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