Topic-1
Animal Husbandry
Very Short Answer Type Question
Question. Mention the economic value of Apis indica.
Answer : Apis indica is a common species of honey bee used in apiculture. It is also useful in agriculture yield / honey / bee wax / pollination.
Question. Name any interspecific hybrid mammal.
Answer : Mule is an interspecific hybrid mammal. It is obtained by following cross : Female horse (Mare) × Male donkey.
Question. Write the name of the following :
(i) The most common species of bees suitable for apiculture.
(ii) An improved breed of chicken
Answer : (i) Apis indica / Apis mellifera / Apis dorsata
(ii) White Leghorn / Rhode Island Red / Minorca
Question. List any two economically important products for humans obtained from Apis indica.
Answer : (i) Honey (ii) Bee wax.
Question. Which one of the following is used in apiculture : Hilsa, Apis indica, Sonalika.
Answer : Apis indica.
Question. Suggest the breeding method most suitable for animals that are below average in milk productivity.
OR
Write professional approach at genetic level that can help the farmer to improve the milk yield of low milk producing cows on his farm.
Answer : Outcrossing or outbreeding or cross breeding is the most suitable breeding method for animal, that are below average in milk productivity.
Question. Mention the strategy used to increase homozygosity in cattle for desired traits.
Answer : Inbreeding increases homozygosity. It is the mating of related individuals of the same breed for 4-6 generations.
Question. Write the importance of MOET.
Answer : MOET (Multiple Ovulation Embryo Transfer) technology is a programme which is used
(i) to increase the herd size within a short time
(ii) to improve the chances of successful production of hybrids and
(iii) to obtain higher milk yielding cattle.
Short Answer Type Question – l
Question. What is outbreeding ? Mention any two ways it can be carried out.
Answer : Breeding of unrelated animals from the same breed having no common ancestors for 4 – 6 generations.
Outcrossing or cross breeding or interspecific hybridisation.
Question. What kind of areas are suitable for practicing apiculture? Write the scientific name of the variety commonly reared for the purpose.
Answer : Bee pastures of wild shrub, fruit orchards, cultivated crop. Apis indica
Question. A farmer maintained beehives in his Brassica field during its flowering season. How will he be benefitted?
OR
Keeping beehives in crop fields has several advantages. List any two.
OR
Why are beehives kept in crop field during flowering period ?
Answer : Keeping beehives in crop fields during flowering period increases pollination efficiency and improves the yield– crop yield and honey yield.
Question. In MOET technology, two ‘mothers‘ are needed to produce one calf. Justify.
Answer : One mother contributes fertilised eggs (8-32 cell stage), the other is surrogate.
Question. State the disadvantage of inbreeding among cattle. How it can be overcome ?
Answer : It leads to reduction in the fertility and productivity of an organism due to continuous inbreeding. This is also known as inbreeding depression. It can be overcome by outbreeding or out-crossing, in which mating is done between different selected unrelated superiors or individuals of the same breed having no common ancestors.
Question. (i) List two advantages of keeping beehives in a crop field during flowering season.
(ii) Name one annual and one perennial crop species favourable to beeswax collection.
Answer : (i) Bees help in increasing pollination efficiency, leading to improved yield.
(ii) Annual : Sunflower/Brassica or any other correct example.
Perennial : Apple / pear or any other correct example.
Question. Explain inbreeding depression and how it can be overcome.
OR
How does inbreeding depression set in ? Mention the procedure you would suggest to reverse this.
Answer : Continuous inbreeding among cattle causes inbreeding depression. It decreases the fertility and productivity of an animal. It can be overcome by applying outbreeding, in which mating is done between different breeds or individuals of the same breed but having no common ancestors. Outbreeding includes out-crossing, cross-breeding and interspecific hybridisation
Question. (i) Why is inbreeding necessary ? Give two reason.
(ii) What does continued inbreeding lead to ?
Answer : (i) Inbreeding is necessary if we want to evolve a pure line in any animal / plant.
(ii) Inbreeding exposes harmful recessive genes that are eliminated by selection leading to accumulation of superior genes. Continued inbreeding reduces fertility and productivity (Inbreeding depression).
Question. How is pure line in an animal raised ? Explain.
