Potatoes

Potatoes: an overview
The potato (Solanum tuberosum) originates from South America, most likely from the
central Andes in Peru. The potato was domesticated and has been grown by
indigenous farming communities for over 4,000 years. Introduced into Europe in the
sixteenth century, the crop subsequently was distributed throughout the world,
including Asia (Smith, 1995).
The potato is a major staple fulfilling human nutritional requirements. Worldwide, the
potato comes forth in terms of production after wheat, maize, and rice. In many
countries potato serves as their staple food because of its excellent nutritional
content.
According to Indonesian farmers, the advantages of the potato over other crops are:
• Its potential for high productivity.
• Its potential for being extremely profitable and easily marketed.
• Its price is relatively stable.
Its production challenges include:
• It is vulnerable to pests and diseases hence implying a high risk of failure.
• Growing potatoes requires substantial capital.
• It needs intensive care and attention.
The main constraints to potato farming in Indonesia are farmers’ lack of healthy seed,
and attack by late blight, bacterial wilt, viruses, and leafminer fly. Other important
constraints for farmers include potato tuber moth, weeds, unfavorable weather, low
soil fertility, inadequate post harvest management, and marketing.

The potato plant
The potato plant consists of the following parts: leaves, stems, roots and tubers.
Some potato varieties planted in particular environments can produce flowers and
berries. The function of each of these plant parts are as follows:
• Leaves are the part of the plant used for supplying nutrients.
• Stems are for supporting plants, and have vessels and growth cells inside.
• Roots absorb nutrients from within the soil.
• Tubers are receptacles for storing nutrients.
2.2 Potato plant growth
There are no fixed development stages in potatoes as these are influenced by
varieties, shoot size, soil fertility, weather etc. Unlike rice, potato development
stages overlap with each other making it difficult to distinguish between stages. For
example, sometimes during the early growth stage, developing tubers have already
begun to grow from the roots. Nevertheless, a division of potato growth stages can
provide a picture of crop’s critical development periods. This knowledge is
extremely important for developing management strategies.
Potatoes planted from seed have the following growth stages:
Sprout development stage
This stage begins with several eyes sprouting when the tuber is in storage,
continues through planting and up until shoots emerge from the surface of the
soil. The time involved for the shoots to emerge from the ground varies
greatly depending on the length of the shoot, moisture in the soil and
other environmental conditions. With a sprout at the ideal length of 1-2
cm, shoots should begin emerging from the ground at around 21-30
days after planting (DAP). During this stage the plant still uses nutrient
reserves stored in the tuber.
Vegetative growth stage
This stage shows rapid growth of leaves, stems, new shoots and
roots. The plant still relies on food reserves stored in the seed tuber,
but has already begun to take small quantities of nutrients from the
soil. With the Granola variety this stage generally occurs between 30-
50 DAP.
Tuber initiation stage
In the Granola variety, although tuber-forming roots begin to form
during the vegetative stage, formation of actual tubers only occurs at
40-55 DAP. This stage takes place over a relatively short period of
about 10-15 days. Tubers formed after 65 DAP will not reach
optimum size when harvested. Plants require nutrients in large
quantities during this stage.