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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11845
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Item Genetic parameters and variability in physic nut accessions during early developmental stages(Pesquisa Agropecuária Brasileira, 2010-10) Laviola, Bruno Galvêas; Rosado, Tatiana Barbosa; Bhering, Leonardo Lopes; Kobayashi, Adilson Kenji; Resende, Marcos Deon Vilela deThe objective of this work was to estimate the genetic parameters and variability among accessions (half-sib families) of physic nut (Jatropha curcas) during the early stages of development. For this study, 110 accessions in the first year of development of the physic nut germplasm bank, maintained at Embrapa Cerrados, DF, Brazil, were evaluated in situ. The experiment was established in a randomized complete block design, with two replicates and five plants per plot arranged in rows at 4x2 m spacing. Grain yield, total number of branches per plant, plant height, stem diameter, canopy projection on the row, canopy projection between rows, canopy volume, number of days until first flowering and height of the first inflorescence were evaluated. Estimates of vegetative genetic parameters showed the existence of genetic variability in the physic nut germplasm bank. Physic nut accessions of the germplasm bank were grouped into five similarity groups based on character divergence. Although preliminary, the obtained results are promising for showing potential for Jatropha improvement with selective efficiency.Item Evaluation of grain sorghum hybrids for aluminum tolerance in nutrient solution(Acta Scientiarum. Agronomy, 2018) Menezes, Cicero Beserra de; Lima, Geisiane Matos; Marucci, Rosangela Cristina; Bernardino, Karine Costa; Santos, Crislene Vieira dos; Júlio, Marcos Paulo Mingote; Schaffert, Robert EugeneSorghum (Sorghum bicolor L. Moench) is one of the most important cereal crops in the world. In Brazil, the acreage of grain sorghum during off-season is quite expansive. Most of this area is the Cerrado, a Brazilian biome that is similar to a Savannah and is characterized by high acidity and soluble aluminum at toxic levels for plants. The aluminum acts as a limiting factor in achieving high yields. The purpose of this work was to phenotype sorghum hybrids for aluminum tolerance. Eighteen hybrids were evaluated in a nutrient solution containing {0} or {27} µM Al3+. The work was carried out in a growth chamber at the Embrapa Maize and Sorghum, from April 4 to May 30, 2014. The lines ATF 13B (susceptible) and ATF 14B (tolerant) were used as check cultivars. Based on the Net Root Growth after 120 hours (NRG120), Net Root Growth (NRG168) after 168 hours and Relative Net Root Growth after 168 hours (RNRG168), it was possible to distinguish tolerant hybrids from susceptible ones. The high aluminum saturation reduced root growth by 70%. The hybrids BRS 310 and BRS 373 were tolerant to aluminum stress under nutrient solution. The hybrid BRS 330 was clustered in an intermediate group, with an approximately 50% root growth reduction. The other hybrids were susceptible with significant root reduction.Item Early selection enabled by the implementation of genomic selection in Coffea arabica breeding(Frontiers in Plant Science, 2019-01) Sousa, Tiago Vieira; Caixeta, Eveline Teixeira; Alkimim, Emilly Ruas; Oliveira, Antonio Carlos Baião; Pereira, Antonio Alves; Sakiyama, Ney Sussumu; Zambolim, Laércio; Resende, Marcos Deon VilelaGenomic Selection (GS) has allowed the maximization of genetic gains per unit time in several annual and perennial plant species. However, no GS studies have addressed Coffea arabica, the most economically important species of the genus Coffea. Therefore, this study aimed (i) to evaluate the applicability and accuracy of GS in the prediction of the genomic estimated breeding value (GEBV); (ii) to estimate the genetic parameters; and (iii) to evaluate the time reduction of the selection cycle by GS in Arabica coffee breeding. A total of 195 Arabica coffee individuals, belonging to 13 families in generation of F2 , susceptible backcross and resistant backcross, were phenotyped for 18 agronomic traits, and genotyped with 21,211 SNP molecular markers. Phenotypic data, measured in 2014, 2015, and 2016, were analyzed by mixed models. GS analyses were performed by the G-BLUP method, using the RKHS (Reproducing Kernel Hilbert Spaces) procedure, with a Bayesian algorithm. Heritabilities and selective accuracies were estimated, revealing moderate to high magnitude for most of the traits evaluated. Results of GS analyses showed the possibility of reducing the cycle time by 50%, maximizing selection gains per unit time. The effect of marker density on GS analyses was evaluated. Genomic selection proved to be promising for C. arabica breeding. The agronomic traits presented high complexity for they are controlled by several QTL and showed low genomic heritabilities, evidencing the need to incorporate genomic selection methodologies to the breeding programs of this species.Item The difference between breeding for nutrient use efficiency and for nutrient stress tolerance(Crop Breeding and Applied Biotechnology, 2011-09) Maia, Ciro; Vale, Júlio César Do; Fritsche- Neto, Roberto; Cavatte, Paulo Cezar; Miranda, Glauco VieiraThis study aimed to verify the relationship between breeding for tolerance to low levels of soil nutrients and for nutrient use efficiency in tropical maize. Fifteen