Evaluation of the stability and adaptability of genotypes across different environment conditions is important for release and recommendation of new varieties to ensure their high adaptability. Plant breeders evaluate germplasms in multi-environment trials to study the stability and adaptability of genotypes (G) and to recommend the genotypes to different environments (E). Multienvironment trials for 11 genotypes including 4 check varieties of cotton were carried out during 3 seasons in 3 locations in Mozambique. The objective of this study was to assess the G x E pattern and to evaluate the stability and adaptability of seed cotton yield of a new germplasm in Mozambique. The experiment was set up in Namialo (district of Meconta province of Nampula), Namara (district of Balama, province of Cabo Delgado) and Nhamatanda (district of Nhamatanda province of Sofala). The treatments consisted of 11 varieties, which were established in a randomized complete block design with four replications. The graphic analysis of additive main effect and multiplicative interaction (AMMI) were used to understand the G x E interaction pattern and to study the stability and adaptability. The results showed significant effect of genotype, environment and G x E interaction. The first two principal components explained about 80% of the detected interaction. The pair of Environment/Genotype showed the E/G combination for high performance. The genotypes and environments showed genetic and environmental performance dissimilarity. The AMMI revealed that genotypes FK 37, BA 919 and Flash were the most adaptable, while BA 2018 and BA 320 were the most stable across the variation of environments. Keywords: AMMI, Biplot, GGE, genotype x environment interaction, seed cotton yield. Abbreviations:AMMI_Additive main effect and multiplicative interaction; GE_Genotype by Environment interaction; GGE_ Genotype main effect plus genotype by environment interaction; GOT_Ginning out-turn; PCA_Principal component analysis.

In the process of introducing cotton cultivars, it is essential to assess their productive behavior for different environments for which they will be recommended. Knowledge of the magnitude of the genotype interaction with environment allows the evaluation of the stability and adaptability of genotypes where one intends to introduce them, in addition to enabling the evaluation of the production potential and possible limitations of each environment. The study was conducted to determine the productivity, genotypic adaptability and genotypic stability of nine cotton cultivars (Gossypium hirsutum) in Mozambique, from 2004 to 2010 growing seasons. The genotypic stability and genotypic adaptability were assessed by Residual Maximum Likelihood (REML) and predict breeding values using Best Linear Unbiased Prediction (BLUP) methodology. The cultivars ISA 205, STAM 42 and REMU 40 showed superior productivity when they were selected by the Harmonic Mean of Genotypic Values (HMGV) criterion in relation to others. In turn, the cultivars CA 222, STAM 42 and ISA-205 were superior when selected by the Relative Performance of Genotypic Values (RPGV) and Harmonic Mean of the Relative Performance of Genotypic Values (HMRPGV). The cultivars CA 324 had the lower values for all criterions above. The cultivars CA 222 and STAM 42 will be the most recommended for farmers in cotton-growing regions and for the Cotton Breeding Program of Mozambique.

The genetic diversity of species is an important way to maintain the natural capacity to respond to climate change and all stresses. This study aimed to estimate the general combining ability (GCA) and the specific combining ability (SCA) of the characteristics among 41 cotton cultivars and 9 inbred lines using circulant diallel. In 2016, 41 cultivars and 9 inbred lines and 75 hybrid combinations were evaluated at the Namialo Cotton Research and Seed and Multiplication Centre in the Meconta District, Nampula province. The experimental design was Federer's augmented blocks with four repetitions. The evaluated characteristics were: days for 50% of flowering (DAFlw), days for 50% of fruiting (DAFrut), plant height, average number of bolls (AnB), seed cotton yield in kilograms per hectare (Yield) and the mass of one hundred seeds (M100). The algorithm for establishing diallel crosses was based on Kempthorne and Curnow, where S was equal to 3. There was a predominance of non-additive effects for all characteristics analysed. The genotypes ALBAR FQ 902, IRMA 12-43 and MARICO showed greater additive effects for DAFlw, DAFrut, AnB, Yield and, M100