Genotype by Environment Interactions in Maize in Eastern Africa

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Penny, L.H.
Eberhart, S.A.
Harrison, M.N.
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37 environments in 1968-69. A large proportion of the genotype by environment interactions could be explained. by differential responses among varieties to altitude and to environments. Because temperature is highly oorrelated with altitude in East Africa, the altitude response may be primarily a temperature response. Days to tassel increased an average of 21.8 days per km. of increased altitude with a range of 17.7 to 23.7 days per km. The average increase in yield was 17 q / ha. per km. with arrange of 3.5 to 27.9 q/ha. per km. Varieties that involved high-altitude source material and those that had been selected at high altitudes yielded relatively better at higher altitudes than varieties that involved low-altitude source material and yielded nearly as well as low altitude varieties at low and medium altitudes. Predicted yields for an Eastern African location obtained with the parameters mean yield, response to altitude (bA), and response to the environmental index WI) estimated from extensive regional trials should be more reliable than observed results from a limited number of trials at that location. The current commercial varieties and recently developed experimental material seem to be adapted throughout Eastern Africa within the appropriate altitudinal zone with the permission of the Director, East African Agriculture and Forestry Research Organization.
East African Agricultural And Forestry Journal, XXXIX (No 1), pp. 61-71