A study of the ecological variability in yield of selected clones of Arabica coffee (Coffea arabica L.) from the coffee-breeding programme in Kenya
Cherry yield of eleven elite clones of Arabica coffee was evaluated over a five-year period at Upper Kiambu, Makuyu and Kisii in Kenya, in a continuing study to determine the extent and influence of clone x environment interactions on coffee breeding lines developed in Kenya. Clone mean yield comparisons indicated a better performance of all the improved clones compared with the control. In an analysis of variance, significant main effects and non-significant clone x environment interactions (P minor who 0.05) were found. Interactions were however, further investigated using ecovalence values, the Eberhart and Russell (1966) regression model as well as the Additive Main effects and Multiplicative Interaction effects model. The clones were then clustered according to their response patterns using principal components and cluster analyses to obtain a delineation of ecological districts and more accurate predictions of clone performance. The main effects for clones reflected breeding advances with the standardvariety having the smallest mean. Improved materials from the hybridization scheme appeared to do better than their pure line counterparts with clones 8, 3, 1 and 2 being the most advanced of the 11 clones. Similarly, the main effects for the environmentreflected the overall site/year quality with Kiambu having the best production conditions particularly due to the favourable weather in 1983. This indicates that the coffee growing upper zone may be favourable for the clones especially when they are raised by top-working old coffee. Makuyu environments had the least interaction effects.
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| Format: | biblioteca |
| Published: |
2001
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| Subjects: | COFFEA, COFFEA ARABICA, CLONES, CAFE, RENDIMIENTO DE CULTIVOS, IMPACTO AMBIENTAL, MODELOS, KENIA, |
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