TS Inter 2nd Year Botany Study Material Chapter 13 Strategies for Enhancement in Food Production

Telangana TSBIE TS Inter 2nd Year Botany Study Material 13th Lesson Strategies for Enhancement in Food Production Textbook Questions and Answers.

TS Inter 2nd Year Botany Study Material 13th Lesson Strategies for Enhancement in Food Production

Very Short Answer Type Questions

Question 1.
What is meant by ‘hidden hunger’?
Answer:

1. About 3 billion people over the globe are suffering from deficiencies of micro nutrients, protein and vitamins. This situation is said to be ‘Hidden hunger’.
2. More than 840 million people in the world do not have adequate food to meet their daily food and nutritional requirements.

Question 2.
Name two semi-dwarf varieties of rice developed in India. [Mar. 2020]
Answer:

1. Jaya and Ratna, are two better yielding semi – dwarf varieties of rice developed in India.
2. They are derivatives of semi – dwarf varieties derived from crossing IR – 8 with TN – 1.

Question 3.
Give two examples of wheat varieties introduced in India, which are high yielding and disease resistant. [March 2018]
Answer:

1. Sonalika and Kalyan Sona,
2. They were introduced in 1963, all over the wheat growing belt in India.

Question 4.
Give two examples of fungi used in SCP production. [March 2019, Mar. ’17; May ’17]
Answer:

1. Candida utilis (Torula yeast)
2. Saccharomyces cerevisiae (Baker’s yeast)
3. Chaetomium cellulolyticum

Question 5.
Why are plants obtained by protoplast fusion called somatic hybrids?
Answer:

1. Isolated protoplast from two different varieties of plants each having a desirable character- can be fused to get hybrid protoplasts which can be further cultured to form a novel plant.
2. Hybrid derives from fusion of vegetative (somatic) or body cells unlike that of fusion of sex cells is called somatic hybrid.

Question 6.
What is protoplast fusion?
Answer:

1. Nacked plant cells produced by digesting cell walls using cellulose and pectinose are called protoplasts.
2. The fusion of isolated protoplast from two different varieties of plants is called protoplast fusion.

Question 7.
Why is it easier to culture meristems compared to permanent tissues’?
Answer:

1. Meristems are undifferentiated, embryonal living plant cells which have the capacity of cell divisions and hence easy to culture.
2. Permanent tissues consists of differentiated cells that have to undergo dedifferentiation to undergo cell division and hence difficult to culture.

Question 8.
Why are protein synthesized from Spirulina called single cell proteins?
Answer:

1. Spirulina is a unicellular alga and is rich source of protein.
2. Dried biomass of a single species of microbe used as a protein source in the diet is •known as Single Cell Protein.

Question 9.
A person who is allergic to pulses are advised to take a capsule of Spirulina dialy. Give reasons for the advice. [May 2014]
Answer:
Pulses contain proteins, Similarly Spirulina also contains proteins. So if a person is allergic to pulses he can take Spirulina for proteins.

Question 10.
Would it be wrong to refer to plants obtained through micro propagation as ‘Clones’? Explain.
Answer:

1. No, since the formation of plants through micro propogation does not involve fusion of sex cells from two parents, they can be called as Clones.
2. The plants produced by Micropropagation are genetically identical to the origin or source plant and hence they are called Somaclones.

Question 11.
How is somatic hybrid different from a hybrid?
Answer:

1. Two different plants of desired characters are crossed to form a hybrid. It is a product of sexual reproduction.
2. Isolated protoplasts from vegetative cells of two different plants, each having a desirable character – can be fused to get hybrid, protoplast, and is cultured to form somatic hybrid.

Question 12.
What is emasculation? Why and when is it done?
Answer:

1. Removal of anthers from bisexual flowers of female parent, when the flowers are still in bud condition is called emasculation.
2. It prevents self-pollination and ensures artificial cross pollination.

Question 13.
Discuss the two main limitations of plant hybridization programme.
Answer:

1. It is not necessary that the hybrids do combine the desirable characters. Usually only one in a few hundred to a thousand crosses show the desirable combination.
2. Selection of superior recombinants and subjecting them to self pollination to achieve homozygosity so that the characters will not segregate in the progeny.

Question 14.
Give two important contributions of Dr. M.S. Swaminathan.
Answer:

1. Swaminathan and his team developed short duration high-yielding varieties of Rice including scented Basmati.
2. He introduced Mexican varieties of wheat in India.

