Agronomic performance and genotype x environment interaction analysis of 12 elite potato genotypes in Uganda

High yielding potato (Solanum tuberosum) genotypes with good levels of resistance to late blight were identified at Kalengyere Research Station in southwestern Uganda. The yield stability of these genotypes, however, remains uncertain. For instance, the performance of these genotypes varied over 4 seasons of evaluation and when tested at Kachwekano site. Genotype x environment interaction study was therefore required to determine their adaptation in the different agroecologies where the genotypes would be grown. Five sites in Uganda at different elevations were selected for the study and these were Kalengyere (2450 masl), Bulegeni (1670 masl), Mbarara (1500 masl), Tororo (1250 masl) and Namulonge (1150 masl). The trials were conducted for three seasons: namely 2000 (A and B) and 2001 (C) being the first (A) and second (B) and third (C) seasons of the trials. Each location for a particular season was regarded as one environment. Genotypes 389484.20, 389685.2, 389698.12, 389584.22 and 389701.34 performed better than the other genotypes in all the five locations. The G x E analysis was done using Additive Main effects and Multiplicative Interaction (AMMI) and the biplot identified genotypes 389484.20, 391558.16, Victoria, 391558.5, 389584.22, Kisoro and 391558.13 as adapted to Bulegen C, Mbarara B, Namulonge B and C and Tororo A, B and C. Genotypes 391558.11, 389685.2 and 391558.1 were adapted to Kalengyere A. Namulonge B and C and Tororo A, B and C were identified as similar environments basing on their responses.