P. Ntawuruhunga, P. Rubaihayo, J.A.B. Whyte, D.S.O. Osiru and A.G.O. Dixon
A crop’s ability to productively exploit its environments depends on many features which are controlled by multiples genes interacting among themselves and with the environments in complex ways. A study of cassava (Manihot esculenta Crantz) adaptation was conducted at three different land altitudes (Bulisa, Namulonge and Kapchorwa at 650, 1150 and 1750 m a.s.l respectively) in Uganda. Ten cassava genotypes originated from 5 different sources were used in randomized complete blocks design in three replications at each location. The aim of the study was to investigate the performance of cassava at different altitudes. Some of the parameters evaluated are plant height, tuberous root number, fresh weight and cyanogenic potential (Cnp). The results indicated a highly significant source, clone (source), location and clone (source) x location interaction for the parameters evaluated, with the clones SS4 producing the highest yields at low (Bulisa) and mid land altitude (Namulonge) while it was the clone TMS I 92/0067 better yielding in the high land altitude. Across the three locations the clone well yielding was TMS I 92/0057. The yield was highest in the low land (Bulisa) while it was low at high land altitude (Kapchorwa). The clones and sources reacted differently to locations. Clones from source 1 (low land altitude from Uganda) failed almost to sprout in the high land altitude. The clone TMS I 92/0057 was the tallest over locations. Clones Migyera followed by TMS I 92/0067 produced high number of tuberous root per plant in both locations, mid and high land, while it was the other way round in the low land altitude, TMS I 92/0067 followed by Migyera. Overall they produced 9.8 and 9.3 tuberous number per clone while clone Eala 07 produced the least (3.5). The coefficient stability parameter used indicated variation between genotype coefficient for the genotypes tested and clone TMS I 92/0057 was identified the highest yielding and stable. No effect due to altitude was identified on cyanogenic potential in cassava.