Answer : Pure line :
(i) A pure line animal is raised through inbreeding. It is a progeny of single, self-fertilized homozygous individuals.
(ii) A similar strategy is used for developing pure lines in cattle as was used in case of peas. Inbreeding increases homozygosity. Thus, inbreeding exposes harmful recessive genes that are eliminated by selection.
(iii) It also helps in accumulation of superior genes and elimination of less desirable genes. The selection increases the productivity of inbred population.
Question. Success rate of artificial insemination in cattle is fairly low. Identify any other technique to improve the successful production of hybrids. State two advantages of this technique.
Answer : Multiple Ovulation Embryo Transfer Technology increases herd size, in a short time.
Question. Differentiate between out-crossing and crossbreeding.
Answer :
Short Answer Type Question – l
Question. (i) Name any two fowls other than chicken reared in a poultry farm.
(ii) Enlist four important components of poultry farm management.
Answer : (i) Ducks, Geese and turkey.
(ii) Four important components of poultry farm management are :
(a) Selection of disease free and suitable breeds.
(b) Provision of proper and safe farm conditions.
(c) Provision of proper feed and water.
(d) Hygiene and health care.
Question. (i) State the objective of animal breeding.
(ii) List the importance and limitation of inbreeding.
How can the limitations be overcome ?
(iii) Give an example of new breed each of cattle and poultry.
Answer : (i) Increases the yield of animal and improves the desirable qualities of the produce. 1
(ii) Importance :
(a) Increases homozygosity which is necessary to evolve pure line in any organism.
(b) helps to expose harmful recessive genes.
(c) helps in accumulation of superior genes.
Limitation :
Continuous inbreeding among cattle causes inbreeding depression. It decreases the fertility and even productivity of an animal. It can be overcome by applying outbreeding, in which mating is done between different breeds or individuals of the same breed but having no common ancestors. Outbreeding includes out-crossing, cross-breeding and interspecific hybridisation.
(iii) Jersey / Hisardale – a new breed by crossing Bikaneri ewes and Miranio rams (cattle) and white Leghorn (poultry).
Question. Enlist the steps involved in inbreeding of cattle. Suggest two disadvantages of this practice.
Answer : Inbreeding involves mating of closely related individuals within the same breed for 4-6 generations.
Superior males and superior females of the same breed are identified and mated in pairs, the progeny are evaluated, superior males and females among them are selected for further mating.
Disadvantages : Continued inbreeding causes inbreeding depression, reduction in fertility, reduction in productivity.
Question. Explain how and why controlled breeding experiment is carried out in cattle.
Answer : Controlled breeding experiments are carried out using artificial insemination. Semen is collected from the male-chosen as parent, injected into the reproductive tract of the selected female
(cow), stored semen may be used later to conduct desirable matings.
Helps overcome several problems of normal mating, improve the quality and quantity of desired yield.
Question. Differentiate between inbreeding and outbreeding in cattle. State one advantage and one disadvantage for each one of them.
OR
Differentiate between inbreeding and outbreeding. Mention two advantages of inbreeding programme in cattle.
Answer : Inbreeding : Inbreeding refers to the mating between closely related individuals within the same breed for 4-6 generations.
Outbreeding : It refers to the breeding of unrelated animals either of the same breed but do not have common ancestor or of different breeds.
Advantage : Inbreeding brings the homozygosity in the population and helps in accumulation of superior genes and elimination of less desirable or harmful genes. Outbreeding is the best method of breeding for animals that have average productivity and growth.
Disadvantage : Continued inbreeding causes inbreeding depression i.e. reducing productivity and fertility. Outbreeding leads to loss of recessive characters.
Question. As a biologist explain the technique to a dairy farmer for increasing the yield of herd size of cattle in a short time.
OR
High yielding cattle is a good solution for food enhancement. How does the MOET technology help to increase the herd size ?
OR
MOET programme has helped in increasing the herd size of the desired variety of cattle. List the steps involved in conducting the programme.
Answer : Multiple Ovulation Embryo Transfer Technology (MOET) has helped the dairy farmer for increasing the yield of herd size of cattle in a short time. 1 In this method, a cow is administered hormones with FSH-like activity, to induce follicular maturation and super ovulation – instead of one egg, which they normally yield per cycle, they produce 6-8 eggs.
