Potato and Tuber Crops

Botany

• Cassava belongs to family Euphorbiaceae and is diploid (2n=36).
• Polyploids with 2n=54 and 72 are also available.
• It is a perennial shrub producing 5-10 cylindrical tubers per plant.
• Being a member of family Euphorbiaceae, it produces latex.
• The stem is woody and variously branched.

Two distinct types of stems are present

1. Without branching at the top
2. With spreading nature.

• Leaves are palmately lobed with 5-9 lobes.
• Cassava is monoecious in nature and cross-pollinated. Female flowers are a few in numbers and are borne in the base of inflorescence and male flowers are borne above. Female flowers open about 10 days before male flower anthesis.
• Stigma is receptive from 6.30 a.m. and continues up to 2.30 p.m. Plants when raised from seeds produce typical tap root system.
• Since crop is mainly propagated by vegetative means by stem cuttings, numerous adventitious roots develop, of which a few develop into tubers.
• Tubers are composed of a thin periderm, white or purple cortex known as rind and central massive flesh rich in starch (25-40%). Bitterness often encountered in a few varieties and at certain stage is due to a bitter principle cyanogenic glucoside (HCN).