Genotype X Environment Interaction Effects on the Developmental Time, Kernel Modification and Yield of Experimental Quality Protein Maize (Zea mays L.) hybrid Varieties
Shava, Justify Gotami
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Genotype „e environment interactions occur in crops grown in more than one environment such that it is unusual for a single genotype to perform better than other genotypes at all the locations in which they are grown posing a challenge to breeders who must either develop genotypes with broad or specific adaptation. An investigation into the effects of genotype „e environment interactions on grain yield, kernel modification, plant height, ear height, ear position, number of ears per plant, grain texture, days to 50 % anthesis and 50 % silking, and the anthesis¡Vsilking interval for 24 Quality Protein Maize (QPM) hybrids plus one normal check grown at five locations, ART Farm, CIMMYT Low N, Kadoma Research Station, Rattray Arnold Research Station and Shamva was carried out in 2006/7. The experiment was a 5 „e 5 alpha Lattice design with two replicates at each location. The mean location grain yield ranged from 1.6 t/ha at Kadoma Reasearch Station to 11.104 t/ha at Art Farm. Genotype „e environment interactions were significant (P<0.05) for plant height, but not for grain yield, kernel modification, days to 50 % athesis and 50 % silking, number of ears per plant and anthesis¡Vsilking interval (P = 0.05). The ¡§which-won-where¡¨ GGE biplot showed that genotypes 1150 (A7/A), 1172 (A8/A), 1361 (A11/A), 791 (A10/B) and 1345 (A10/A) outperformed other genotypes in terms of yield at Art Farm; 791 (A10/B), 1361 (A11/A), 1003 (A1/A), 1345 (A10/A) and 389 (A4/B) outperformed others at CIMMYT Low N; O6t 359 (A3/B), 865 (A9/B), 1345 (A10/A), 1141 (A6/A) and 507 (A6/B) won at Kadoma Research Station, O6t 1361 (A11/A), 359 (A3/B), 1479 (A12/A) and 955 (A12/B) won at Rattray Arnold Research Station while O6t 359 (A3/B), 1003 (A1/A), 1361 (A11/A) and 466 (A5/B) won at Shamva. O6t 389 (A4/B), 865 (A9/B), 307 (A1/B), 1479 (A12/A) showed broad adaptation across the five locations tested. There were no significant relationship between grain yield and number of ears per plant (R2 = 0.1041), plant height (R2 = 0.341) and anthesis-silking interval (R2 = 0.0059). An index of selection that incorporated kernel modification and grain texture indicated that the environments, genotypes and the genotype ¡Ñ environment interaction were all significant (P<0.05) suggesting that this index may be used in future QPM breeding for selecting simultaneously for kernel modification and grain texture. The testers were not significantly different from each other on their effect on grain yield when crossed to each of the lines A1 ¡V A12 used to form those hybrids. However, lines and the locations were significantly different (P < 0.05).