HETEROSIS IN CROSSES OF INDIGENOUS COFFEE SELECTED FOR YIELD AND RESISTANCE TO COFFEE BERRY DISEASE-FIRST BEARING STAGE

Two high-yielding coffee Coffea arabica L. lines and three lines selected for resistance to coffee berry disease caused by a fungus Colletotrichum coffeanum Noack were crossed in a half-diallel to produce ten hybrids.
The hybrids were grown at Melko, Jimma Research Station.

The F₁s exhibited positive mean midparent and high-parent heterosis from 7.5 to 21.9% and from 2.3 to 5 %, respectively for girth, number flowers and fruits and length of first primary branch and the hybrids 1 x 5 and 3 x 5 exhibited high-parent heterosis from 10 to 12 % for girth; 16 to 23 % for number of flowers and fruits; 9 to 10% for length of first primary branch; 11 to 12 % for number of primary nodes and 8 to 10 % for number of bearing primary nodes and were highly significantly superior to their respective high-parent for many of the above characters followed by 3 x 4 and 1 x 4 hybrids.
Midparent heterosis -33 to 5 % was noted for number of secondary branches.

The correlation analysis of characters in F₁s detected significant correlations (r=0.79 and 0.82) between growth and girth and growth and number of primary nodes.

The significant F₁ heterosis and SCA of 1 x 4,1 x 5, 3 x 4 and 3 x 5 indicated the possible desirability of F₁ hybrids to maximize yield in these material.

Fruit Breeding, XXI IHC

M. Ameha

https://doi.org/10.17660/ActaHortic.1983.140.20