Heterosis and Combining Ability of Fruit and Bean Characters in Ethiopian Origin Coffee (Coffea arabica L.) Hybrids

A half diallel analysis involving five parents, ten F1 hybrids and one check hybrid was studied for fruit and bean traits to generate information on heterosis and combining ability. The genotypes were evaluated in a randomized complete block design (RCBD) with three replications at Melko, Metu and Tepi research centers. The analysis of variance revealed highly significant difference among genotypes at (p<0.05) for all fruit and bean characters. This consistent significant difference for different traits suggests the presence of genotypic difference among parental lines and hybrids evaluated. Majority of fruit and bean characteristics showed negative heterosis over mid-parent and better-parent values. This may generally suggesting dominance of the small sized fruit and bean character over large sized parents. Both the additive and non-additive gene actions were involved in the control of the characters studied for fruit length, fruit width, fruit thickness, bean length, bean width, bean thickness and 100-bean weight. Keywords: Heterosis, Combining ability, Gene action, GCA, SCA