Genotype*environment interaction in maize grown in Tamaulipas, Mexico

Abstract

In northern Tamaulipas, Mexico between 30 000 and 100  000 hectares with maize (Zea mays L.) are grown each year.  The surface varies due to the incidence of biotic factors  (insect pests, toxigenic fungi) and abiotic factors (high  temperature, soil salinity, drought), as well as the availability  of water for irrigation. For this reason, cultural, genetic,  biological and chemical alternatives for crop management  must be constantly evaluated to maximize yield and grain  quality. In this paper, the agronomic behavior and genotype  x environment interaction of eight maize hybrids planted at  four sowing dates and three years of cultivation based on the  analysis of the interaction of main and additive main effects  (AMMI) and model Genotype, genotype x environment  (GGA) Biplot were evaluated; as well as in sequential trail  analysis (ASS). The AMMI analysis for grain yield indicated  significant differences (p≤ 0.01) between hybrids and test  environments. Main components analysis indicated that  the first two components (CP) contributed 76% of the total  variance (PC1= 20 and PC2= 56%); the GGE biplot analysis  indicated that DK-697 was the hybrid with higher yield and  greater stability. The biplot graphic showed that the vectors were further away from the center for year 2006A, 2006B,  2006C and 2007A (greater interaction and genotyping  ability), while the nearest vectors were 2008B and 2008C  (lower interaction). Among hybrids, the most remote from  the origin (less stable) were H-437 and G-8222; the closest  to the origin and more stable was DK-697. The ASS analysis  detected moderate colinearity for all evaluated characteristics,  with strong effects of the number of healthy cobs (Influence  Value of Variance or FV= -1.41) and cob weight (FV= -1.19).  The variables with the greatest association to grain yield were  cob weight, plant height, plant height/cob ratio and number  of healthy cobs explaining 86% of the variation.