CROP SCIENCE, VOL. 54, JULY– AUGUST 2014 WWW.CROPS.ORG 1 RESEARCH W heat is grown under diferent environmental conditions, especially with regard to water availability, soil, and weather conditions. Genotype by environment interaction is a measure of the diferentiated response of genotypes to the varied environmen- tal conditions. The GEI is the main cause of variability in wheat yield performance of diferent environments in Brazil. Brazilian Spring Wheat Homogeneous Adaptation Regions can be Dissected in Major Megaenvironments Lucas Berger Munaro, Giovani Benin,* Volmir Sérgio Marchioro, Francisco de Assis Franco, Raphael Rossi Silva, Cristiano Lemes da Silva, and Eduardo Beche. ABSTRACT The objectives of this study were to investigate the pattern of genotype environment interaction and identify megaenvironments (ME), essential test locations, and suitable genotypes for each ME. The genotype plus genotype by environ- ment interaction (GGE) biplot and additive main effects and multiplicative interaction analysis (AMMI) were used to demonstrate the potential of using a graphical biplot to analyze the geno- type by environment interaction (GEI) in data of multienvironment trials (MET). These trials of the Central Cooperative Agricultural Research (COODETEC) evaluated 36 advanced breeding lines and 27 check cultivars for 3 years (2008– 2010) at 12 test locations. Yield data were ana- lyzed using the genotype plus GGE and AMMI biplot methods. The test environments were classiied into two ME (i.e. ME1: Castro, Gua- rapuava, Não-Me-Toque, Abelardo Luz, and Cachoeira do Sul; and ME2: Campo Mourão, Dourados, Palmital, Palotina, Ponta Porã ,and Rolândia. In ME1, the locations Guarapuava, Cachoeira do Sul, and Abelardo Luz were clas- siied as ideal, while in ME2, Ponta Porã, Dou- rados and Palotina were close to ideal. Guar- apuava was the essential test location in ME1; however the identiication of an essential test location in ME2 was unclear. Superior cultivars and advanced lines were identiied in both ME that could be valuable for spring wheat (Triticum aestivum L.) improvement or cultivars released. L.B. Munaro, G. Benin, R.R. Silva, C.L. da Silva, and E. Beche, Universidade Tecnológica Federal do Paraná (UTFPR), PR 469, km 01, 85501-970, Pato Branco, PR, Brazil; V.S. Marchioro and F.A. Franco, Cooperativa Central de Pesquisa Agropecuária (COODETEC), BR 467, km 98, 85813-450, Cascavel, PR, Brazil. Received 4 June 2013. *Corresponding author (benin@utfpr.edu.br). Abbreviations: ABL, Abelardo Luz; AEC, average environment coordinate; AMMI, additive main efects and multiplicative inter- action analysis; CDS, Cachoeira do Sul; CMR, Campo Mourão; COODETEC, Central Cooperative Agricultural Research; CSC, Cascavel; CST, Castro; DRD, Dourados; E, environment main efect; G, genotype main efect; GEI, genotype by environment interaction; GGE, genotype plus genotype by environment interaction; GVA, Guarapuava; IPCA, interaction principal component axis; ME, megae- nvironment; ME1, Megaenvironment 1 (Castro, Guarapuava, Não-Me- Toque, Abelardo Luz, and Cachoeira do Sul); ME2, Megaenvironment 2 (Campo Mourão, Dourados, Palmital, Palotina, Ponta Porã ,and Rolândia); MET, multi-environment trials; NMT, Não-Me-Toque; PC, principal component; PMT, Palmital; PTN, Palotina; PTP, Ponta Porã; RLD, Rolândia; SVP, singular value partitioning; VCU, value for cultivation and use; VCU1, VCU region 1 (cold, humid, and high elevation); VCU2, VCU Region 2 (moderately hot, humid, and low elevation); VCU3, VCU Region 3 (hot, moderately dry, and low eleva- tion); VCU4, VCU Region 4 (hot and dry). Published in Crop Sci. 54:1–10 (2014). doi: 10.2135/cropsci2013.06.0365 © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Published June 6, 2014