Submitted to: Experimental Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2007
Publication Date: 4/15/2008
Citation: Mulema, J.M., Adipala, E., Olanya, O.M., Hakiza, J.J. 2008. Yield stability analysis of late blight resistant potato selections. Experimental Agriculture. 44:145-155. Interpretive Summary: Prediction of the performance of potato genotypes in tropical environments are often confounded by the genotype by environment interactions as well as the diversity of potato-based cropping systems. Clones from population B selections with quantitative resistance were grown in replicated field experiments in Uganda. The additive main effects and multiplicative interactions (AMMI)model was used in identifying the performance of superior genotypes. Based on the analysis, several potato clones with high yield levels and superior performance in various tropical environments were identified. These can be used to increase potato yield by the growers.
Technical Abstract: The identification of superior potato genotypes is complicated by genotype by environment (G x E) interactions, making prediction of performance difficult. The additive main effects and multiplicative interaction (AMMI) model was therefore used to identify performance of elite population B potato selections grown at different locations in Uganda, and to estimate genotype performance by removing G x E interaction. The results of the combined analysis of variance showed significant (P<0.001) effects of environments, genotypes and G x E interactions. The highest yield (40.3 t/ha) was recorded in 2002B and the least in 2002A (21.7 t/ha). The Kachwekano 2002B site recorded the highest yield (52.3 t/ha) and Mbarara 2002A had the lowest (3.2 t/ha). The potato clone 381471.18 had the highest yield (43.1 t/ha) and the least tuber yields were obtained on 392127.256 (22.7 t/ha) and 391049.255 (22.6 t/ha). The high yielding potato clones 392618.250 and 392127.270 and low yielding clones 392618.256, 391049.255 and 392127.256 had negligible interactions with the environments indicating their broad adaptation. Although potato clones 381471.18, 387121.4 and the variety Victoria were high yielding, they had high principal component score (IPCA1) values and are therefore unstable.