Seed rate and crop density

Crop density:
The crop density is expressed as: For table potatoes the density is 40 000 plants/HA or 15-20 stems per m2.
For seed the density may be as high as 60 000 plants/HA or 30 stems per m2.
Seed vs. Table/Ware Potato production

Seed rate:
A stem density of 15 stems/m2 or 30 stems/m2 can be reached by planting different sizes of seed.

Seed size / Seedweight
The seed sizes:(< 35 mm , 35-45 mm, 45-55 mm) are commonly used.
Relation seed size and seed weight-----Seed size

Stem density:
The number of stems per m2 is a more accurate manner to express crop density than number of plants per hectare.
Total yield increases until a density is reached of approximately 15-20 stems per m2. With a further increase of stem density the yield remains more or less the same, but the average tuber size decreases (relatively more small tubers).
Graph: density-yield-tuber size

Seed sizes:
The seed sizes are expressed in diameter: < 35 mm , 35-45 mm, 45-55 mm and > 55 mm.
The same density can be reached with large sized seed and with small sized seed. The price of the different seed sizes determines the preference of the user:
Producers of table potatoes have a certain preference for smaller sized seed, while seed growers often use their bigger sized tubers for re-multiplication as seed.
Mini-tubers from rapid multiplication programs are often very small (e.g. 10-30 mm) and require special care in the first field multiplication (eg shallow planting, cover with perforated plastic).
SEED CUTTING

Size and vigour:
The seed size not only has an effect on stem number, but also on the early development of the crop.
Seed size-vigour, number of stems
Larger sized seed gives an early and vigorous crop.
Mini-tubers(10-30 mm) from rapid multiplication programs, are slow in their early development and crops grown from these tubers require a relatively long growing period.
Development mini tubers