Ana Paula Oliveira Nogueira

Genetic diversity in soybean genotypes with resistance to Heterodera glycines.

The purpose of this study was to analyze the genetic diversity among soybean genotypes inoculated with Heterodera glycines race 3. The experiments were conducted in a greenhouse. In two performance tests of morphological characteristics and resistance to the pathogen, 27 soybean genotypes were assessed. The coefficient of genotypic determination was estimated by the method of analysis of variance and the genetic diversity analyzed based on dendrograms and optimization method. The estimated coefficients of determination indicated a predominantly genetic origin of the genotypic differences in the traits. The genetic variability was maintained in the superior genotypes, which can be used in breeding programs for resistance to soybean cyst nematode.

Industrial tomato lines: morphological properties and productivity

The tomato is the second most produced vegetable in the world, with significant participation in the human diet. In addition, the production of tomatoes generates jobs and family income. The availability of improved cultivars that provide greater profitability to the producer and satisfactorily meets the needs of the fresh fruit market and the processing industry becomes imperative due to its importance. Therefore, this study aimed to characterize and select industrial tomato lines in regard to fruit yield, number of leaf branches, and number of flower racemes (NFR). The experiment was conducted in 2014 in the experimental area of the Federal University of Goiás (Universidade Federal de Goiás). The design was a randomized block design with four replicates and 25 genotypes. The number of leaf branches (NB), NFR, and fruit productivity were evaluated. The results were analyzed using analysis of variance and the means compared by the Tukey test. A difference was observed (P ≤ 0.01) for all traits analyzed. The NB and NFR were related, where more branches promoted an increase in NFR and thus the productivity increases. In addition, a greater number of fruits implied in smaller fruit size, and consequently lower fruit mass. The lowest number of fruit per plant caused increased fruit size and mass. The lines CVR 1, CVR 3, CVR 4, CVR 5, CVR 21, and CVR 22 were suitable for genetic enhancement of tomato and provided the greatest productivity.

Phenotypic and genotypic correlations between soybean agronomic traits and path analysis

The goals of this research were to evaluate the phenotypic and genotypic correlations between agronomic traits, to perform path analysis, having as main character grain yield, and to identify indirect selection criteria for grain yield. The experiment was carried out in an experimental area located at Capim Branco farm, which belongs to Federal University of Uberlândia, during the growing season of 2015/2016.Twenty-four soybean genotypes were evaluated under randomized complete block design with three repetitions, of which agronomic traits and grain yield were measured. There was genetic variability for all traits at 5% probability level through the F-test. Thirty significant phenotypic correlations were also observed with values oscillating from 0.42 to 0.87, which indicated a high level of association between some evaluated traits. Additionally, we verified that phenotypic and genotypic correlations were essential of the same direction, being the genotypic ones of superior magnitudes. Plants with superior vegetative cycle had longer life cycles; this fact could be explained by the significant phenotypic correlations between the number of days to the blooming and number of days to maturity (0.76). Significantly positive phenotypic and genotypic correlations for the total number of pods per plant and grain yield per plant (0.84) were observed. Through the path analysis, the trait that contributed the most over grain yield was the number of pods with three seeds as it showed the highest direct effect on grain yield per plant, as well as a strong indirect effect on the total number of pods. Therefore, the phenotypic and genotypic correlations suggested high correlations between grain yield and number of branched nodes, the number of pods with two and three seeds, and the total number of pods. Also, the path analysis determined the number of pods with three seeds as having the highest favorable effect on grain yield, and thus, being useful for indirect selection toward productive soybean genotypes.

Genetic parameters and selection of soybean lines based on selection indexes

Defining selection criteria is important to obtain promising genotypes in a breeding program. The objective of this study was to estimate genetic parameters for agronomic traits and to perform soybean line selection using selection indices. The experiment was conducted at an experimental area located at Capim Branco farm, belonging to the Federal University of Uberlândia. A total of 37 soybean genotypes were evaluated in randomized complete block design with three replicates, in which twelve agronomic traits were evaluated. Analysis of variance, the Scott-Knott test at the 1 and 5% level of probability, and selection index analyses were performed. There was genetic variability for all agronomic traits, with medium to high levels of genotype determination coefficient. Twelve lines with a total cycle up to 110 days were observed and grouped with the cultivars MSOY 6101 and UFUS 7910. Three lines, UFUS FG 03, UFUS FG 20, and UFUS FG 31, were highlighted regarding grain yield with higher values than the national average of 3072 kg/ha. The direct selection enabled the highest trait individual gains. The Williams (1962) index and the Smith (1936) and Hazel (1943) index presented the highest selection gain for the grain yield character. The genotype-ideotype distance index and the index of the sum of ranks of Mulamba and Mock (1978) presented higher values of total selection gain. The lines UFUS FG 12, UFUS FG 14, UFUS FG 18, UFUS FG 25, and UFUS FG 31 were distinguished as superior genotypes by direct selection methods and selection indexes.

