In-vitro multiplication
Test Tube
With this method sterilized buds from selected healthy plants are put into test tubes on a solid growth medium of Murashinge and Skoog and placed at 20 oC in light. After one month, the plantlets (4-9 buds) are cut into separate pieces each with a single bud; each bud is transplanted into a test tube with fresh medium. This procedure is repeated successively. The multiplication rate is high using this method. One bud can, in theory, produce 4 000) to 500 000) plantlets within 6 months.
In - vitro multiplication.... Example in vitro multiplication based system
Screen house
The rooted plantlets are planted in soil (mixture: clay, sand an peat or compost) in pots (for transport) or directly in beds in a screen house. A commonly used planting distance is 12x12 cm (70 plants/m2). Each plantlet may produce 2-5 mini-tubers.This is 138- 347 tubers/m2 of screen-house bed . Adding 5 cm of soil to the beds when plants are 12-15 cm high has a positive effect, it increases the number of tubers per plantlet. It is essential that screen houses are kept aphid free, that the soil used is sterilized and that the water for irrigation is free from bacteria.
EXAMPLE BOLIVIA
Field
The most delicate phase in pre-basic and basic seed production from rapid multiplication is the first field multiplication of mini tubers.
FIRST FIELD MULTIPLICATION
When to use?
The advantage of this method is that in a short time relatively large stocks of pre-basic seed can be produced. The method is expensive and only justified when the degeneration can be kept low so as to ensure that the seed stock still has the quality required for basic seed after 3-4 field multiplications