GENOTYPE-ENVIRONMENT INTERACTION IN TROPICAL MAIZE VARIETIES DEVELOPED FOR THE TROPICAL REGION OF VERACRUZ, MEXICO

In the humid tropics of Mexico, maize (Zea mays L.) improved varieties with desirable plant agronomic characteristics and grain quality protein are required. The synthetic varieties of maize are adequate for rainfall agriculture the farmers do not need to buy seeds every year. In order to identify the best synthetics with high grain yield and lower genotype-environment interaction (GEI), eight maize synthetic varieties were evaluated in four sites of the State of Veracruz, Mexico, during 2009, 2010 and 2011. A randomized complete block design with two replications was used. The GEI effect was estimated by using the model of additive main effects and multiplicative interaction (Ammo. Results showed that the two main principal components (PCA) of the model AMMI had not significance (P >= 0.05); however, accumulatively they contributed 73% of the total variation. The variance due to environments was greater than that due to genotype differences. According to PCA1, the 'synthetic-2' had a more stable behavior. The AMMI model allowed grouping the environments in two relatively homogeneous groups: the first one formed by the environments E2 and E3, and the second, by E1 and E4. The biplot technique was used to identify genotypes for general or specific adaptability. In conclusion, there were different responses among the synthetic varieties evaluated in the environments, and little association among the high grain yielding varieties and the more productive environments. The best grain yielding genotypes are appropriate to further develop a better variety or to develop inbred lines to form better maize hybrids.