Question 15.
Which two species of sugarcane were crossed for better yield?
Answer:

1. Saccharum barberi of North India had poor sugar content and Saccharum officinarum of South India had higher sugar content were crossed to produce a new varety with desirable qualities.
2. New variety has high yield, thick stems, high sugar and grow well in North India.

Short Answer Type Questions

Question 1.
What is meant by germplasm collection? What are its benefits?
Answer:
The entire collection of plants / seeds, having all the diverse alleles for all genes in a given crop is called germplasm collection.

1. Cell and tissue cultures of many plant species can be preserved maintained in a viable state for several years and used when required.
2. Plant materials from endangered species can be conserved using this method.
3. It is an ideal method for long term conservation of cell cultures producing secondary metabolites such as antibiotics.
4. Seeds which loose their viability or storage can be maintained for a long period of time.
5. Disease free plant material can be frozen and propagated whenever required.
6. Conservation of Somaclonal variations in cultures.
7. Rare germplasms developed by using Somatic hybridisation other genetic manipulation techniques can be stored.
8. Pollen conservation for enhancing longevity.
9. Germplasm banks to facilitate the exchange of information of international level.

Question 2.
Name the improved characteristics of wheat that helped India to achieve green revolution.
Answer:

1. Green revolution is the dramatic increase in food production due to plant breeding „ techniques.
2. During the period 1960 to 2000, wheat production increased from 11 million tonnes to 75 million tonnes this is due to development semi-dwarf variety of wheat.
3. Semi-dwarf wheat was developed by Norman E.Borlaug at International Centre for Wheat and Maize improvement in Mexico.
4. In 1963, several varieties such as Sonalika and Kalyan Sona which were high yielding and disease resistant, were introduced all over the wheat growing belt of India.

Question 3.
Suggest some of the features of plants that prevent insect and pest infestation.
Answer:

1. Major cause for large scale destruction of crop plant and crop produce is insect and pest infestation.
2. Insect resistance in host crop plants may be due to morphological, biochemical or physiological characteristics.
3. Hairy leaves in several plants are associated with resistance to insect pests, e.g.: resistance to jassids in cotton and cereal leaf beetle in vyheat.
4. In wheat, solid stems lead to non-preference by the stem sawfly.
5. Smooth leaved and nectar-less cotton varieties do not attract bollworms.
6. High aspartic acid, low nitrogen and sugar content in maize leads to resistance to maize stem borers.

Crop	Variety	Insect Pests
Brassica (rapeseed, mustard)	Pusa Gaurav	Aphids
Flat bean	Pusa Sem 2, Pusa Sem 3	Jassids, aphids and fruit borer.
Okra (Bhindi) (Lady’s Finger)	Pusa Sawani	Shoot and Fruit borer Pusa A-4

Question 4.
The culture medium (nutrient medium) can be referred to as a ‘highly enriched laboratory soil’. Justify the statement.
Answer:
Culture medium must provide a carbon source such as sucrose and also in organic salts, vitamins, amino acids and growth regulators like auxins, cytokinins etc.

The culture medium is rich in nutrients.

Question 5.
Plants raised through tissue cultures are clones of the ‘parent’ plant.’ Discuss the utility of these plants.
Answer:

1. Plants produced through tissue culture are genetically identical to the original or source plant and hence they are called somaclones.
2. Many economically important plants like tomato, banana, apple, teak, eucalyptus, bamboo etc. have been produced on a commercial scale by the use of this method.
3. Recovery of healthy plants from diseased plants can be done.
4. One can remove the meristem and growin in vitro to obtain virus free plants.
5. Scientists have succeeded in culturing meristems of banana, sugarcane, potato etc.

Question 6.
Discuss the importance of testing of new plant varieties in a geographically vast country like India.
Answer:

1. The newly selected lines are evaluated for their yield and other agronomic traits of quality, disease resistance etc.
2. This evaluation is done by growing these in research fields and recording their performance under ideal fertiliser application, irrigation and other crop management practices.
3. The evaluation in research fields is followed by testing the materials in farmer’s fields, for at least three growing seasons at several locations in the country, representing all the agroclimatic zones where the crop is usually grown.
4. The material is evaluated in comparison to the best available local crop cultivar-a check or reference cultivar.

Question 7.
Give few examples of biofortified crops. What benefits do they offer to the society?
Answer:
Biofortified crops are with higher levels of vitamins and minerals, or higher protein and healthier fats. It is the most practical means to improve public health of the society.