The animal is either mated with an elite bull or artificially inseminated.
The fertilized eggs at 8–32 cells stages are recovered non-surgically and transferred to surrogate mothers.
Question. (i) What is the programme called that is involved in improving success rate of production of desired hybrid and herd size of cattle ?
(ii) Explain the method used for carrying this programme for cows.
Answer : (i) Multiple ovulation embryo transfer method /
(MOET) is involved in improving success rate of production of desired hybrid and herd size of cattle.
(ii) High milk yielding cow administered hormone (with FSH like activity) → 6 to 8 eggs produced → inseminated artificially → fertilised eggs recovered non surgically at 32 cell stage → transferred to surrogate mother for further growth
Question. Enumerate any six essentials of good, effective dairy farm management practices.
Answer : Selection of high yielding and disease resistant breeds, well housed, adequate and clean water supply, maintain disease free feeding in a scientific manner with special emphasis on quality and quantity of fodder, regular visits by veterinary doctors, regular inspection and record keeping, cleanliness and hygiene of both the cattle and handlers while milking and transport.
Question. Explain out-breeding, out-crossing, and cross breeding practices in animal husbandry?
Answer : Out breeding : Breeding of unrelated animals (which may be between individual of same breed or between individuals of different species).
Out crossing : (a type of out breeding) mating of animals within the same breed but having no common ancestors on either side of their pedigree upto 4 – 6 generations.
Question. Mention and describe any three methods to overcome inbreeding depression in animal husbandry.
Answer : Three methods of overcoming inbreeding depression in animal husbandry are outcrossing, cross breeding and interspecific hybridization.
(i) Outcrossing is the mating between unrelated members of the different breed or same breed with common ancestors on either side of progeny upto
4-6 generations. (ii) In cross breeding the superior males and females of two different breeds are mated to obtain better progenies. (iii) The interspecific hybridization involves mating between members of two different species. This results in the formation of interspecific hybrids.
Question. (i) What is inbreeding depression ?
(ii) Explain the importance of ”selection” during inbreeding in cattle.
Answer : (i) Continuous inbreeding especially close inbreeding usually reduces fertility and even productivity / yield.
(ii) Helps in accumulation of superior genes / elimination of less desirable genes, increases homozygosity, pure lines, true breeding, helps to restore fertility, helps to increase yield / productivity, produces more milk per lactation, produces superior progeny, produces disease resistant breeds.
Question. (i) Write the scientific name of the most common species of honey bee reared.
(ii) Mention the kind of areas that are suitable for bee keeping practices.
(iii) Mention any two uses of bee wax.
Answer : (i) Apis indica is the most common species.
(ii) Bee keeping can be practiced in any area where there are sufficient bee pastures of some wild shrubs, fruit orchards and cultivated crops.
(iii) Bee wax is used in cosmetics and medicines.
Question. Write the aim with which animal breeding programmes are carried. Describe the essential steps be followed in poultry management.
Answer : Aims – increasing the yield of animals, improving the desirable qualities of the produce. Steps to be followed in Poultry Management :
(i) Selection of disease free and suitable breeds.
(ii) Proper and safe farm conditions.
(iii) Proper feed and water.
(iv) Proper hygiene and health care.
Question. What is ‘Blue Revolution’ ? Name two fresh water and two marine edible fish.
Answer : Rearing of aquatic animals (like fish and prawn), on large scale is called Blue Revolution. It has brought a lot of income to the farmers in particular and the country in general. Blue revolution is being implemented along the same lines as ‘Green Revolution’.
Fisheries have an important place in Indian economy. They provide income and employment to millions of fishermen and farmers. It is the only source of their livelihood.
Freshwater fish : Catla, Rohu and Common Carp.
Marine fish : Hilsa, Sardines, Mackerel and Pomphrets.
Question. State the objective with which a dairy farm is set up. Describe the essential steps to be followed for dairy farm management.
Answer : Processes and systems that increase yield and improve quality of milk
• Selection of good breeds having high yielding potential and resistance to diseases
• House to have adequate water and kept disease free
• Feeding in a scientific manner with quality fodder
• Storage and transport of milk and products
• Regular inspection with proper record keeping / Regular visits of veterinary doctor.
