G x E interactions, heritability estimates and varietal adaptability in important agronomic characters of cassava [Manihot esculenta]
1984
Tan, S.L.
The combined analyses of variance on a series of six trials testing 16 germplasm varieties of cassava at five locations resulted in highly significant G x E interactions for all important agronomic traits. Hoever, relative to the genotype variance component, the G x E componentwas only important in determining germination, root yield, harvest index, commercial root number and starch yield. Broadsense heritability estimates derived from from variance components suggest that characters which showed a smaller G x E interaction as well as a small environment variance component were more highly heritable than not. By this definition, total root number and starch content were highly heritable traits. Stability analyses on varietal performance identified Bangkok 1 as the most stable variety among the top five starch yielders. All other high-yielding varieties were rated unstable, whereas Buluh, a low-yielder, proved most stable. The results suggest that, in conjunction with stability parameters, overall mean yield (over environments) is still an important criterion in the selection for adaptability of cassava varieties. Most varieties with high starch contents in their roots were stable for this trait.
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