Examples of fortified crops :

1. Atlas 66 used as a donor for developing wheat varieties with improved protein content.
2. Maize hybrids have increased amount of aminoacid lysine and tryptophan.
3. Iron fortified rice have increased iron content.
4. India Agricultural Research Institute, New Delhi have released some fortified crop

varieties:
a) Carrot, spinach and pumpkin – Vitamin A
b) Bitter gourd, bathua, mustard, tomato – Vitamin C
c) Spinach and bathua – Iron and Calcium.
d) Broad bean, lablab, fresh bean and garden pea – Protein.

Question 8.
Mutations are beneficial for plant breeding. Taking an example, justify the statement.
Answer:

1. Mutations is defined as sudden heritable change in the character of an organism, due to change in the sequence of bases of the gene.
2. Few mutations may create numerous new varieties of economic value.
3. Due to mutation breeding the farmers need not depend on nature for variation.
4. It is possible to induce mutation artificially through the use of chemicals or radiations (like gamma radiations) and selecting and using the plants that have a desirable character as a source in breeding. This is called mutation breeding.
   Eg: In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.

Question 9.
Discuss briefly the technology that made us self-sufficient in food production.
Answer:

• Technology called Tissue Culture made us self sufficient in food production.
• By applying this technology, it is possible to produce a large number of plants in a very short time and limited space. Hence this technique is called micro propagation.
• Plants thus produced are genetically identical to the original or source plant and hence they are called somaclones.
• Many economically important plants like tomato, banana, apple, teak, eucalyptus, bamboo etc., have been produced on a commercial scale by the use of this method.
• Plant breeding as a technology has helped increased yield to a large extent. The green revolution was dependent on plant breeding techniques for developing high yielding and disease resistant varieties like rice, maize.
• Mutation breeding and rDNA technique also play important role in increasing food production.
• By mutation breeding, disease resistant crops were developed which prevented from large destruction.

Long Answer Type Questions

Question 1.
You are a Botanist working in the area of plant breeding. Describe the various steps that you will undertake to release a new variety. [Mar. ’18; May ’17, ’14]
Answer:
The steps in breeding a new genetic variety of a crop are

1. Collection of variability.
2. Evaluation and Selection of parents.
3. Cross hybridisation among selected parents.
4. Selection and testing of superior recombinants.
5. Testing, release and commercialization of new cultivars.

i) Collection of variability :

1. Genetic variability is important for any breeding programme.
2. Pre-existing genetic variability available in wild varieties, species and relatives of crop species is collected and preserved.
3. Evaluation of their characteristics is a pre-requisite for the effective exploitation of natural genes available in the population.
4. The entire collection of plants / seeds having all diverse alleles for all genes in a given crop is called germplasm collection.

ii) Evaluation and selection of parents :
a) It is carried out by evaluating germplasm to identify plants with desirable combination of characters.
b) The selected plant is multiplied and hybridized.
c) By self-pollination, purelines are created wherever desired.

iii) Cross hybridization among selected parents :

1. Cross hybridization is carried out to combine desired genetic characters from two different plants (parents).
2. Cross hybridization is a time consuming and tedious process as it involves collection of pollen grains from the desired plants and other pollination techniques to incorporate desired traits.
3. It is also not certain the hybrids combine desired characters. The chances of desirable combination is usually only one in few hundred to a thousand crosses carried out.

iv) Selection and testing of superior combinants :

1. This step consists of selection of plants among the progeny of the hybrids with desired combination of characters.
2. It yields plants that are superior to both of the parents. This is known as hybrid vigour / heterosis.
3. They are self pollinated for several generations till they reach a state of uniformity or homozygosity so that characters will not segregate in the progeny.

v. Testing, release and commercialization of new cultivars :

1. Evaluation is done for newly selected lines for their yield and other agronomic traits of quality, disease resistance etc.
2. Selected plants are grown in research fields and their performance is recorded under ideal fertilizer application irrigation and other crop management practices.
3. Testing of hybrid line is done in farmer’s field after evaluation.
4. After testing, the crop is grown at different locations in the country with different agroclimatic zones for at least three growing seasons.
5. The tested material is evaluated in comparison to the best available local crop cultivar used as reference cultivar.
6. Release of tested material is done in bulk after selection and certification.

