Biplot evaluation of test environments and identification of mega-environment for sugarcane cultivars in China

Test environments and classification of regional ecological zones into mega environments are the two key components in regional testing of sugarcane cultivars. This study aims to provide the theoretical basis for test environment evaluation and ecological zone division for sugarcane cultivars. In the present study, sugarcane yield data from a three-year nationwide field trial involving 21 cultivars and 14 pilot test locations were analysed using both analysis of variance (ANOVA) and heritability adjusted-genotype main effect plus genotype-environment interaction (HA-GGE) biplot. The results showed that among the interactive factors, the GE interaction had the greatest impact, while the genotype and year interaction showed the lowest impact. Kaiyuan, Lincang and Baoshan of Yunnan, Zhangzhou and Fuzhou of Fujian, and Hechi, Liuzhou and Chongzuo of Guangxi, and Lingao of Hainan were ideal test environments with a demonstrated high efficiency in selecting new cultivars with a wide adaptability, whereas Baise of Guangxi was not. Based on HA-GGE biplot analysis, there are three ecological sugarcane production zones in China, the Southern China Inland Zone, the Southwestern Plateau Zone, and the Southern Coastal Zone. The HA-GGE biplot analysis here presents the ideal test environments and also identifies the mega-environment for sugarcane cultivars in China.