Resumo em Inglês:

Abstract This work aimed to study the effective population size and genetic gain in a population of robusta coffee (Coffea canephora Pierre) and verify the possibility of using recurrent selection. The experiment comprised 25 treatments, consisting of 21 C. canephora progenies and four C. arabica (cultivars) grown in Brazil. The experimental design was a 5x5 quadruple balanced lattice, with 24 replications, with one plant per plot. Six harvests were performed in each plant. Statistical analysis was carried out using the mixed model methodology. The analysis showed high additive genetic variability, and the magnitude of the additive components prevailed over that of the dominance components. These facts revealed the plant population liability to undergo recurrent selection, whose expected genetic gains were high. Results suggest that the effective population size and inbreeding degree throughout recurrent selection cycles be monitored. During selective cycles, cloning with weak selection is required due to few progenies.

Resumo em Inglês:

Abstract Hancornia speciosa Gomes is a fruit tree native to Brazil with potential for use in cropping systems. The objective of this study was to characterize accessions of a germplasm collection by evaluating agronomic traits. The collection was planted in 2005, in an experiment with 57 progenies and four replications, totaling 192 individual accessions from 29 natural subpopulations of four botanical varieties, from the Brazilian Cerrado. The components of variance were estimated using the restricted maximum likelihood (REML) procedure. Heritability coefficients show the potential of the collection as base population for selection programs. The trait number of fruits per plant presented the highest estimated selection gain. The accessions of H. speciosa var. cuyabensis are the ones with the greatest potential for selection based on plant size and productivity. Progenies with greater development in the juvenile phase are potentially more productive in the adult phase, allowing the early selection of superior genotypes.

Resumo em Inglês:

Abstract Many elite rice varieties have been developed in the last decades by Thai rice breeders. No information about the genetic gene pool of these elite rice varieties is available. This study evaluated the genetic relationship of 15 elite Thai rice cultivars using Indel markers. Of the 133 markers screened, 44 were polymorphic. The PIC scores ranged from 0.06 to- 0.50. By the UPGMA clustering method, they were separated into three major groups. Several markers identified specific DNA bands to certain rice cultivars, e.g., RD0305 and Rd0806 detected DNA bands specific for four photoperiod-sensitive rice cultivars. The gene pool of 15 elite Thai rice cultivars was moderately wide, and some closely related rice varieties were observed. The clustering result was consistent with the breeding pedigree. The data of this study can be used for the sustainable development of elite rice varieties in the future.

Resumo em Inglês:

Abstract Comparison between two distinct groups using a partial diallel and considering reciprocal effects has not been described in the scientific literature, limiting diallel analysis results. This study compared two groups of parents using a partial diallel, and analyzed the general and specific combining ability and reciprocal effects, divided into maternal and cytoplasmic. A partial diallel was established with nine maize hybrids, including the F1 and reciprocal hybrids for grain yield. For this application, the reciprocal effects were not significant. The proposed model would provide plant breeders with additional information to analyze partial diallel mating designs.

Resumo em Inglês:

Abstract Phytophthora root and stem rot is one of the most aggressive diseases in soybean crop. The use of resistant cultivars is the main strategy to reduce losses caused by the pathogen. This study aims to identify SNP markers associated with genes or QTLs that provide soybean with partial resistance to Phytophthora sojae. A total of 169 soybean cultivars were inoculated with Phytophthora sojae and genotyped with 3,807 SNP markers. Genome-wide association analysis was carried out via multiple linear models, followed by multiple linear regression and linkage disequilibrium analysis. Four QTLs associated with the characteristic were identified: two on chromosome 3 and two on chromosome 15. The regions containing these QTLs contain genes already annotated as providers of resistance to pathogens, in plants. The use of those markers in the selection of resistant plants can increase the efficiency of breeding programs in the development of soybean varieties resistant to P. sojae.

Resumo em Inglês:

Abstract Fusarium ear rot (FER) negatively affects maize production worldwide and poses a serious threat to human health for producing mycotoxins. The objectives of our study were to assess the factors affecting FER and fumonisin contamination in testcrosses of a maize population. In the trials, seeds of 191 testcrosses of IBMSyn4, 11 checks and 2 replications of parental lines (a total of 216 hybrids) were sown in three environments, in 2014 and 2015. FER disease intensity (DI), fumonisin contamination (FUMc) and number of ears with signs of European corn borer (ECB) attack were measured. Strong phenotypic and weak genetic correlations between DI, FUMc and ECB indicate randomness in the interaction of those traits. We detected three QTLs (chr.1, 2 and 6) for DI (LOD scores 3.77-5.06). The QTL on chr.2, confirmed across the environments, can serve as a guideline in breeding for FER resistance.

Resumo em Inglês:

Abstract The objective was to select productive and stable E. grandis families across contrasting sites in Brazil and Uruguay. Survival and growth of 130 open pollinated families were evaluated three years after planting. Survival ranged from 28 to 89% and mean annual increment from 20.5 to 48.4 m3ha- y-1. Low productivity in one site was attributed to unusually low rainfall and in the other, because of Cylindrocladium leaf disease. Heritability among families and the correlation family by environment were intermediate. Genetic pairwise correlations ranged from 0.03 to 0.81 across sites. The lowest genetic correlation between sites was observed where Cylindrocladium leaf disease occurs. Selection of top families across sites allowed selecting the best ones in each site. However, the effect of genotype-environment interactions was observed where climatic conditions are not adequate to the E. grandis, favoring the occurrence of Cylindrocladium disease.

