudo heterosis', also known as luxuriance, is a type where the progeny show superiority over parents in vegetative growth but not necessarily in yield or adaptation, and these hybrids are often sterile or poorly fertile.
- The plants which posses more than two sets of chromosomes are called Polyploids.
- It is the major force in the evolution of both wild and cultivated plants.
- Polyploid of exhibit hybrid vigour.
- Increases tolerance to biotic and abiotic stresses.
- Polyploidy results in reduced fertility and producing seedless varieties.
- If chromosomes is doubled by itself it is autopolyploidy.
- Triploid condition in Sugarbeets result in Vigour.
- Colchicine used to double the chromosomes. Eg. Triticale and Raphanobrassica
Biofortification is a crucial strategy in plant breeding aimed at enhancing the nutritional value of crops, thereby addressing micronutrient deficiencies in populations. This involves breeding crops to have higher levels of essential nutrients such as proteins, vitamins, and minerals. For instance, efforts have led to the development of maize hybrids with double the nutrient value compared to their parents. Wheat varieties like 'Atlas 66' have been bred for high protein content. Furthermore, research has enabled the development of iron-fortified rice, vitamin A-enriched vegetables, and crops enriched with vitamin C, iron, and calcium, making staple foods a more effective source of essential nutrients.
- It is a collection of methods that could increase the development of new traits in plant breeding.
- It often involve genome editing.
- Cutting and modifying the genome during the repair process by tools like CRISPR.
- Genome editing to introduce changes in few base pairs using a technique called ODM.
- Transferring a gene from an identical or closely related species (Cisgenesis)
- Organising process that alter gene activity without altering the DNA itself.
(i) Somu will get the new variety. Because he had selected the mixed population method.
(ii) Advantages of self fertilization method:
The repeated self pollination from a single homozygous individual produces a variety that shows more homozygosity with respect to all genes.
(iii) Dis advantages:
* The major disadvantage of this type is that it never creates new genotypes.
* The plants produced are also less adaptible and less stable to the environmental fluctuations.
Advantages of Mixed population method
In this method, a large number of plants of similar phenotype (or) morphological characters are selected and their seeds are mixed together to constitute a newer variety’.
Disadvantages:
The disadvantage of mixed population method is that it is difficult to distinguish the hereditary variation from environmental variation.
- Prevents spread of plant disease
- Protects seed from seedling blights
- Improves germination
- Improves germination
- provides protection from storage insects
- controls soil insects.