GENOTYPE X ENVIRONMENT INTERACTION, STABILITY AND CO-HERITABILITY OF TUBER INTERNAL QUALITY TRAITS IN POTATO CULTIVARS IN ETHIOPIA

Potato (Solanum tuberosum L.) is a crop with the potential of ensuring food and nutrition security in Ethiopia because it yields more edible energy, protein and dry matter per unit area and time than cereal crops. In Ethiopia, potato varieties were developed mainly to fit preparation of traditional foods. However, French fries and chips are the emerging products of tubers that demanded breeders to identify cultivars fit to the emerging economics of production until specific varieties are developed for specific end products. This study was conducted with the aim of identifying wide adaptable potato varieties for internal quality of tubers, and to determine stability, coheritability and correlation among traits. A total of 17 improved and two farmers' cultivars namely, Jarso and Bete were evaluated in three locations from 2012 to 2014 using a randomized complete block design with three replications. Specific gravity and starch content of tubers were significantly influenced by the interaction of cultivar x location x seasonwhile dry matter was significantly affected only by cultivar, location and growing season. The 15 improved varieties produced tubers with >1.08 [gcm.sup.-3],>23% and >13%specific gravity, dry matter and starch content, respectively, that were suitable for French fries and chips processing, but the two farmers' cultivars (Jarso and Bete) with tubers