Question 2.
Describe the tissue culture technique and what are the advantages of tissue culture over conventional method of plant breeding in crop improvement programmes? [Mar. 2020, 2019, 17, 14]
Answer:
The technique of growing, culturing and maintaining plant cells, tissues and organs in vitro is called tissue culture. Tissue culture is done by following methods :
1) Preparation of nutrient culture medium :
The nutrient medium must provide a carbon source such as sucrose and also inorganic salts, vitamins, amino acids and growth regulators like auxins, cytokinins etc.

2) Sterilization of the culture medium :

1. The medium is rich in nutrients and therefore, attracts the growth of microorganisms. The medium should be sterilized.
2. Sterilization is carried out in a steam sterilizer called autoclave.
3. The culture medium is autoclaved for 15 min, at 121°C and 15 lbs pounds of pressure.

3) Preparation of explant:
Any part of the plant body which is used as inoculum is called explant.

4) Inoculation of explants :
The transfer of explants on to the sterilized nutrient culture medium is called inoculation and is carried out in an aseptic condition.

5) Incubation of growth :

1. The cultures are incubated for 3 to 4 weeks during which period the cells of the explant absorb the nutrients, grow and undergo repeated divisions to produce undifferentiated mass of cells known as Callus.
2. Sometimes sheets or roots may be produced directly. ,
3. The explants or callus cultured on different combinations of auxins and cytokinins will produce shoots or roots and this process is called organogenesis.
4. Alternately, embryo like structures develop from the callus and this phenomenon is known as somatic embryogenesis, the embryo-like structure which develop from the callus are called embryoids. Since these embryoids develop from somatic tissue they are also called Somatic embryos.

6) Acclimatization of plantlets and transfer to pots :
The plants generated through organogenesis (or) somatogenesis need to be acclimatized before they are transferred to pots.

Advantages of tissue culture :

1. More number of plants can be produced in a short time.
2. Disease free plants can be developed from diseased plants.
3. Seedless plants can be multiplied.
4. Female plants are selectively produced through tissue culture.
5. Somatic hybrids can be raised by tissue culture, where sexual hybridization is not possible.

Flow chart showing Plant Tissue culture Technique

Question 3.
Modern methods of breeding plants can alleviate the global food ‘shortage’. Comment on the statement and give suitable examples.
Answer:
The development of several high yielding varieties of wheat and rice in the mid 1960’s as a result of various plant breeding techniques led to dramatic increase in food production in our country. This phase is often referred as green revolution.

High yielding and disease resistant varieties were introduced in India e.g. Sonalika and Kalyan Sona.

• Semi dwarf varities of rice e.g.: IR-8 Taichung Nalive -1 were introduced in 1966.
• Better yielding semi-dwarf varieties i.e., Jaya and Ratna were developed in India.

Successful developed high yield varieties of maizy jowar and bajra were obtained by hybrid breeding.

Plant breeding for disease resistance had enhance food production breeding is carried out by convention breeding techniques or by mutation breeding, e.g. In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.

Plant breeding for developing resistance to insect pests :
Major cause for large scale destruction of crop plant and crop produce is insect and pest infestation. Insect resistance in lost crop plants may be due to morphological, biochemical or physiological characteristics.

Examples:

1. Wheat – Hairy leaves – resistance to cereal leaf beetle
2. Maize – High aspartic acid and low nitrogen and sugar contents – resistance to stem borer
3. Wheat – Solid stem – resistance to sawfly
4. Cotton – Smooth leaves and nectar-less condition – resistance to bollworm
5. Cotton – Hairy leaves – resistance to. sawfly

Plant breeding for improved food quality :
Breeding crops with higher levels of vitamins and minerals or higher protein and healthier fats is called Biofortification. It is the practical means to improve public health.

Examples:

1. Lysine and tryptophan rich maize.
2. High protein rich wheat.
3. Iron fortified rice.
4. Vitamin enriched bitter gourd, tomato, mustard, bathua.
5. Iron and Calcium enriched spinach and bathua.
6. Vitamin A rich carrots, spinach and pumpkin.

Single Cell Protein :
Microbes are grown on an industrial scale and used as nutrient rich food. E.g.: Spirulina.

Tissue Culture:
Technique of regeneration of whole plant from any part of the plant by growing it on suitable culture medium under aseptic conditions in vitro.

