Apresentaram-se estimativas das capacidades geral e específica de combinação e suas respectivas somas de quadrados, obtidas num sistema dialélico parcial desbalanceado. Avaliou-se, como ilustração, a capacidade. combinatória de dois conjuntos hipotéticos de dados provenientes de um dialelo envolvendo progenitores e respectivos F1s e de outro envolvendo apenas os F1s.Estimates on general and specific combining abilities as well as their corresponding Sums of squares were obtained from unbalanced partial diallel systems in which progenitors and/or hybrid combinations were evaluated with an unequal number of replications. As an illustration, the hypothetical data sets of a diallel involving progenitors and the corresponding F1s and another involving only the F1s were analysed.