Correlations between traits in soybean (Glycine max L.) naturally infected with Asian rust (Phakopsora pachyrhizi)

Soybean (Glycine max L.)-breeding programs aim to develop cultivars with high grain yields and high tolerance to Asian soybean rust (Phakopsora pachyrhizi). Considering that the traits targeted for breeding are mainly quantitative in nature, knowledge of associations between traits allows the breeder to formulate indirect selection strategies. In this study, we investigated phenotypic, genotypic, and environmental correlations between the agronomic traits of soybean plants naturally infected with P. pachyrhizi, and identified agronomic traits that would be useful in indirectly selecting soybean genotypes for high yields. The study was conducted on the Capim Branco Farm, Uberlândia, Brazil, with 15 soybean genotypes, which were cultivated in a completely randomized block design with four replications. Fourteen phenotypic traits were evaluated using the GENES software. The phenotypic and genotypic correlations were positive and of a high magnitude between the total number of pods and the number of pods with two or three grains, indicating that the total number of pods is a useful trait for the indirect selection of soybean genotypes for high grain yields. Strong environmental correlations were found between plant height at blooming and maturity and grain yield and yield components.

Analysis of the genetic divergence of soybean lines through hierarchical and Tocher optimization methods

This study aimed to evaluate the clustering pattern consistency of soybean (Glycine max) lines, using seven different clustering methods. Our aim was to evaluate the best method for the identification of promising genotypes to obtain segregating populations. We used 51 generations F5 and F6 soybean lines originating from different hybridizations and backcrosses obtained from the soybean breeding program of Universidade Federal de Uberlândia in addition to three controls (Emgopa 302, BRSGO Luziânia, and MG/BR46 Conquista). We evaluated the following agronomic traits: number of days to flowering, number of days to maturity, height of the plant at maturity, insertion height of the first pod, grain yield, and weight of 100 seeds. The data was submitted to analyses of variance followed by average Euclidean distance matrix estimation used as measure of dissimilarity. Subsequently, clusters were formed using the Tocher method and dendrograms were constructed using the hierarchical methods simple connection (nearest neighbor), complete connection (most distant neighbor), Ward, median, average within cluster connection. The nearest neighbor method presented the largest number of genotypes in group I and showed the greatest similarity with the Tocher optimization method. The joint use of these two methodologies allows for differentiation of the most genetically distant genotypes that may constitute the optimal parents in a breeding program.

Selection for wide adaptability and high phenotypic stability of Brazilian soybean genotypes

Advances in genetic enhancement techniques have led to an increase in soybean production. Thus, soybean is currently one the most economically important cultured species worldwide. The objectives of the present study were to study the interaction of soybean genotypes per environment in terms of grain productivity and to evaluate their phenotypic adaptability and stability, with the final aim of selecting lineages with high productivity, wide adaptability, and high stability. Seven soybean genotypes, consisting of five lineages developed by the soybean genetic enhancement program of the Universidade Federal de Uberlândia (Brazil) and two controls, were evaluated during several annual cycles in seven different environments. A randomized complete block design (RCBD) with three replicates was adopted in each site. This study followed the methodology proposed by Eberhart and Russel and Lin and Binns, with modifications by Carneiro, and the AMMI (additive main effects and multiplicative interaction model) analysis. The average productivity of soybean cultivars in the trials was 2739.26 kg/ha. The L01V13 genotype and the UFUS Guarani cultivar had wide adaptation according to the methodology proposed by Eberhart and Russel and Lin and Binns, with modifications by Carneiro. When analyzed with the AMMI model, the UFUS Guarani cultivar showed high stability. In general, the methodologies studied are complementary and, when used together, increase the reliability of the classification, providing support for the use of specific soybean cultivars in different environments.

Genetic divergence in soybeans based on phenotypic traits and microsatellite markers

Background The success of a breeding program depends on the existence of genetic variability [1]. Therefore, breeders have recommended to the formation of the population-based study, the interbreeding between superior cultivars and divergent, resulting in hybrid combinations of higher heterotic effect, so that in segregating generations it has a greater chance of obtaining transgressive genotypes [2]. Microsatellite markers or Simple Sequence Repeat (SSR) have been widely used to estimate genetic diversity in soybean due to their high degree of polymorphism, codominant inheritance, PCR-based detection, allelic diversity and the knowledge of the location of the marker in the genome the species [3]. In this report we present results of agronomic traits and microsatellite markers to evaluate the genetic diversity of 35 soybean genotypes to determine their potential as parents for breeding programs.

BAP effect in vitro germination of soybean cultivars UFUS Xavante an UFUS Carajás

Background Plant tissue culture is a biotechnology particularly relevant to plant genetic transformation. The ability of in vitro regeneration is one of the requirements for the production of usable plants in breeding programs [1]. As each genotype has a specific regeneration potential, several protocols have been developed with the aim of developing methodologies that can speed up the germination process [2]. In vitro, culture media for plants, not only provide macro and micronutrients, but also carbohydrates, usually sucrose as a carbon source. Better results are obtained by adding organic compounds such as vitamins, amino acids and growth regulators [3].