GENOTYPE-ENVIRONMENT INTERACTION OF YIELD AND GRAIN AND TORTILLA QUALITY OF MAIZE HYBRIDS AT THE HIGHLANDS OF TLAXCALA, MÉXICO

Abstract

Currently, the low productivity of maize (Zea mays L.) in the central highlands of México is due to adverse environmental conditions such as drought, higher than usual temperatures and early frosts. To increase productivity, it is necessary to develop stable maize varieties with high yield which can meet the quality characteristics of grain, nixtamal and tortilla demanded by the processing industry. In this study, we determined the effect of the genotype x environment interaction on grain yield and on the physical traits of grain, nixtamal and tortilla of 20 pre-commercial and commercial maize hybrids, grown during the 2009 harvest season in six locations in the highlands of Tlaxcala, México. Grain yield, test weight, 100-grains weight (HGW), flotation index (FI), color of grain and flour, and nixtamal and tortilla quality were evaluated. The results for grain yield and grain physical traits were statistically analyzed using the model of additive main effects and multiplicative interactions (AMMI), while data of nixtamal and tortilla quality were analyzed under a completely randomized design. The AMMI model provided a good description of the genotype x environment interaction and stability of the 20 hybrids. Both planting conditions and environment induced changes on the physical characteristics of hybrids, especially the grain size and hardness. Tlatempa and Huamantla were the best localities for yield (9.8 y 8.3 t ha^-1), grain size (HGW > 33 g), hardness (FI < 40 %) and tortilla quality. Nicolás Bravo, Emiliano Zapata and San Bartolomé Cuahuixmatlac were the most adversely affected sites in terms of yield (3.8, 4.3, 2.6 t ha^-1), grain size and hardness (HGW < 33 g, FI > 60 %). Fifteen hybrids met the specifications for masa and tortilla industry but none met the specifications for nixtamalized flour industry.