The utilization of true potato seed (TPS) as an alternative method of potato production

Potato is grown as a rainfed and irrigated crop in the cooler highlands and mid-altitude regions of the tropics. Its productivity is very low mainly due to unavailability of healthy and sufficient amount of seed potatoes to the farmers. The utilization of true potato seed (TPS) can be considered as an alternative method to produce potatoes, thereby alleviating the problems associated with seed potatoes.The first aim of the research report in this thesis was to study problems related with poor TPS germination. The second aim was to determine the best growing season to grow TPS for seedling tuber production. The third aim was to develop appropriate seed bed management practices for maximum seedling tuber production.Increasing nitrogen fertilization to the mother plant enhanced the rate of gerniination of the TPS of the open pollinated progeny (AL 624) and reduced that of the hybrid progeny ( AL 624 x CIP 378371.5) without affecting the final germination percentages (FGP) of both progenies.TPS dormancy was effectively broken by soaking in 1000-1500 ppm GA 3 for 8 hrs. Treating TPS with water can also break dormancy and maintain about 70 % germination. The latter may be considered as a cheap, readiliy available and practical alternative method of breaking TPS dormancy under farmers' condition.The field and nursery experiments indicated that seedling tuber yields are very low during the rain season due to late blight ( Phytophthora infestans ) pressure, shorter sunshine hrs and a shorter growing season than the dry season.Based on the nursery results, in the central highlands of Ethiopia, dry season production of seedling tubers in a seed bed substrate mix of 50 % forest soil and 50 % manure, and 40 - 80 g N per m 2bed were found to be suitable for the production of a maximum number of seedling tubers by direct sowing methods.Manipulation of seedling population in a seed bed is one method of producing a maximum number of usable seedling tubers. The results revealed that a plant density of 100 plants per m 2seed bed was optimal for the production of a maximum number of up to 1200 seedling tubers or a total tuber weight of 29 kg per m 2without hampering management operations such as weeding, fertilization and billing up.The research results showed that there is a considerable potential of alleviating the problems of seed potatoes by improving the TPS germination quality, seed bed production of seedling tubers and using them as seed potato source for subsequent growing seasons.