Recently, researches have shown that the Brazilian savannah has a great potential to supply the demand for barley grains. The purpose of this study was to assess the genetic variability in 39 elite barley (Hordeum vulgare L.) genotypes based on the agro-morphological traits of a crop irrigated in the savannah system. An irrigation experiment in the design of complete randomized block with four replicates was conducted at Federal District - Brazil. The evaluated traits were: distance from the last knot to the rachis, distance from the flag leaf to rachis, spike length, number of grains by ear, flag leaf area, plant height, silking, lodging, grain yield, thousand-seed weight, protein content and grain commercial classification. After using analysis of variance the means were used to estimate the genetic dissimilarity among all genotypes pairs based on the Mahalanobis’ generalized distance. Cluster analysis using genetic distance matrix was performed having Unweighted Pair Group Method using Arithmetic Means method (UPGMA) as the criteria. Highly significant differences were found among the genotypes for all traits evaluated. The high coefficient of genetic variation indicates the possibility of having genetic gains for all traits. The traits that most contributed to the variability were the flag leaf area and silking, while the protein content and lodging were the traits that contributed the least. Based on the cluster analysis, at least three major groups of similarity were found. There was a clustering trend of two and six-rowed materials. The most divergent genotypes were PFC 2005123, Antártica-1, Nandi and FM 404.
Sunflower (Helianthus annuus L.) is an annual crop that stands out for its production of high quality oil and for an efficient selection, being necessary to estimate the components of genetic and phenotypic variance. This study aimed to estimate genetic parameters, phenotypic, genotypic and environmental correlations and genetic variability on sunflower in the Brazilian Savannah, evaluating the characters grain yield (YIELD), days to start flowering (DFL) based on flowering date in R5, chapter length (CL), weight of a thousand achenes (WTA), plant height (H) and oil content (OilC) of 16 sunflower genotypes. The experiment was conducted at Embrapa Cerrados, Planaltina, DF, situated at 15º 35’ 30”S latitude, 47º 42’ 30”W longitude and 1.007m above sea level, in soil classified as dystroferric Oxisol. The experimental design used was a complete randomized block with four replicates. The nature for the effects of genotypes and blocks was fixed. Except for the character chapter length, genetic variance was the main component of the phenotypic variance among the genotypes, indicating high genetic variability and experimental efficiency with proper environmental control. In absolute terms, the genetic correlations were superior to phenotypic and environmental. The high values reported for heritability and selective accuracy indicated efficiency of phenotypic selection. Results showed high genetic variability among genotypes, which may contribute to the genetic improvement of sunflower.
1 February 2017 in Pesquisa Agropecuária Brasileira
The objective of this work was to estimate the genetic, phenotypic, and environmental parameters of 113 barley accessions (Hordeum vulgare), previously selected based on high yield, in an irrigated production system in the Cerrado (Brazilian savanna), for use in breeding programs in Brazil. The experiment was conducted in 2013 at two sites in the Federal District, using a randomized complete block design with three replicates. The evaluated traits were: grain yield, kernel plumpness, thousand grain weight, plant height, lodging, and days to heading. Significant differences were observed between environment and accessions for all studied traits, as well as genotype x environment interaction. The MCU 3832 PI 402310, MCU 3484 PI 401962, CI 08053 Custer, MCU 3634 PI 402112, and MCU 3816 PI 402294 accessions stood out regarding grain yield and kernel plumpness. It is possible to obtain high selection gains with high heritability values. However, indirect selection is not recommended in the experimental conditions due to the low genotypic and phenotypic correlations obtained. It is also possible to select barley accessions with high yield and early heading date simultaneously, an important factor in the genotype selection process for future experiments. The accessions from Colombia are the most adapted to the Cerrado conditions.
1 January 2019 in Pesquisa Agropecuária Brasileira
The objective of this work was to quantify the genetic variability of 213 conilon coffee accessions of the Robusta Tropical cultivar, based on chemical characteristics related to the quality of green coffee beans, as well as to identify promising accessions for the breeding program of irrigated conilon coffee in the Brazilian Cerrado. The chemical characteristics evaluated were: protein and caffeine contents, total soluble solids and total lipids, ether extract, pH, and total titratable acidity. The data were subjected to the principal component analysis and cluster analysis based on the similarities observed within the first two principal components using the minimum variance method (Wards) and, as a measure of similarity, the Euclidean distance. The three main components explained 72.64% of the total variation of the data. All characteristics, except pH, were correlated with the first three components. It was possible to separate the genotypes in three clusters, according to the similarities observed in the behavior of the variables. The evaluated accessions present genetic variability regarding the assessed quality characteristics of green coffee beans, and CPAC 160 and CPAC 32 are the most promising for the breeding program of conilon coffee for cultivation under irrigation in the Cerrado.
1 January 2023 in Pesquisa Agropecuária Brasileira
The objective of this work was to present a methodological alternative for studies of the characterization and selection of corn (Zea mays) genotypes, through the joint analysis of variance of an augmented block design, using Scott-Knott’s test, and to present the hybrids selected from the adopted strategy, to show its efficiency. For the application of the methodology, a case study was used: the selection of superior corn hybrids for the Brazilian Cerrado. In four locations, 70 experimental hybrids were evaluated in an augmented block design without replicates, with three controls replicated once in each block. The analysis of experimental groups applied to the augmented block design, followed by genotype classifications by Scott-Knott’s multiple comparison test, is a viable alternative for studies with a low number of replicates and a large number of genotypes. Based on the tested methodology, the following experimental hybrids are selected for grain yield: HT007, HT008, HT018, HT004, HT024, HT005, and HT071.
1 July 2013 in Crop Breeding and Applied Biotechnology