Long Answer Type Question
Question. Explain the efforts which must be put in to improve health, hygiene and milk yield of cattle in dairy farm.
Answer : Following efforts must be put in mainly to improve health, hygiene and milk yield of cattle in dairy farm:
(i) The cattle should be housed well in well ventilated sheds with adequate water supply.
(ii) There must be cleanliness and hygiene of both the cattle as well as the handlers while milking and transport.
(iii) Regular visit by veterinary doctors must be ascertained so as to keep the cattle healthy and disease free.
(iv) Feeding should be carried out in a most scientific manner with special emphasis on quality and quantity of fodder and the hygienic conditions.
(v) Breeding is necessary for improving the milk yield.
(vi) Selection of high yielding and disease resistant breed should be arranged.
(vii) Regular inspection and keeping updated record of all the activities of dairy is necessary.
TOPIC-2
Plant Breeding
Very Short Answer Type Question
Question. A certain tissue, of a plant, infected with TMV was used to obtain a new plant using tissue culture technique. Identify the technique used and reason out the possibility of obtaining a new healthy plant.
Answer : Tissue culture using meristematic tissue as it is virus free.
Question. State the economic value of Saccharum officinarum in comparison to S. barberi.
Answer : Saccharum officinarum has higher sugar content and thicker stem, whereas Saccharum barberi is inferior in sugar content and yield.
Question. Write an alternate source of protein for animal and human nutrition.
Answer : Single cell protein / Spirulina
Question. Why are living plant cell, said to be totipotent ?
Answer : The living plant cell are said to be totipotent because a whole plant can be generated from any living cell of the plant. They possess all the hereditary information and potentialities which enable them to differentiate into all type of cells which are present in the plant body.
Question. Name the following :
(i) The semi-dwarf variety of wheat which is highyieldingand disease-resistant.
(ii) Any one inter-specific hybrid mammal.
Answer : (i) Kalyan Sona / Sonalika
(ii) Mule / Hinny / Liger / Tigon.
Question. Name any two diseases the ‘Himgiri’ variety of wheat is resistant to.
Answer : (i) Leaf and stripe rust.
(ii) Hill bunt.
Question. How are the following two varieties of sugarcane different from each other ?
(i) Saccharum barberi
(ii) Saccharum officinarum.
Answer : Saccharum barberi has poor sugar content and yield, while Saccharum officinarum has higher sugar content and a thicker stem
Question. State the importance of biofortification.
Answer : Biofortification is the breeding of crops for improvement of nutritional quality. It is used to improve protein content and quality, to improve oil content and quality, to improve vitamins, etc.
Question. Name the semi-dwarf variety of wheat which is high yielding and disease resistant.
Answer : Sonalika and Kalyan-sona are the high yielding and disease resistant varieties of wheat.
Short Answer Type Question – l
Question. Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.
Answer : Steps for producing disease resistant plants are :
(i) Screening of germplasm (for resistance source).
(ii) Hybridization of selected parents.
(iii) Selection and evaluation of hybrids.
(iv) Testing and release of new varieties.
Question. How has mutation breeding helped in improving the production of mung bean crop ?
Answer : Mutation breeding has helped in improving the moong bean crop by producing its disease resistant varieties against yellow mosaic virus /powdery mildew. In mutation breeding, the mutations are induced artificially through the use of chemicals or radiations (like gamma rays) followed by selecting and using the plants that have desirable characters as a source in breeding.
Question. Identify ‘A’, ‘B’, ‘C’ and ‘D’ in the given table :
Answer : A → Wheat
B → Black rot and curl blight
C → White rust
D → Pusa Komal
Question. Enumerate four objectives for improving the nutritional quality of different crops for the health benefits of the human population by the process of
‘‘Biofortification’’.
Answer : Biofortification involves the breeding of crops to increase their nutritional value. The objective for biofortification are as follows :
(i) To improve protein content and quality.
(ii) To improve oil content and quality.
(iii) To improve vitamin content.
(iv) To improve micronutrients and mineral contents.
Question. By taking two examples, explain how has biofortification helped in improving food quality.
