Desempenho agronômico de genótipos de milho sob condições de restrição hídrica Agronomic performance of maize genotypes under conditions of water restriction

O objetivo, deste trabalho, foi avaliar o desempenho agronômico de genótipos de milho, no município de Dois Vizinhos, Paraná, Brasil, em condições de restrição hídrica. Foram avaliados 36 genótipos pertencentes ao ensaio Sul Super Precoce quanto aos caracteres relacionados com a produção de grãos. Os genótipos utilizados foram fornecidos pela Embrapa Milho e Sorgo e fazem parte dos Ensaios de competição de cultivares de milho do Brasil. O cultivo foi realizado em condições de sequeiro, sendo o fornecimento de água limitado à ocorrência de precipitações pluviométricas. O experimento foi realizado na área experimental da Universidade Tecnológica Federal do Paraná, no delineamento experimental látice simples. As condições climáticas ocorridas durante o experimento foram de deficiência hídrica severa, interferindo negativamente no rendimento de grãos, assim como na variabilidade de resposta dos genótipos avaliados; mesmo nessas condições foi possível classificar os materiais quanto à maioria dos caracteres avaliados, sendo ‘30P34’ o mais produtivo com 4,73 T ha-1.The aim of this study was to evaluate the agronomic performance of maize genotypes in the municipals of Dois Vizinhos, Paraná, Brazil, in conditions of water restriction. We evaluated 36 genotypes belonging to the Early Super South test regarding the characters related to grain production. The genotypes used were supplied by Embrapa Maize and Sorghum and are part of the competition trials of maize cultivars in Brazil. The culture was grown under rainfed conditions, with limited water supply to the occurrence of rainfall. The experiment was conducted at the experimental Universidade Tecnológica Federal do Paraná, the experimental design were simple lattice. The climatic conditions that occurred during the experiment were of severe drought, negatively affect the yield and variability of response of genotypes, even in these conditions it is possible to classify materials for most of the traits, being ‘30P34’ the most productive with 4.73 t ha-1

Genetic divergence among interspecific Paspalum hybrids based on seed production traits

ABSTRACT The use of genetic divergence as a basis for identifying superior individuals, with greater heterozygosity, is important in view of the difficulty when selecting of dissimilar genotypes exhibiting high average for interest traits. The aim of this study was to evaluate the genetic divergence and the expression of seed production traits in seventeen apomictic Paspalum plicatulum × Paspalum guenoarum hybrids and two male parents (P. guenoarum). A randomized block design was used, with genotypes individually arranged into ten blocks. The following traits were assessed: total number of tillers/plant (TT), reproductive tiller/plant (RT), number of racemes per inflorescence (NRI), reproductive tiller height (RTH), inflorescence rachis length (IRL), number of seeds/inflorescence (NSI), weight of a thousand seeds (WTS) and seed production (SP). Genetic divergence among the genotypes was estimated using the Tocher method and UPGMA clustering, based on the generalized Mahalanobis distance (D2 ii’). The Tocher and UPGMA optimization methods showed high concordance. The traits that most contributed to genetic divergence were RTH (23.59%), IRL (21.63%), WTS (16.67%) and SP (14.23%). The presence of genetic diversity made it possible to identify divergent genotypes and those with high means for the traits studied, allowing the selection of genotypes with significant breeding potential. Repeated cross-breeding of female superior plants with the genotypes Azulão and H20 can result in a high heterosis effect on seed production characteristics

Genetic parameters and predicted gains with selection of interspecific hybrids of Paspalum for seed production

<div><p>Abstract The aim of this study was to estimate the genetic parameters and predicted gains with selection of interspecific hybrids of Paspalum in relation to seed production traits Data were analyzed in randomized block design, with 23 genotypes arranged into ten blocks, according to the methodology of mixed models by the REML/BLUP procedure. The traits considered in the study were: number of total tillers/plant, number of reproductive tillers/plant, number of racemes/inflorescence, number of seeds/inflorescence, weight of a thousand seeds and seed production. Variability among genotypes, high heritability (>0.50), except total tillers (0.44) and number of racemes (0.36), and high accuracy (>0.90) were identified for all traits. The hybrids 10E5052, 10E4026, 10E507, 10E4025 and 10E40104 are among the top ten because they have high genetic values in three or more traits, indicating that these genotypes should be recommended for direct use in planting or potential parents to be used in new crosses.</p></div