Use of GGE biplot for targeting early maturing maize cultivars to mega-environments in West Africa

Maize ( Zea mays L.) is an important staple food consumed by people with varying food preferences and socioeconomic backgrounds in West Africa (WA). Genotype by environment interactions (G×E) exist in WA implying the need for extensive testing of cultivars in multiple environments over years before cultivar realistic recommendations can be made. This study examined the effect of G×E on the performance and stability of early cultivars and to identify core test locations in the mega-environments of WA. Across locations, 2004 TZE-W Pop STR C4 produced the highest grain yield and was the most stable cultivar. DMR-ESRW QPM produced the lowest yield. The test environments contributed about 83.4% of the total variation in grain yield, while genotypes accounted for 1.5% and G × E, 11%. Test environments were classified into four mega-environments, namely, Katibougou, Sotouboua, Ejura, and Bagou as the first group; the second group consisted of Manga, Nyankpala, Bagauda, Yendi, Angaredebou, Mokwa, Katibougou, and Zaria; while the third group comprise of Ativeme, and Ikenne; and the fourth, Ina. Test locations Ejura, Sotouboua and Bagou and Katibougou were highly correlated in their ranking of the genotypes in group 1, suggesting that a promising early maturing cultivar selected in one of these locations in one country will also be suitable for production in the other locations within the same mega-environments in different countries. Kita was identified as the ideal location, while Zaria was close to the ideal location. Key Words: Genotypes, multiple environment, Zea mays