Answer : A maize hybrid was developed that had twice the amount of amino acid / lysine and tryptophan / Atlas 66 wheat variety having high protein content used as donor for improving cultivated wheat / Iron fortified rice / (IARI has released)
Vitamin A enriched carrots / spinach / pumpkin
Vitamin C enriched bitter gourd / bathua / mustard /tomato.
Iron & calcium enriched spinach / bathua
Protein enriched beans – broad / french peas / garden peas (Any two examples)
Question. In an agricultural field there is a prevalence of the following organisms and crop disease which are affecting the crop yield badly :
(i) White rust
(ii) Leaf and stripe rust
(iii) Black rot
(iv) Jassids
Recommend the varieties of crops the farmers should grow to get rid of the existing problem and thus improve the crop yield.
Answer : (i) Pusa Swarnim / Karan rai
(ii) Himgiri
(iii) Pusa Shubhra / Pusa Snowball K – 1
(iv) Pusa Sem 2 / Pusa Sem 3
Question. What is biofortification ? Mention the contribution of Indian Agricultural Research Institute towards it with the help of any two examples.
Answer : Breeding crops with higher level of vitamins and minerals or higher protein and healthier fats.
(i) Vitamin A enriched carrots / spinach / pumpkin.
(ii) Vitamins C enriched bitter gourd / bathua / mustard / tomato.
(iii) Iron and calcium enriched spinach / bathua.
(iv) Protein enriched broad lablab / french & garden peas.
Question. To reduce the percentage of population suffering
from hunger and malnutrition, microbes are grown on a large scale to act as food supplements. Mention any two microbes used as food supplement and suggest their role.
Answer : The two microbes used as food supplement are
Spirulina and Methylophilus.
Spirulina : Produces large quantities of food rich in protein, minerals, fats, carbohydrates and vitamins. Methylophilus methylotrophus— 250 gm of this microorganism produces 25 tonnes of protein per day.
Question. Name any two common Indian millet crops. State one characteristic of millets that has been improved as a result of hybrid breeding so as to produce high yielding millet crops.
Answer : Two common Indian millet crops are Maize and Jowar. Hybrid breeding has resulted in the production of high yielding millet varieties that are resistant to pest attack and water stress.
Question. List the two steps that are essential for carrying out artificial hybridization in crop plants and why ?
Answer : Step 1 : Hybridization of pure lines
Step 2 : Artificial selection These steps help to produce plants with desirable traits such as high yield, nutrition and resistance to diseases.
Question. Life style diseases are increasing alarmingly in India. We are also dealing with large scale malnutrition in the population. Suggest a process by which we can address both these problems. Give any three examples to support your answer.
Answer : Biofortification
a) Enhancing food quality with respect to protein- Maize hybrids that had twice the amount of the amino acids, lysine and tryptophan, compared to existing maize hybrids were developed. Or Wheat variety, Atlas 66, having a high protein content has been used as a donor for improving cultivated wheat.
Or Protein enriched beans- broad, lablab, French and garden peas.
b) Vitamin enriched- Vitamin A enriched Carrots, Spinach, Pumpkin Or Vitamin C enriched bitter gourd, bathua, mustard, tomato.
c) Enrichment of Micro Nutrient and Mineral content- Iron and calcium enriched spinach and bathua.
Question. How can healthy potato plants be obtained from a desired potato variety which is viral infected ? Explain. A [Delhi Set-II, 2014]
Answer : Healthy potato plants can be obtained from a desired potato variety which is viral infected by the method of tissue culture. The apical and axillary meristems of the infected plant is virus free. Hence, they can be removed and grown in vitro to obtain healthy potato plants. This is one of the applications of tissue culture.
Question. How are biofortified maize and wheat considered nutritionally improved ?
Answer : Biofortified maize and rice are quite rich in amino acids and proteins. Biofortified maize contains twice the amount of amino acids like lysine and tryptophan as compared to existing varieties and biofortified wheat, which has increased amount of protein.
Question. (i) Why are the plants raised through micropropagation termed as somaclones ?
(ii) Mention two advantages of this technique.
Answer : (i) Genetically identical.
(ii) Large number of plants in short duration, virus free plants.
Question. (i) ‘‘Fortification of crops is the need of the hour.’’
Give two reasons.
(ii) Select one fresh-water and one marine fish from the following : Prawn; Catla; Mackerel; Lobster.
