Heterosis in Crosses of Indigenous Coffee selected for yield and resistnace to Coffee Berry Disease:II- First Three Years.
1983
Mesfin Ameha and Bayetta Belachew(Plant Breeder and Agronomist,Assistance Research Officer in Coffee Breeding, Respectively)
Two high yielding coffee (Coffea arabica L.) lines and three resistant Iines to coffee berry disease were crossed in half diallel to produce ten hybrids. The hybrids were grown at Meiko, Jima Research Station in four replications. Mean yield of three consecutive years were evaluated for the presence of heterosis. Combining ability analysis indicated that on the average line 741 and F59 expressed greater combining ability effect but the array mean -f F59 was the largest than the rest of the lines. Further investigation showed that the specific cornbining ability variance was the largest for F59 followed by 2970 as compared to others. The combination F59 x 7395 expressed the largest specific combining ability than the rest of F1s . The hybrids exhibited positive mean heterosis over high-parents for yield except in 7332 x 7395 crosses. Highly significant yield heterosis of 60% and 36% were expressed in crosses between 741 x 2970 and 7395 x 2970, respectively, and significant yield heterosis of 20% was expressed in crosses between 7395 x F59. The favourable hybrid 741 x F59 exhibited 18% heterosis over F59 the high yielding parent but stands second to 7395 x F59 in mean yield. The significant yield heterosis together with the significant heterosis for components of yield and the abilities of the high yielding lines to transmt their yielding capacities to a number of Iznes avoids the fear to exploit the advantage of hybrid vigour for yield.
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