POTATO IMPROVEMENT IN UGANDA
The importation of blight-resistant lines and tests for blight resistance began in 1943, at the former Scott Laboratories in Nairobi (Cox & Large, 1960). Most of the work in Kenya has centred around Black's R-gene resistant hybrids, imported from Scotland. One of Black's seedlings, B-53, proved to be resistant to the prevalent races of Phytophthora infestans and was widely distributed in Kenya, replacing older blight-susceptible varieties such as 'Kerr's Pink', 'Dutch Robijn' and others.
The entire potato crop in Uganda is produced by subsistence cultivators and control of 'Late Blight' by spraying is therefore not feasible for most farmers. The only practical approach to increasing potato yields in Uganda appears to be through the use of high yielding blight-resistant varieties. Potato varieties which have been introduced into Uganda in the past apparently become more susceptible to the disease; this could be an indication of the extreme pathogenic variability of Phytophthora infestans. This loss of resistance emphasises the need for a survey of the pathogenic races present in Uganda so that breeders can identify the type of resistance which should be incorporated in new varieties (Gallegly, 1969).