Answer : (i) To improve the nutritional quality in order to improve public health / to prevent malnutrition.
(ii) Fresh water : Catla, Marine Fish : Mackerel.
Question. You have obtained a high yielding variety of tomato. Name and explain the procedure that ensures retention of the desired characteristics repeatedly in large populations of future generations of the tomato crop.
Answer : Tissue culture / micropropagation / somaclonal propagation / apomixis.
(a) Explant / any part of plant taken out and grown (in a test tube / vessel).
(b) under sterile condition.
(c) in special nutrient medium (containing carbon source / sucrose, inorganic salt / vitamins / amino acids and growth regulator)
Short Answer Type Question – ll
Question. A sugarcane has been affected by virus. How can a virus free cane developed from it ?
Answer : Virus free sugarcane can be developed by tissue culture technique. The meristematic regions of a plant are generally free from virus. Healthy and
virus free sugarcane plants can by developed by this technique using meristems as explants. Procedure : Explants obtained from the meristem apical or young axillary buds or from nodes near the stem apex are taken and surface sterilized by 0.5% sodium hypochlorite and then seeded over the nutrient agar medium enriched with cytokinin under aseptic conditions. After incubation for a few days under optimal conditions the explants give rise to shoots. These shoots are cut into nodal segments of 2-3 cm which are then transferred into a medium containing extra auxin for promoting root formation. This results in the development of a number of plantlets, which are then transferred to fields.
Question. (i) Write two limitations of traditional breeding technique that led to promotion of micropropagation.
(ii) Mention two advantages of micro-propagation.
(iii) Give two examples where it is commercially adopted.
Answer : (i) Failed to keep pace with demand, failed to provide fast and efficient system of crop improvement.
(ii) Large number of plants can be developed in a short duration / production of genetically identical plants / somaclones / healthy plants can be recovered from diseased plants.
(iii) Tomato / banana / apple.
Question. The Indian Agricultural Research Institute has introduced several cereal and vegetable crops that are nutritionally rich in vitamins and minerals. What is this kind of breeding called? Write the main objectives with which such breeding programme is carried.
Answer : Biofortification
Objectives : Improving –
(i) Protein content and quality.
(ii) Oil content and quality.
(iii) Micronutrient and mineral content.
(iv) Vitamin content.
Question. IARI has released several varieties of crop plants that are biofortified. Give three examples of such crops and their biofortifications.
Answer : The biofortified crops released by IARI are :
(i) Carrots enriched with Vitamin A.
(ii) Bittergourd-rich with Vitamin C.
(iii) Spinach enriched with calcium and iron.
Question. Plant breeding technique has helped sugar industry in North India. Explain how.
Answer : Two species (Saccharum barberi and Saccharum officinarum) were crossed to get sugarcane varieties with high yield / thick stem / high sugar content / ability to grow in North India.
Question. Scientists have succeeded in recovering healthy sugarcane plants from a diseased one.
(i) Name the part of the plant used as explant by the scientists.
(ii) Describe the procedure the scientists followed to recover the healthy plants.
(iii) Name this technology used for crop improvement.
Answer : (i) Meristem (apical, axillary) or shoot tip or nodal segment.
(ii) Procedure, the scientists followed to recover healthy plants is :
Explant / Virus free meristem is grown in nutrient medium, under aseptic conditions, tissue proliferates to form undifferentiated mass called callus, transferred to a medium containing auxins and cytokinins, regeneration of plants from callus, Hardening of plantlets, transfer of regenerated plantlets to field
conditions.
(iii) Tissue culture / micropropagation.
Question. (i) Mention two advantages of micropropagation.
(ii) Give two examples where it is commercially adopted.
Answer : (i) Advantages of micropropagation are :
(a) A large number of plant can be produced in a short duration.
(b) The plants produced are genetically identical.
(c) Healthy plants can be obtained from the diseased plants.
(ii) Micropropagation is commercially adopted in case of :
(a) Tomato (b) Banana (c) Apple.
Question. What is single cell protein ? Give its importance and two examples of SCP.
Answer : Single cell protein is the large quantities of biomass produced by culturing single type of cells or microorganisms, which serve as food specially rich in protein, fats, carbohydrates, minerals and vitamins.
Importance :
(i) It serves as rich source of protein in human diet.
