Production regions: Sri Lanka
The 3 main production areas are: Nuwara Eliya, Badulla and Jaffna/Badulla.
Nuwara Eliya is a Highlands area, favourable for potato production. Late blight is a serious problem and an intensive spraying programme is needed. Virus degeneration is relative low. The farm sizes are relatively small, but there are a limited number of larger State Farms (Potato farms and Dairy farms). Many of the small farms are infested with brown rot. Because of a reasonable wide rotation State farms are relatively clean from brown rot.
Temperatures are such that in naturally ventilated stores potato seed can be stored for up to 6 months. In diffuse light stores 8-9 months may be possible with some varieties.
Badulla is at Mid-elevation. There are two production periods. In the second season potatoes are planted in flood irrigated rice fields. In these paddy fields most of the brown rot in the soils is killed and most potato crops are free from this disease if clean seed is used. Since temperatures are relatively high, late blight is less of a problem (especially in the P4- H4 season when there is less rain).
Jaffna is situated in the Low-land where potatoes can only be grown during the coolest season. In the storage season temperatures are high and storage of potatoes is difficult.
Seed production areas and seed-flows are given in a diagram.
Potatoes harvested at H1 (Nuwara Eliya) are still physiologically rather young when planted in the P2 (Nuwara Eliya) planting season, but are at a good physiological stage when planted in
P3 (Badulla) and P5 (Jaffna). For the second planting season in Badulla - P4, the seed is either coming from H2 (Nuwara Eliya) or from H3 (Badulla).
Nuwara Eliya key role
In fact Nuwara Eliya plays a key role in the seed supply of the country.
The possible seed sources for P1 in this area are:
- from H1 (Nuwara Eliya) cold stored or diffuse light stored seed,
- from early H2 (Nuwara Eliya) seed or
- H4 (Badulla) seed.
Recycling the seed in Nuwara Eliya may give physiological problems as well as problems with brown rot.
In the P4-H4 (Badulla) season infection by virus is rather high and seed may degenerate fast.
Many fields in Nuwara Eliya are infected by brown rot. To reduce this problem and to avoid further spreading of it, crop rotation and seed flushing are necessary.
For seed flushing relatively large quantities of clean basic seed are required. There are doubts whether a pre-basic seed programme, which can produce a sufficient quantity of clean seed is feasible. When multiplied for a number of generations it is difficult to keep basic seed stocks free from brown rot. Additional seed imports will be needed.