| dc.description.abstract |
Knowledge of the effects of environment and genotype by environment (GxE) interaction is important to breeders in making decisions regarding the release of new cultivars. Five Coffea arabica lines coded CR8, CR22, CR23, CR27 and CR30 have been developed by Coffee Research Foundation and are currently being tested for release in various coffee growing zones in Kenya. The objective of this study was to determine the performance of the five advanced breeders’ lines under varying environment and spacing. Two commercial Arabica cultivars, SL28 and Ruiru 11 were included in the study as check cultivars. The trial was established during the long rain season of
March/April 2007 at Kitale in Western Kenya and Meru in Eastern Kenya. The experiment was laid out in a Randomized Complete Block Design (RCBD) with 10 trees per plot planted at spacing of 2 m x 1.5 m and 2.75 mx 2.75m and replicated three times. Growth and yield data were recorded at the end of the first and second year after field establishment. The data were subjected to analysis of variance. Duncans Multiple Range Test (DMRT) was used to separate significantly different means at P = 0.05. Data were further subjected to cluster and principle component analyses. Significant
environment effect was observed on all variables. Closer spacing promoted
better expression of the variables than wider spacing, except for length of the
longest primary and internode length. The years were also significantly
(P<0.05) different with all parameters being more pronounced in the second
year (2009) than in first year (2008), except the internode length on primaries
where the case was vice versa. Correlation between the main growth
characters and yield characters was significant (P<0.0001). The study
confirmed that the new lines were better or similar to existing varieties and
therefore the breeding objective was achieved. Lack of genotype by
environment interaction indicated the stability of the genotypes. |
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