Page 35 - Introduction to Agriculture by: Aqleem Abbas

Introduction to Agriculture Notes prepared by: Aqleem Abbas

temperature e.g. sugar cane, mango, banana, papaya, pineapple, cotton, mango, maize, rice, millet,
sorghum, sugar can

Subtropical crops

These crops tolerate some sub freezing temperatures but cannot grow well in temperate or tropical zones.
Subtropical belt includes both humid and semi arid zones. Subtropical fruit plants are killed by temp
below -7 degree centigrade e.g. citrus, date, fig, and pomegranate.

Photoperiod

Plants grown vegetatively produce leaves and branches, then change from vegetative to reproductive
stage by producing flowers and fruits. This change is brought about by changes in day length i.e. number
of hours of light. Crops are classified according to their responsive to day length which is known as
photoperiodism.

Short day plants

Short day plants are those plants which change from vegetative to reproductive stage when day become
short for example rice require less than fourteen hours.

Long day plants

They change from vegetative to reproductive stage when the days become longer e.g. wheat, barley,
greater than fourteen hours.

Day neutral plants

Plant whose initiation of flowering is not affected by the length of days e.g. tomato, cucumber and okra.

Classification of crops on basis of growth habit

Based on vegetative and reproductive mode plants are classified into

Determinate plants

Those who initiate their reproductive stage after completion of vegetative stage . They can be harvested
only once. E.g. wheat, rice and maize.

Indeterminate plants

These are those crops which continue simultaneously both vegetative and reproductive stage at the same
time on the same plants. These plants have both mature and immature fruits, flowers and buds on the
same plant at a time.

For example

Soybean, mung bean, pea, tomato, cucurbits