Comparação de métodos para avaliar a adaptabilidade e estabilidade produtiva em algodoeiro

Abstract

Comparison of methods for the evaluation of adaptability and stability for yield in cotton genotypesAbstract -The objective of this work was to compare different methods used to estimate adaptability and stability of 17 cotton genotypes evaluated in 23 locations of the Brazilian savannah. Genotype and environment effects and genotype x environment interaction were significant. According to ecovalence and AMMI models, cultivar BRS Cedro showed the best stability. Varieties Delta Penta and BRS Ipê were among the most unstable genotypes, but not among the most productive. Using the methods of Eberhart & Russel, Lin & Binns and Annicchiarico, genotypes BRS 269 -Buriti, FMT 701 and CNPA GO 2001-999 were the most stable and among the five most productive on average. The evaluation of the specific adaptabilities provided by the AMMI analysis is of great importance in the study of the behavior of genotypes. The amount of information generated and the facilities of interpretation favors Lin & Binns method, which can be complemented by an AMMI analysis.Index terms: Gossypium hirsutum, AMMI analysis, assesment of cultivars, ecovalence, genotype x environment interaction. IntroduçãoNo Brasil, o algodoeiro (Gossypium hirsuntum L.) é cultivado em toda a faixa tropical, e a região do Cerrado se destaca tanto em área cultivada quanto em produtividade. Contudo, dada a extensão dessa região, condições diferentes de clima e solo são encontradas e, portanto, é esperada ausência de comportamento consistente de genótipos nos diversos ambientes.A identificação de cultivares com maior estabilidade fenotípica é uma das estratégias para amenizar o efeito da interação genótipos x ambientes (GxA).A metodologia denominada de ecovalência, proposta por Wricke, citado por Cruz & Regazzi (1997), decompõe a soma de quadrado da interação em partes atribuídas a cada genótipo, e considera como mais estável o genótipo que apresente menor estimativa para a ecovalência. Ramalho et al.(1993) comentam que a ecovalência é

Performances agronomiques et stabilité phénotypique de génotypes de Sorgho (<i>Sorghum bicolor</i> (L.) Moench) au Sénégal: une étude des interactions génotypes-environnement

“…Les très faibles adaptations de IS15401 et SK5912 aux environnements S13D2 et S14D2 pour la biomasse pourraient être imputées d'une part aux dates de semis tardives et d'autre part à la faible pluviométrie enregistrée dans ces environnements. La possibilité d'identifier des génotypes stables et des génotypes avec des adaptations spécifiques à certains environnements constituent un avantage important de la méthode AMMI comparativement aux autres méthodes couramment employées (Silva Filho et al, 2008).…”

Evaluation of sugarcane genotypes and production environments in Paraná by GGE biplot and AMMI analysis

“…Recently, several methods were used simultaneously to evaluate genotypes and production environments of different crops (Silva and Duarte 2006, Cargnelluti Filho et al 2007, Melo et al 2007, Silva Filho et al 2008, Pereira et al 2009, Guerra et al 2010, Nunes et al 2011, Gouvêa et al 2011). However, the AMMI has seldom been used together with the GGE Biplot in studies on sugarcane.…”

Environmental stratification in cotton in the presence or absence of genotypes with high ecovalence

“…Cottonseed yield data obtained from 17 cotton cultivars evaluated in 23 locations in the Brazilian Cerrado were used in this study (Silva Filho et al 2008). The ecovalence of two cultivars, BRS Ipê and Delta Penta, hereinafter referred to as high ecovalence cultivars (HEC), contributed for more than 30% of the sum of squares of the GEI (Table 1).…”