Page 153 - Understanding NCERT Science 09

the kharif season from the month of June to
Fig. 12.1: Different types of crops
Q 1. What do we get from cereals,
uestion
pulses, fruits and vegetables?
Different crops require different climatic
conditions, temperature and photoperiods for
their growth and completion of their life cycle. results in genetically modified crops.
Photoperiods are related to the duration of
sunlight. Growth of plants and flowering are
dependent on sunlight. As we all know, plants
manufacture their food in sunlight by the
process of photosynthesis. There are some
crops, which are grown in rainy season, called particular variety, that is, the seeds should all
IMPROVEMENT IN FOOD RESOURCES
Rationalised 2023-24
October, and some of the crops are grown in
the winter season, called the rabi season from
November to April. Paddy, soyabean, pigeon
pea, maize, cotton, green gram and black
gram are kharif crops, whereas wheat, gram,
peas, mustard, linseed are rabi crops.
In India there has been a four times
increase in the production of food grains from
1952 to 2010 with only 25% increase in the
cultivable land area. How has this increase
in production been achieved? If we think of
the practices involved in farming, we can see
that we can divide it into three stages. The
first is the choice of seeds for planting. The
second is the nurturing of the crop plants.
The third is the protection of the growing and
harvested crops from loss. Thus, the major
groups of activities for improving crop yields
can be classified as:
• Crop variety improvement
• Crop production improvement
• Crop protection management.
12.1.1 CROP VARIETY IMPROVEMENT
This approach depends on finding a crop
variety that can give a good yield. Varieties or
strains of crops can be selected by breeding
for various useful characteristics such as
disease resistance, response to fertilisers,
product quality and high yields. One way of
incorporating desirable characters into crop
varieties is by hybridisation. Hybridisation
refers to crossing between genetically
dissimilar plants. This crossing may be
intervarietal (between different varieties),
interspecific (between two different species of
the same genus) or intergeneric (between
different genera). Another way of improving
the crop is by introducing a gene that would
provide the desired characteristic. This
For new varieties of crops to be accepted,
it is necessary that the variety produces high
yields under different conditions that are
found in different areas. Farmers would need
to be provided with good quality seeds of a
141