VBQs Class 12 Biology Strategies for Enhancement in Food Production
Very Short Answer Type Questions
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. 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 highyielding and disease-resistant.
(ii) Any one inter-specific hybrid mammal.
Answer : (i) Kalyan Sona / Sonalika
(ii) Mule / Hinny / Liger / Tigon.
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.
Short Answer Type Questions
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. Why are microbes like Spirulina being produced on a commercial scale ? Mention its two advantages.
‘‘Large scale cultivation of Spirulina is highly advantageous for human population.’’ Explain giving two reasons.
“Growing Spirulina on a large scale is beneficial both environmentally and nutritionally for humans.“ Justify.
Answer : As source of food protein.
Reduces environmental pollution / solves problem of hunger and malnutrition / rich source of protein / low cost production.
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
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
(iii) Pusa Shubhra / Pusa Snowball K –
(iv) Pusa Sem 2 / Pusa Sem
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 Detailed Answer :
(i) Maize hybrids having twice the amount of amino acids, lysine and tryptophan.
(ii) Wheat variety, Atlas 66, having high protein content.
(iii) Iron fortified rice variety containing over five times as much as iron as in common varieties.
(iv) Indian agricultural Research institute, New Delhi has produced variety of vegetable crops
rich in vitamins and minerals such as vitamin A enriched carrots, spinach, pumpkin, vitamin C enriched bitter gourd, bathua, mustard, tomato, iron and calcium enriched spinach and bathua, protein enriched beans.
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. 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. How can healthy potato plants be obtained from a desired potato variety which is viral infected ?
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. 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. (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. 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. 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.
Detailed Answer :
(i) Saccharum barberi was originally grown in north India, but had poor sugar content and yield.
(ii) Saccharum officinarum, which was used to be grown in South India, had thicker stems and higher sugar contents. However, it did not grow well in North India.
(iii) These two species were crossed to get sugar cane varieties with the desirable qualities of high yield, thick stems, high sugar and ability to grow in the sugar cane areas of north India.
(iv) This breeding experiment helped in the growth of the sugar industry in north India.
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. 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. 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. (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. 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.
Detailed Answer :
(i) Biofortification is the method of breeding crops with higher levels of nutrients which help to improve public health.
Objectives of Biofortification or Breeding for Improved Nutritional Quality :
(ii) To improve protein content and quality.
(iii) To improve oil content and quality.
(iv) To improve vitamin content.
(v) To improve micronutrient and mineral content.