Improvement in Food Resources - Class 9 - Part 2

1. Chapter 15
Improvement in Food Resources
Part 2
Class 9
SA1

2. What are we going to Learn?
• How crop varieties can be improved?
• What are the factors against which variety
needs to be improved?
• What are the techniques to improve crop
variety? – Hybridization and Gene
Manipulation
• How the crops are provided with Nutrition to
give a better yield? Manure and Fertilizers.

3. Crop Variety Improvement
Q: What is Crop Variety Improvement? Why is it important to improve our crop
yield and quality?
• Crop Variety Improvement depends on finding a crop that can give a good yield.
Such varieties are specifically chosen to give better yield even in many adverse
environmental conditions.
• Some of the factors for which variety improvement is done are:
a) Higher yield: for increasing the productivity per acre of land.
b) Improved quality: quality considerations vary from crop to crop as per the
requirements.
c) Biotic and abiotic resistance: crops should have sufficient resistance to biotic
factors (living -diseases, insects and nematodes) and abiotic stresses (non-living -
heat, cold, frost etc.)
d) Change in maturity duration: the shorter the duration, the more economical is the
variety.
e) Wider adaptability: it can be grown in different climatic conditions.
f) Desirable agronomic characteristics: Special Traits that are desired . Tallness and
profuse branching for fodder crops. Dwarfness is desired for cereals.

4. Techniques of Crop Variety
Improvement
• Crop variety improvement can be achieved by two methods;
Hybridisation and Genetically modified crops.
• Hybridisation: In genetics, hybridisation is the process of combining
different varieties or species of organisms which are genetically
dissimilar to create a hybrid. The hybrid so obtained, will have
desired qualities of both the Parent varieties.
• It can be inter varietal(between different varieties), inter specific,
(between different species) , intergeneric (between different
genus)
• Genetically modified crops: The crop is improved by introducing a
gene that would provide desired characteristics.
• BT Gene obtained from bacteria, introduced into Cotton plant,
provides pest resistance against Ball Worm. This saves the cotton
crop from damage. The Cotton so obtained is called “BT Cotton”

5. CROP PRODUCTION
(Providing Nutrition to the improved variety)
• It involves different practices carried out by
farmer to achieve higher standards of crop
production. Also to obtain higher yield and
quality, Appropriate nutrition must be provided.
It includes the following:
a)NUTRIENT MANAGEMENT (MANURE,
FERTILIZERS AND ORGANIC FARMING)
b)IRRIGATION
c) CROPPING PATTERN

6. NUTRIENT MANAGEMENT
• There are 16 nutrients which are essential for plants as deficiency
of these nutrients will affect the physiological processes of plants
such as growth, reproduction etc.
• Out of these nutrients 13 nutrients are supplied by soil; oxygen and
carbon by air; hydrogen by water.
• Out of 13 nutrients 6 are classified as Macronutrients and rest as
Micronutrients.
• MICRONUTRIENTS- they are needed in only very small (micro)
quantities. They are also called as minor elements or trace
elements. These include elements like boron, zinc etc.
• MACRONUTRIENTS: they are required by plants in relatively large
amounts. The major macronutrients are nitrogen (N), phosphorous
(P), potassium (K),Calcium (Ca), magnesium
• (Mg), and sulfur (S).

7. METHODS INVOLVED IN ENRICHING
THE SOIL TO INCREASE THE YIELD
• MANURE: it is defined as the decomposition of animal excreta and plant waste.
• Advantages of Manure
1. Manures helps in enriching the soil with organic matter and nutrients.
2. It helps in increasing the soil fertility.
3. Water holding capacity of soil is increased.
4. Helps in improving soil texture.
5. Save our environment from excessive use of fertilizers.
Manure is classified into two types according to the biological material used:
A) Compost and Vermi-compost:
• Composting is the process in which farm waste material (cow dung, domestic waste, sewage waste
etc) is decomposed in pits. Compost is the aerobically decomposed remains of organic matter
which is rich in nutrients.
• Vermicomposting: it is the process which involve use of earthworms to hasten the process of
decomposition of plant and animal refuse.
B) Green Manure:
• Plants like sun hemp or guar are grown and mulched by ploughing them into soil which is turned
into green manure. It helps in enriching the soil in nitrogen and phosphorus.

8. • FERTILIZERS:
• These are produced commercially from chemicals rich in nitrogen, phosphorus and
potassium.
• Advantage: they help in good vegetative growth and produce healthy and
commercially viable plants.
• Disadvantages of fertilizers:
a) Excessive use of fertilizer leads to pollution of water.
b) Continuous use of fertilizer lead to decrease in soil fertility because organic matter
of the soil cannot be replenished as microorganisms present in soil get harmed
due to fertilizers.
• ORGANIC FARMING:
• It’s a farming system in which use of chemicals such as fertilizers, herbicides,
pesticides etc are reduced
• It involves the use of following components:
a) Organic manure
b) Recycled farm waste
c) Bio-agents such as culture of blue green algae in preparation of bio fertilizers
d) Bio pesticides such as leaves of neem or turmeric for grain storage
e) Healthy cropping patterns such as mixed cropping, intercropping and crop rotation
which will also help in controlling growth of weed, pest and insects.

9. Review Questions
What are the factors against which Crop
Varieties need to be improved?
What is hybridisation? What are its
advantages?
How is gene manipulation beneficial to the
crop? Suggest suitable example.
Why is the use of Fertilizers discouraged?
What are the practices utilized by a farmer
that are collectively called “Organic Farming”?

10. The BT Brinjal Controvery in India