Adaptability and Phenotypic Stability of Lettuce Cultivars in a Semiarid Region

Abstract

Studies on lettuce genotypes growing in different environments and planting seasons are important for this crop because its productive potential is greatly affected by environmental conditions. The mixed model methodology (REML/BLUP) have been used to evaluate the effects of the genotype-environment interaction on crops. Thus, the objective of the present work was to estimate parameters of adaptability and the phenotypic stability in lettuce cultivars grown in a semiarid region of Brazil, using a mixed model. Twelve lettuce cultivars from the Americana (Angelina, Amélia, and Tainá), Crespa (Scarlet, Vera, Isabela, and Vanda), Mimosa (Mila, Mimosa, and Lavínia), and Lisa (Elisa and Regiane) groups were evaluated. The experiments were conducted in a randomized complete block design, with four replications. The genetic parameters were estimated by the REML/BLUP method; and the simultaneous selection of productivity, stability, and adaptability of the genotypes was based on harmonic means of relative performances of predicted genotypic values (HMRPPGV). The Amélia, Angelina, and Tainá cultivars stood out for yield. The Regiane and Elisa cultivars presented significant responses in yield and number of leaves and are the most suitable for growing in the environmental conditions of Mossoró, RN, Brazil. The Crespa and Mimosa groups presented no stability and adaptability to the environmental conditions in which the experiments were conducted. More genotypes of all lettuce groups should be evaluated, and breeding programs should be developed to obtain genotypes with higher productivity, quality, and resistance to heat for semiarid regions. ADAPTABILIDADE E ESTABILIDADE FENOTÍPICA DE CULTIVARES DE ALFACE EM REGIÃO DE CLIMA SEMIÁRIDORESUMO -O estudo de genótipos, em diferentes ambientes ou épocas de cultivo, tem grande importância para a cultura da alface, cuja expressão do potencial produtivo é influenciada pelas condições ambientais. Deste modo, a aplicação da metodologia de modelos mistos (REML/BLUP) tem sido utilizada para avaliar os efeitos da interação genótipo x ambiente. Assim, o objetivo do presente trabalho foi estimar os parâmetros de adaptabilidade e estabilidade fenotípica que estão relacionados a produção de cultivares de alface em região de clima semiárido utilizando modelo misto. Avaliaram-se doze cultivares de alface dos grupos Americana (quatro repetições. Os parâmetros genéticos foram estimados pela metodologia REML/BLUP e a seleção simultânea da produtividade, estabilidade e adaptabilidade dos genótipos, baseou-se no método da média harmônica da performance relativa dos valores genotípicos preditos (MHPRVG). As cultivares Amélia, Angelina e Tainá sobressaíram-se para a produtividade. As cultivares Regiane e Elisa foram responsivas para o número de folhas e produtividade, sendo as mais indicadas para o cultivo nas condições de Mossoró. Os grupos Crespa e Mimosa não foram adaptados e estáveis nas condições ambientais em que foram conduzidos os ensaios. Recomenda-se que mais genótipos de todos os grupos de ...

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