Time filter

Source Type

Panambi, Brazil

Nascimento M.,Federal University of Vicosa | Finoto E.L.,Polo Regional Centro Norte | Sediyama T.,Federal University of Vicosa | Cruz C.D.,Federal University of Vicosa
Crop Breeding and Applied Biotechnology | Year: 2010

The objective of this study was to evaluate the influence of genotype x environment interaction on the seed oil and protein content in soybean genotypes (Glycine max L. Merrill). Fifteen soybean genotypes were evaluated. The experiments were conducted in the growing seasons 2004/05, 2005/06 and 2006/07 in Viçosa and Frutal, Minas Gerais (MG), and Pindorama, São Paulo (SP), respectively, with different planting dates and soil types, in a total of 13 environments. The evaluation was based on the methods of Eberhart and Russell and Extended Centroid. The results showed that genotype UFV 18 is desirable in soybean breeding programs designed to increase the values of the two traits evaluated. The results of genotype PTN-Bio were different for each trait. Moreover, it was noted that the Extended Centroid method is more conservative than the methodology of Eberhart and Russell in the classification of genotypes.

Favero A.P.,Embrapa Pecuaria Sudeste | Padua J.G.,Embrapa Recursos Geneticos e Biotecnologia | Costa T.S.,Embrapa Recursos Geneticos e Biotecnologia | Gimenes M.A.,Embrapa Recursos Geneticos e Biotecnologia | And 3 more authors.
Genetics and Molecular Research | Year: 2015

The primary gene pool of the cultivated peanut (Arachis hypogaea L., allotetraploid AABB) is very narrow for some important characteristics, such as resistance to pests and diseases. However, the Arachis wild diploid species, particularly those from the section Arachis, still have these characteristics. To improve peanut crops, genes from the wild species can be introgressed by backcrossing the hybrids with A. hypogaea. When diploid species whose genomes are similar to those of the cultivated peanut are crossed, sterile hybrids result. Artificially doubling the number of chromosomes of these hybrids results in fertile synthetic polyploids. The objectives of this study were: 1) to obtain progenies by crossing amphidiploids with the cultivated peanut, and 2) to characterize these two groups of materials (amphidiploids and progenies) so that they may be efficiently conserved and used. Using morphological, molecular, and pollen viability descriptors we evaluated one cultivar of A. hypogaea (IAC 503), eight synthetic amphidiploids, and the progenies resulting from four distinct combinations of crossing between IAC 503 and four amphidiploids. © FUNPEC-RP.

Filho J.A.A.,APTA | Martins A.L.M.,Polo Regional Centro Norte
Scientia Agricola | Year: 2011

Lippia alba (Mill.) N.E.Br. is an aromatic and medicinal shrub native to the American continent. Despite its potential as a source of essential oil for the pharmaceutical and cosmetics industries, few selection and genetic improvement studies have been carried out. The aim of this study was to provide genetic information on this species for breeding programs, showing its selection potential, by investigating clonal half-sib progenies. The following characteristics were evaluated per plant: leaf dry mass (LDM), total dry mass (TDM), leaf yield (LY), essential oil yield (EOY) and oil production (OP). Estimates were made for the several genetic parameters including absolute genetic gain at 30% selection intensity, correlations and relative contribution of additive and environmental effects to phenotypic correlation. Two experimental trials on 30 progenies were conducted: one in Campinas, state of São Paulo (SP), Brazil, with two harvests of the aerial part, and one in Monte Alegre do Sul, SP, Brazil, with only one harvest. The trials were conducted in a randomized block design consisting of subplots with three replications, each plot (progeny) consisting of 8 to 15 clonally-replicated plants with subplot harvesting. Variations were detected between progenies and harvests, as well as progeny/harvest interactions in the split plot experiment. High heritability and genetic gains were obtained at both sites for LDM, TDM and OP. The lowest variations among progenies were obtained for LY and EOY, highlighting selection problems. Negative additive genetic correlations were obtained for EOY × LDM, EOY × TDM, LY × TDM and LY × LDM. Selection for LDM resulted in increased oil production per plant (OP), even where there was a negative correlation between LDM × EOY.

Resistance to late leafspot (Cercosporidium personatum) and agronomic condition of peanut plants were assessed in segregating RC1F2 populations obtained from crosses between the amphidiploid (A. ipaensis x A. duranensis) and the recurrent parent, cultivar Runner IAC 886. The experiment was carried out at Pindorama, SP, under natural field conditions of the disease. Disease was evaluated at two dates during the growing cycle, in 1,500 plants, using a scale of visual notes ranging from 1 to 9, and taking into consideration the number of lesions in leaves and the degree of defoliation caused by the disease. The data obtained were used to estimate the AUDPC (Area Under the Disease Progress Curve). Agronomic evaluations were performed after harvesting, in 90 randomly taken plants. The following agronomic characters were evaluated: Pod and kernel production per plant, shelling percentage, number of pods per plant, number and percentage of two-seed pods. The results showed wide variability for resistance to the disease. Depending on the hypogaea parent used in the initial crosses with the amphidiploids, 4,2 to 7,7% of plants with disease resistance close to the wild resistant parent (A. ipaensis) could be rescued in the F2 generation. Significant differences were observed between RC1F2 plants descendent from the same F1 plant, in either disease resistance or in agronomic traits, due to the segregant condition of the F4 plants used in the crosses to the recurrent parent, cultivar Runner IAC 886. Some of the RC1F1:2 plant families exhibited agronomic condition close to the cultivar IAC Caiapó, especially in production of pods and kernels, shelling percentage and average kernel weight. However, the large majority of the segregants in this generation still showed high percentages of one-seed pods. This condition, and the negative correlations observed between resistance to the disease and agronomic traits such as pod and kernel production per plant and average kernel weight suggest that a new backcrossing cycle is needed to break eventual undesirable linkages and generate resistant individuals closer to the commercial standards.

Crosariol Netto J.,Sao Paulo State University | Michelotto M.D.,Polo Regional Centro Norte | Grigolli J.F.J.,Fundacao MS | Galli J.A.,Polo Regional Centro Norte | And 2 more authors.
Bioscience Journal | Year: 2015

This study evaluated the symptoms of attack by the green belly stink bug, Dichelops melacanthus (Dallas, 1851), in conventional and transgenic commercial corn (Zea mays) hybrids, the seeds of which were either treated using the insecticide thiamethoxam or without chemical treatment. The experiment was conducted during the 2010/2011 crop season in Pindorama, São Paulo State, Brazil. The percentage of plants with symptoms or injuries was recorded by visually evaluating the degree or intensity of attack symptoms. The height of the plants was also recorded on a weekly basis, until the plants were 40 DAE. We also measured yield compounds, such as the number of rows of grain/spikes, spike weight (with and without straw), and grain weight. The seeds of hybrids that had previously been treated with thiamethoxam showed lower percentage of the number of plants that were attacked. Further, the grain weight of the plants increased 29.5% more than that of plants from untreated seeds. It was also found that transgenic hybrids exhibited lower height reduction in 40 DAE plants than did conventional isolines. Visual inspection is effective in assessing the degree of injury caused by attacks to the developing plants. © 2015, Biosci. J., All rights Reserved.

Discover hidden collaborations