(ii) It reduces pressure on agricultural production system for the supply of protein requirement.
(iii) It helps in reducing environmental pollution.
Examples :
(a) Spirulina–a cyanobacterium or blue green algae.
(b) Methylophilus methylotrophus–a bacterium
Question. How can pollen grains of wheat and rice which tend to lose viability within 30 minutes of their release be made available months later for breeding programmes ?
Answer : The pollen grains can be preserved at low temperature preferably in liquid nitrogen
(temperature-196°C). Such stored pollen remain viable for years together and therefore can be used in breeding programmes
Question. How can crop varieties be made disease resistant to overcome food crisis in India ? Explain. Name one disease resistant variety in India of :
(i) Wheat to leaf and stripe rust.
(ii) Brassica to white rust.
Answer : The crop varieties can be made disease resistant so as to overcome food crisis in India by usual and conventional methods of breeding or mutation
breeding for disease resistance by hybridization and selection. The various sequential steps of this programme are screening germplasm for resistance sources, hybridization of selected parents, selection and evaluation of the hybrids and testing and release of new varieties // mutation breeding. It is possible to induce mutations artificially through use of chemicals or radiations (like gamma radiations) and selecting and using the plants of desirable character as a source in breeding. Selection amongst somaclonal variants / Genetic engineering.
(Any one explanation)
(i) Variety of wheat resistant to leaf and stripe rust is Himgiri.
(ii) Variety of Brassica resistant to white rust disease is Pusa swarnim / Karan rai.
Question. GM plants are useful in many ways. How would you convince farmers to grow GM plants on their field ? Explain giving three reasons.
Answer : Make crop more tolerant to abiotic stresses / Reduce reliance on chemical pesticides / Help to reduce post harvest loses / Increase efficiency of mineral usage / Enhance nutritional value of food.
Question. How are somaclones cultured from explants in vitro conditions? Why are somaclones so called ?
Answer : Explant is a part of a plant used in tissue culture. For developing the somaclones, the explants is grown in nutrient medium under aseptic conditions. This results in the formation of an undifferentiated mass of tissue called callus from which a large number of plantlets are produced by micropropagation.
These plants so produced by tissue culture are called somaclones because they are genetically identical to the original plant from which the explant is taken.
Question. What is “biofortification” ? Write its importance. Mention the contribution of Indian Agricultural Research Institute towards it with the help of two examples.
Answer : The process of breeding crops for higher level of vitamins and minerals, higher proteins, healthier fats, to improve public health is known as biofortification.
It helps to improve :
(i) Protein content and quality.
(ii) Oil content and quality.
(iii) Vitamin content and
(iv) Micronutrient and mineral content.
IARI has released several vegetable crops that are rich in vitamins and minerals e.g. Vitamin A enriched carrots, spinach, pumpkin, vitamin C enriched bitter gourd, bathua, mustard, tomato, iron and calcium enriched spinach and bathua, protein enriched beans–lablab, broad, French and garden pea.
Question. (i) What is green revolution ? Mention the steps that led to it.
(ii) Name the scientist whose contribution led to development of semi-dwarf wheat varieties in India.
Answer : (i) Dramatic increase in food production (wheat and rice) during the mid 1960’s is termed as Green Revolution by various plant breeding techniques / better management practices / use of agrochemicals (fertilizers and pesticides).
(ii) Norman E. Borlaug
Question. (i) Name the tropical sugar cane variety grown in South India. How has it helped in improving the sugar cane quality grown in North India ?
(ii) Identify ‘a’, ‘b’ and ‘c’ in the following table :
Answer : (i) Saccharum officinarum, crossed with, North Indian variety (Saccharum barberi) to increase quality.
(ii) (a) Aphids
(b) Jassids / aphids / fruit borer
(c) Okra (Bhindi)
Long Answer Type Question
Question. With advancement in genetics, molecular biology and tissue culture, new traits have been incorporated into crop plants.
Explain the main steps in breeding a new genetic variety of crop.
Answer : Main steps involved in breeding a new genetic variety of a crop are :
(i) Collection of variability / germplasm collection and preservation of all different wild varieties, species and relatives of cultivated species / entire collection of plants.
(ii) Evaluation and selection of parents to identify plant with desirable combination of character / purelines are created.