Advantages:

1. 1) A number of plants can be grown in a short period of time, e.g.: Tomato, banana, apple, teak, eucalyptus etc.
2. Healthy disease free plant can be grown by meristem culture, e.g.: Banana, sugarcane, potato etc.
3. Somatic hybrid can be raised by tissue culture where sexual hybridisation is not possible.
   e.g.: Pomato

Question 4.
Discuss how the property of plant cell totipotency has been utilized for plant propagation and improvement.
Answer:
Totipotency of a cell can be defined as the capacity of a cell to generate into a whole plant.
Requirements:
i) Explant :
It is any part of a plant taken out for growing a new planfin special nutrient medium under sterile / aseptic conditions.

ii) Nutrient medium :
It must have a carbon source such as sugar, inorganic salts, vitamins, amino acids, growth regulators like auxins, cytokinins etc.

iii) Suitable conditions of light and temperature. This is a tissue culture method by which a number of genetically similar plants called somadones are grown.

Utilization for plant propagation and improvement:

1. By utilizing this property of totipotency thousands of plants can be grown in a short period. Hence this technique is called micropropagation.
2. Plants are genetically identical, so certain desirable characters can be continued through generations.
3. Many economically important plants like tomato, banana, apple, teak, eucalyptus, bamboo etc. have been produced on a commercial scale by the use of this method.
4. Meristem Culture : This method is useful in recovery of healthy plant from diseased plants. Although plant is infected with a virus, meristems are free of virus. One can remove the meristem and grow it in vitro to obtain virus free plants.
5. Scientists have succeeded in culturing meristems of banana, sugarcane, potato etc.
6. Plants are genetically identical, so certain desirable characters can be continued through generations.
7. Hybrids can be produced by hybridisation.
8. Somatic hybridization offer vast potential for manipulation of plants in vitro to produce new varieties, e.g.: Pomato

Question 5.
What are the three options to increase food production? Discuss each giving the salient features, merits and demerits.
Answer:
Mutation breeding, tissue culture and r DNA technique, are going to play a pivotal role in enhancing food production.

Salient features of mutations :

1. Mutation is a phenomenon which results in alteration of genes (= DNA sequence).
2. It results in changes in the genotype and the phenotype of an organism.
3. In addition to recombination, mutation is another phenomenon that leads to variation in DNA.
4. The process of breeding by artificially inducing mutations using chemicals or radiations.
5. Breeding for disease resistance is carried out by mutation breeding.

Merits:

1. Mutation generates a large amount of variability in a population.
2. Plant breeder can select the desirable types.
3. Improved varieties of crop plants with desirable characters can be obtained after careful selection & hybridization.

Demerits:
1) It results in changes in the genetic makeup which could be lethal and results in the death of an individual.

Tissue culture:

1. Tissue culture is a technique of regeneration of a whole plant from any part of a plant by growing it on culture medium under aseptic conditions.
2. The capacity of a cell explant to grow into whole plant is called totipotency.
3. Explant is the part of plant taken for tissue culture.
4. The method of growing or producing thousands of plants through tissue culture is called micropropagation.
5. The plants produced from tissue culture are genetically identical to the original plant from which they are grown, so they are called somaclones.

Merits:

1. More number of plants can be produced in a short time.
2. Disease free plants can be developed from diseased plant.
3. Seedless plants can be multiplied.

Demerits:

1. No new combinations of traits.
2. All the plants that are produced have the same genetic material. So they are equally vulnerable to environmental factors, infections and pests.

r DNA technology:

1. Genetic engineering is a laboratory technique of gene manipulation which brings about novel combination of genes.
2. Recombinant DNA technology enables us to isolate a gene of interest in an organism which can be inserted into a vector and make it express its native characteristics.

Merits:

1. r DNA technologies will play a key role in preventing genetic diseases.
2. It produces targeted medicines (like insulin for diabetic patients).
3. It will also impart agriculture to resists diseases.

Demerits:

1. Genetically modified plants spreading beyond control and driving out local species.
2. Expensive lab facilities.
3. Maintaining sterile environment.

Intext Question Answers

Question 1.
Describe in brief various steps involved in plant breeding.
Answer:
Plant breeding is the process in which two genetically dissimilar varieties are purposely crossed to produce a new hybrid variety. As a result, characteristics from both parents can be obtained in the hybrid plant variety. Thus it involves the production of a new variety with the desired characteristics such as resistance to diseases, climatic adaptability and better productivity. The various steps involved in plant breeding are as follows.

a) Collection of genetic variability :
Genetic variability from various wild relatives of the cultivated species are collected to maintain the genetic diversity of a species. The entire collection of the diverse alleles of a gene in a crop is called the germplasm collection.