inbred lines were evaluated in two greenhouse experiments under contrasting levels of N and P. The relationship between nutritional efficiency and tolerance to nutritional stress was estimated by the Spearman ranking correlation between the genotypes for the traits related to N and P use efficiency and phenotypic plasticity indices. The lack of relationship between the traits, in magnitude as well as significance, indicates that these characters are controlled by different gene groups. Consequently, simultaneous selection for both nutrient use efficiency and tolerance to nutritional stress is possible, if the mechanisms that confer efficiency and tolerance are not competitive.Item DNA marker-assisted selection to pyramid rust resistance genes in “carioca” seeded common bean lines(Euphytica, 2014-05-07) Carneiro, José Eustáquio S.; Moreira, Maurilio A.; Barros, Everaldo G.; Souza, Thiago Lívio P. O.; Ragagnin, Vilmar A.; Dessaune, Suelen N.; Sanglard, Demerson A.This work reports a gene pyramiding approach assisted by DNA markers used to develop “carioca” seeded common bean (Phaseolus vulgaris L.) elite lines harboring three different rust resistance genes. Rust is among the most destructive diseases that attack P. vulgaris and cause serious damage worldwide. The rust resistance genes Ur-5 (from ‘Mexico 309’), Ur-11 (from ‘BelMiDak RR-3’), and Ur-14 (from ‘BRS Pioneiro’, a “carioca” seeded cultivar derived from the resistance source ‘Ouro Negro’) were combined in the “carioca” seeded bean cultivar ‘Rudá’. Firstly, two different backcross programs were conducted separately to produce progenies harboring individually the Ur-5 and Ur-11 genes. Molecular fingerprinting analysis was used to select plants genetically similar to ‘Rudá’ in the backcross cycles to accelerate the recurrent-background recovery. The obtained progenies were initially intercrossed and then crossed with ‘BRSMG Pioneiro’ (Ur-14). The final F1 plants derived from these crosses were screened with DNA markers linked to the three rust resistance genes: SI19 (Ur-5), SAE19 (Ur-11) and OPX11 (Ur-14). The plants selected as harboring all the alleles of interest were used to obtain the next generations. The selection based on DNA markers was conducted up to the F4:5 generation. We were able to select F4:7 progenies showing all the DNA markers associated to the genes of interest and resistant to all specific races of U. appendiculatus used for phenotypically detecting each one of the rust resistance genes. Yield evaluations show that these selected lines are as productive as the recurrent parent ‘Rudá’ and high-performing control cultivars grown in Brazil.Item Establishment of new strategies to quantify and increase the variability in the Brazilian Jatropha genotypes(Industrial Crops and Products, 2018-07) Bhering, Leonardo Lopes; Laviola, Bruno Galveas; Alves, Alexandre Alonso; Formighieri, Eduardo Fernandes; Peixoto, Leonardo de AzevedoThe genetic diversity of Brazilian Jatropha (Jatropha curcas) germplasm collection (BJGC), which consists of 192 accessions, has been previously reported based on the evaluation of a limited number of RAPD and SSR markers. In addition, accessions from other countries (Guatemala and Mexico) were introduced to this collection without prior information on their relation with the existing collection. Thus the objective of this study were to develop and validate a panel for high-density genome-wide molecular markers for Jatropha; to compare the diversity of the germplasm collected in Brazil and the materials introduced and/or generated by crossing selected genotypes; and to determine whether the germplasm introduction strategies and the controlled crossings were efficient in generating/increasing the genetic variability available to the breeding program. This study reported an evaluation on the existence and on the structure of the genetic diversity of a core collection of 92 accessions by using DArT and SNP markers. The genotyping-by-sequencing approach allowed genotyping 747 polymorphic SNP and 4007 DArTs. The pairwise genetic dissimilarity was estimated according to the Jaccard’s coefficient, and clustered by the UPGMA and Tocher’s clustering methods The genetic diversity distribution was assessed by the analysis of molecular variance (AMOVA). The mean dissimilarity between accessions was low (0.165), and it confirmed that the diversity of the BJGC is very limited. Cluster analysis demonstrated that the introduced genotypes were divergent, and they formed a separate group, indicating that new introductions such as these will be important to promote future efforts on genetic breeding. Accordingly, data from SNP also confirmed the development of a significant amount of genetic variability within families (65%), which probably resulted from the use of the Mexican accession that was found to be considerably divergent when compared with the Brazilian accessions. These results indicate that breeders should focus on two main strategies to generate variability in the BJGC: introduction of new accessions from other countries and crossings between potential genotypes.Item The polyploidy and its key role in plant breeding(Planta, 2015-12-29) Sattler, Mariana Cansian; Carvalho, Carlos Roberto; Clarindo, Wellington RonildoPolyploidy is a major force in the evolution of both wild and cultivated plants. Polyploid organisms often exhibit increased vigor and, in some cases, outperform their diploid relatives in several aspects. This remarkable