Potato (Solarium tuberosum L.) is a major food crop for farmers of higher elevations (> 2000 m) in Nepal. Farmers plant potatoes in early spring after snow melt, utilizing residual winter moisture and occasional pre-monsoon rains for crop growth. The growing season is usually ended by late blight (LB, Phytophthorainfestans) after the onset of the monsoon. However, drier areas of the interior of W. Nepal regularly experience drought and impaired plant growth before the monsoon, and the lesser duration and intensity of the monsoon there should result in lower LB pressure with a June/July planting.
Planting just prior to the monsoon in highland areas with annual rainfall < 1000 mm has given outstanding yields with cvs Achirrana Inta and I-1124. On-station and farmers' field trials have produced over 40 and 30 T ha-1, respectively, more than 4x the national average yield and nearly 2x the equivalent yield for a normal season planting in the same site. The LB resistant cultivars and the new cropping pattern may be extended to similar sites. (Supported by Swiss Devel. Assistance & Humanitarian Aid, Bern, Switzerland)