b) Evaluation of germplasm and selection of parents :
The germplasm collected is then evaluated for the desirable genes. The selected plants with the desired genes are then used as parents in plant breeding parents in plant breeding experiments and are multiplied by the process of hybridization.

c) Cross-hybridization between selected parents :
The next step in plant breeding is to combine the desirable characters present in two different parents to produce hybrids. It is a tedious job as one has to ensure that the pollengrains collected from the male parent reach the stigma of the female parent.

d) Selection of superior hybrids :
The progenies of the hybrids having the desired characteristics are selected through scientific evaluation. The selected progenies are then self-pollinated for several generations to ensure homozygosity.

e) Testing, release and commercialization of new cultivers :
The selected progenies are evaluated for characters such as yield resistance to disease performance etc., by growing them in research fields for at least three growing seasons in different parts of the country. After thorough testing and evaluation, the selected varieties are given to the farmers for growing in fields for a large scale production.

Question 2.
What is meant by biofortification?
Answer:
Biofortification is a process of breeding crops with higher levels of vitamins, minerals, proteins and fat content. This method is employed to improve public health. Breeding of crops with improved nutritional quality is undertaken to improve the content of proteins, oil, vitamins, minerals and micro nutrients in crops. It is also undertaken to upgrade the quality of oil and proteins. An example of this is a wheat variety known as Atlas 66, which has high protein content in comparison to the existing wheat, in addition, there are several other improved varieties of crop plants such as rice, carrots, spinach etc. Which have more nutritious value and more nutrients than the existing varieties.

Question 3.
Which part of the plant is best suited for making virus-free plants and why?
Answer:
Apical and axillary meristems of plants is used for making virus-free plants in a diseased plant. Only this region is not infected by the virus as compared to the rest of the plant region. Hence the scientists remove axillary and apical meristems of the diseased plant and grow it in vitro to obtain a disease-free and healthy plant. Virus-free plants of banana, sugarcane and potato have been obtained using this method of scientists.

Question 4.
What is the major advantage of producing plants by micropropagation?
Answer:
Micropropagation is a method of producing new plants in a short duration using plant tissue culture. Some major advantages of micropropagation are as follows.
a) Micropropagation helps in the propagation of a large number of plants in a short span of time.
b) The plants produced are identical to the mother plant.
c) It leads to the production of healthier plantlets which exhibit better disease resisting powers.

Question 5.
Find out what are the various components of the medium used for propagation of an explant in vitro?
Answer:
The major components of medium used for propagation of explants in vitro are carbon sources such as sucrose, inorganic salts, vitamins, amino acids, water, agar-agar and certain growth hormones such as auxins and gibberellins.

Question 6.
Name any five hybrid varieties of crop plants which have been developed in India.
Answer:
The five hybrid varieties of crop plants which have been developed in India are

Crop plant	Hybrid variety
Wheat	Sonalika and Kalyan Sona
Rice	Jaya and Ratna
Cauliflower	Pusa Shubra and Pusa snowball K-1
Cowpea	Pusa komal
Mustard	Pusa swarnim (Karan rai)

Question 7.
The term ‘desirable trait’ can mean different things for different plants. Justify the statement with suitable examples.
Answer:
In case of rice, high yield and resistant to unfavourable conditions (like strom etc) is necessary. Hence the desirable trait is rice is high yield and resistant to unfavourable conditions. So semi-dwarf varieties are developed. In sugarcane desirable qualities are high yield, thick stem & high sugar. In wheat which are attached by rust the desirable trait in disease resistance. Similarly in case of lady finger plant insect resistance is a desirable character. This desirable traits are different for different plants.

Question 8.
Is there any relationship between dedifferentiation and higher degree of success achieved in plant tissue culture experiments?
Answer:
No, dedifferentiation occurs when a cell line is transformed, that means it becomes cancerous.

Question 9.
“Give me a living cell of any plant and I will give you a thousand plants of the same type”. Is this only a slogan or is it scientifically possible? Write your comments and justify them.
Answer:
It is not a slogan. It is possible scientifically by tissue culture techniques. The capacity to generate a whole plant from any cell is called totipotency. Large number of plants can be produced in a very short time and in limited space. Hence the technique is called Micro-propagation.

Question 10.
What are the physical barriers of a cell in the protoplast fusion experiment? How are the barriers overcome?
Answer:
The cell wall acts as a physical barrier of a cell in the protoplast fusion experiment. The barriers can be overcome by using hydrolyzing enzymes like cellulase and pectinase.