Estabilidade e adaptabilidade fenotípica dos caracteres agronômicos e de fibras em linhagens de algodoeiro herbáceo na região semiárida do nordeste

Abstract

The herbaceous cotton (Gossypium hirsutum L.) is one of the main species cultivated for fiber production, being exploited in tropical and subtropical regions. Brazil stands out on the world stage as one of the main cotton fiber producers and exporters. In developing breeding programs, it is important that the crop is subjected to adverse conditions, such as annual variations in rainfall, temperature and humidity. Thus, the study of the genotype x environment (GxA) interaction can be carried out through tests of stability and phenotypic adaptability, which will help in choosing the best plant materials for a given region. The present work aimed to characterize and evaluate the magnitude of the GxA interaction on the production and fiber quality characters of the genotypes of the final lines of herbaceous cotton for the Brazilian semiarid region. Seventeen genotypes were evaluated in experiments conducted in the cities of Apodi-RN and Barbalha-CE in the years 2016 and 2017, totaling four environments. The characteristics evaluated were: boll weight, seed cotton yield, fiber yield, fiber percentage, length, strength, micronaire and reliability. Individual and joint analysis of variance and analysis of adaptability and stability were performed following the methodologies proposed by Eberhart and Russell (1966), Lin and Binns (1988) modified by Carneiro (1998), Annicchiarico (1992) and Wricke (1965). The different methodologies adopted in this study were consistent and complementary, being efficient and easy to apply in the identification of adapted and stable cotton genotypes. The results obtained indicated that the genotypes CNPA BA 2011-751, CNPA GO 2010-147, CNPA GO 2009 195 and FM 993, with high productivity, wide adaptability and stability to the cultivation conditions in the semi-arid region of the Northeastern Brazil.