(iii) Cross hybridization among selected parents: cross hybridizing the two parents to produce hybrids with genetically combine desired characters in one plant.
(iv) Selection and testing of superior recombinants: selection among the progeny of the hybrids that have desired character combinations, superior to both the parents / self pollinated for several generations till they reach the state of uniformity and they do not segregate in the progenies.
(v) Testing, release and commercialisation of new cultivars, newly selected lines are evaluated for yield / other agronomic traits of quality / disease resistance by growing them in research fields followed by testing the material in farmers fields for atleast three growing seasons at different agroclimatic zones.
(vi) Release of new variety : The variety evaluated is selected, certified and released as new variety.
Question. (i) What is plant breeding ? List the two steps the classical plant breeding involves.
(ii) How has the mutation breeding helped in improving crop varieties ? Give one example where this technique has helped.
(iii) How has the breeding programme helped in improving the public nutritional health ? State two examples in support of your answer.
Answer : (i) Plant breeding is the science of changing the genetics of plants in order to produce desired characteristics. Plant breeding can be done through many different techniques ranging from simply selecting plants with desirable characteristics for propagation.
Classical plant breeding uses : (a) Deliberate interbreeding (crossing) of closely or distantly related individuals to produce new crop varieties with desirable properties.
(b) In-vitro techniques such as protoplast fusion, mutagenic agents.
(ii) Mutagenic agents such as radiation and certain chemicals are used to induce mutations and generate genetic variations from which desired mutants may be selected.
Treatment with mutagens alters genes or breaks chromosomes. Gene mutation occurs naturally as errors in DNA replication e.g. a mutant of paddy rice.
(iii) Plant breeding helps in increased food production by :
(a) Development of high-yielding crops.
(b) Improved management practices.
(c) Provisions of genetically derived better seed germplasm. Breeding crops with higher levels of vitamins and minerals or higher protein and
healthier fats is the most practical means to improve public health.
Examples of crop plants with enhanced nutritional qualities and which have been developed by IARI New Delhi are :
(i) Golden maize : This is a hybrid variety which is rich in amino acids lysine and tryptophan.
(ii) Wheat variety Atlas-60 : It is protein rich variety.
(iii) Golden rice : It is iron rich fortified variety of rice.
Question. (i) Name the technology that has helped the scientists to propagate on large scale the desired crops in short duration. List the steps carried out to propagate the crops by the said technique.
(ii) How are somatic hybrids obtained ?
Answer : (i) Tissue culture / micro propagation.
Explants are grown in a test-tube, under sterile condition, in special nutrient medium / culture medium.
(ii) Isolated single cells, digests cell walls, to obtain naked protoplast from two different varieties, fusion of protoplast.
Hybrid protoplasts thus, obtained are cultured in a suitable medium to form new plants.
Somatic hybridisation : (i) Isolation of protoplasts using enzymes pectinase and cellulase
(ii) Protoplasts fusion induced by PEG
Question. What is somatic hybridization? Explain the various steps involved in the process. Mention any two uses of somatic hybridization.
Answer : The process of fusion of protoplast of somatic cells derived from different varieties or species of plants on a suitable nutrient medium to produce the somatic hybrids is called somatic hybridization. For example pomato is the somatic hybrid obtained by the protoplast fusion of tomato and potato.
The steps involved in somatic hybridization are :
(i) Single cells isolated from the selected plants.
(ii) Removal of cell wall of the fusing cell with the help of the enzymes like pectinase and cellulase. These enzymes digest the cell wall to expose the naked protoplast.
(iii) The isolated protoplasts of selected parents are fused to obtain hybrid protoplast on special nutrient medium under aseptic conditions. This fusion is induced in the presence of polyethylene glycol (PEG) or by a brief high voltage electric current.
(iv) The hybrid protoplast are cultured on suitable nutrient medium, where they regenerate cell wall and begin to undergo division to form new plantlets. These plantlets are the somatic hybrids.
Use of somatic hybridization :
(a) Species of plants in which sexual hybridization or breeding is not possible can be hybridized by somatic hybridization.
(b) Somatic hybridization produces hybrids between those lines or species where it is not possible through sexual hybridization.
(c) This technique is useful in raising allopolyploids.