superiority of polyploids has been the target of many plant breeders in the last century, who have induced polyploidy and/or used natural polyploids in many ways to obtain increasingly improved plant cultivars. Some of the most important consequences of polyploidy for plant breeding are the increment in plant organs (“gigas” effect), buffering of deleterious mutations, increased heterozygosity, and heterosis (hybrid vigor). Regarding such features as tools, cultivars have been generated with higher yield levels, improving the product quality and increasing the tolerance to both biotic and abiotic stresses. In some cases, when the crossing between two species is not possible because of differences in ploidy level, polyploids can be used as a bridge for gene transferring between them. In addition, polyploidy often results in reduced fertility due to meiotic errors, allowing the production of seedless varieties. On the other hand, the genome doubling in a newly formed sterile hybrid allows the restoration of its fertility. Based on these aspects, the present review initially concerns the origin, frequency and classification of the polyploids, progressing to show the revolution promoted by the discovery of natural polyploids and polyploidization induction in the breeding program status of distinct crops.Item Parental selection in diallel crosses of Jatropha curcas using mixed models(Acta Scientiarum. Agronomy, 2017-04-12) Teodoro, Paulo Eduardo; Laviola, Bruno Galvêas; Peixoto, Leonardo Azevedo; Bhering, Leonardo LopesDiallel crosses in an unbalanced scheme were carried out in Jatropha to (i) evaluate the additive and non-additive genetic components; (ii) select parents through the general combining ability; (iii) estimate the specific combining ability used in the crosses; and (iv) verify the existence of the maternal effect and inbreeding depression. The experiment was carried out in a complete diallel scheme with four progenitors, unbalanced for the number of crosses. The experimental design consisted of a randomized block, with 5 replications and 3 plants per plot. The following characteristics were evaluated: stem diameter (SD), number of branches (NB), plant height (PH), canopy projection on the row (CPR), canopy projection between rows (CPB), mass of hundred grains (MHG) and grain yield (GY). Estimates of variances were obtained using the method of restricted maximum likelihood, while breeding values were estimated by the best linear unbiased prediction. It was concluded that the additive effect was predominant in the genetic control for SD, CPR, and CPB; the dominance effect was predominant for PH, NB, and GY; there was a cytoplasmic effect and nuclear genes of the female parent for all evaluated traits; parents 107 and 190 are promising for reducing the size and increasing the grain yield; there was inbreeding depression for SD and GY; and the favorable crosses for increasing GY were 190x107 and 190x190.Item Application of neural networks to predict volume in eucalyptus(Crop Breeding and Applied Biotechnology, 2015-03-16) Bhering, Leonardo Lopes; Cruz, Cosme Damião; Peixoto, Leonardo de Azevedo; Rosado, Antônio Marcos; Nascimento, Moysés; Laviola, Bruno GalveasThe aim of this study was to evaluate the methodology of Artificial Neural Networks (ANN) in order to predict wood volume in eucalyptus and its impacts on the selection of superior families, and to compare artificial neural network with regression models. Data used were obtained in a random block design with 140 half-sib families with five replications at three years of age, and four replications at six years of age, both with five plants per plot. The volume was estimated using ANN and regression models. It was used 2000 and 1500 data to train ANN, and 1500 and 1300 to validate ANN for 3 and 6 years of age, respectively. It is concluded that ANN can help improving the accuracy to measure the volume in eucalyptus trees, and to automate the process of forestry inventory and were more accurate in predicting wood volume than almost all regression models.Item Selection of strawberry cultivars with tolerance to Tetranychus urticae (Acari: Tetranychidae) and high yield under different managements.(Genetics and Molecular Research, 2017-04-28) Costa, A.F.; Teodoro, P.E.; Bhering, L.L.; Fornazier, M.J.; Andrade, J.S.; Martins, D.S.; Zanuncio Junior, J.S.Tetranychus urticae Koch (Acari: Tetranychidae) is considered the main pest of strawberry. Several factors can favor its development, among them the genotype susceptibility and cropping system. The aims of this study were to evaluate the agronomic performance of strawberry cultivars under different managements and to identify strawberry cultivars that meet tolerance to T. urticae and high fruit yield. Thirteen cultivars of strawberry ('Albion', 'Aleluia', 'Aromas', 'Camarosa', 'Camino Real', 'Campinas', 'Diamante', 'Dover', 'Festival', 'Seascape', 'Toyonoka', 'Tudla', and 'Ventana') under three managements (open field, low tunnel, and high tunnel) were evaluated. The T. urticae attack to different cultivars was influenced by managements, being low tunnel the one that provided higher infestations in the most evaluated cultivars. 'Camarosa' was the cultivar with the lower incidence of pest and 'Dover' had the higher infestation. The genotype most suitable for growing under different managements is the 'Festival' genotype, since it meets tolerance to T. urticae, high fruit yield, and phenotypic stability.