Use of additive main effects and multiplicative interaction models to analyze multilocation rice variety trials

摘要

The usual additive effects model has long been used to analyze genotype and environment effects in international variety trials but it fails to offer insight into genotype-environment (GxE) interaction. Additive main effects and multiplicative interaction (AMMI) models provide insight into the environmental factors accounting for GxE interactions when analyzed in conjunction with environmental measurements. They can also improve the precision of estimation of genotype and environment effects and provide insight into stability and selection potential for the varieties. These characteristics of AMMI models is illustrated in the analysis of data from the 20th International Irrigated Rice Yield Nursery for Early maturing varieties from the International Network for Genetic Evaluation of Rice (INGER), which is coordinated by the International Rice Research Institute (IRRI). Results of the analysis indicate that sites in Southeast Asia are very similar with respect to adaptation of the test entries compared to sites in other regions. Hence, they could be reduced in favour of more discriminating sites. Genotypes tested interacted with low temperatures, nutrient status, and latitude. The latter indicating photoperiod sensitivity which was not thought to be present in these varieties. Adaptability domains are defined for the tested varieties and the AMMI model is Used to indicate the best adapted varieties for these domains.