Resumo em Inglês:

Abstract China, origin of mulberry, has rich genetic resources usually. High expense, limited space and wavering environment of usually conservation in vivo poses dangerous situation for mulberry. The concept of core collection could takes priority for conservation of mulberry. In this study, 560 accessions were used with 40 morphological descriptors and stratified sampling strategies for a core collection. The core collection consisted of 28 accessions, accounting for 5% of the whole collection. The core collection included seven accessions belonging to Morus alba, one accession belonging to M. alba var. macrophylla, four accessions belonging to M. atropurprea, one accession belonging to M. nigra, three accessions belonging to M. australis, seven accessions belonging to M. multicaulis, two accessions belonging to M. wittorum and three accessions belonging to M. bombycis. The quality of core collection exceeded the evaluation criteria and could be a prioritized collection for high efficient and long-term conservation for mulberry.

Resumo em Inglês:

Abstract The presence of stachyose and raffinose is considered an antinutritional factor for humans and monogastric animals, leading to limitations on soybean consumption as a protein source. In the present study, the effect of a mutation in the raffinose synthase 2 gene was measured on soybean quality traits. We used an F2 population with 168 soybean individuals developed by crossing four soybean lines and evaluated oil, protein, sucrose, raffinose, stachyose and fatty acid contents and their relationships. The mutation explained 69.61%, 51.81% and 31.96% of stachyose, raffinose and sucrose variation, respectively, and we were able to produce soybean with average stachyose of 0.18%. The low coefficients of determination for protein and oil indicate that the mutation can be used to increase sucrose and reduce raffinose and stachyose content without major changes in oil and protein.

Resumo em Inglês:

Abstract The current methodologies used to evaluate environmental similarities do not allow the simultaneous analysis and categorization of the environments. The objective of this study was to verify the possibility of using the Bayesian network (BN) to detect similarities between environments for plant height, lodging, and grain yield in maize. Thirteen experimental varieties were grown in six environments to measure the traits plant height, lodging, and grain yield. The BN was constructed for each trait, using the Hill-Climbing algorithm. Results were compared with the simple part of the genotypes x environments interaction, clustering by the Lin’s method and by simple correlation between environments. The Lin’s method clustered environments with predominance of complex interaction for all traits. The BN is efficient to analyze environmental similarity for plant height and grain yield since it detected the highest correlations. The BN revealed no connections among the environments that presented predominance of complex interaction.

Resumo em Inglês:

Abstract ‘Bitter’ and ‘sweet’ cassava are normally distinguished based on the hydrocyanic acid (HCN) content of their roots. Moreover, Brazilian farmers tend to select ‘sweet’ cassava based on the taste and cooking aspects. The aim of this study was to characterize chemical traits of ‘bitter’ and ‘sweet’ cassava roots of the Amazon region and to find genetic relations among accessions based on these traits. Considerable phenotypic variation was detected among the evaluated traits moisture, ashes, total soluble solids, total titratable acidity, pH, total carotenoids, free and total cyanide, crude protein, glucose, fructose, sucrose and starch. Aside from free and total cyanide, the trait means of sugars and moisture differed in ‘bitter’ and ‘sweet’ cassava and also differentiated these in different clusters in the dendrogram using the unweighted pair-group method based on arithmetic averages (UPGMA) and in the results of principal component analysis.

Resumo em Inglês:

Abstract The objectives of this study were to map genomic regions associated with QTL for aluminum (Al) tolerance in maize and determine the phenotypic effects of tolerance loci. QTL analysis for Al tolerance was carried out in a population of F2:3 progenies resulting from a cross between the contrasting lines LT 99-4 and LS 04-2. SSR (Simple Sequence Repeat) loci and AFLP (Amplified Fragment Length Polymorphism) were used to construct the linkage map and to detect QTL mapped by composite interval mapping analysis. Nine tolerance QTL among eight linkage groups (chromosomes 2, 4, 5, 6, 7, 8, 9, and 10) were mapped, which explained 70.3% of the phenotypic variance. The results confirmed three major QTL (bins 6.00, 8.05, and 10.01) that are described in the literature for Al tolerance, which accounted for most of the phenotypic variance (40.3%).

Resumo em Inglês:

Abstract The objectives of this study were to estimate the genetic progress of mass selection for white mold resistance in common bean, evaluated in a greenhouse in cycle XII of recurrent selection (900 S0 plants), and compare it with field selection in previous cycles. In addition, progress was compared with microsatellite marker-assisted selection (MAS) among S0:1 progenies. The 79 most resistant S0:1 were evaluated under field conditions using a 9×9 simple lattice design; the 21 best S0:2 and those selected from cycles IX, X, and XI were evaluated in a 6×6 triple lattice. Genetic progress was 4.25% per cycle, and 12.17% between cycles XI and XII, showing higher selection efficiency in the greenhouse. The phenotypic gain and gain from assisted selection among the S0:1 progenies were 5.08 and 1.57%, respectively, and the low value of MAS was due to only two markers (BM189 and BMD20) explaining the resistance.

Resumo em Inglês:

Abstract This work aimed to develop and validate individual SNP molecular markers previously identified in a genetic association study of resistance to Meloidogyne incognita in soybean using a microarray panel. The markers identified in the array were converted in single TaqMan® markers. The single markers were used to create an SNP genotyping protocol and establish a marker-assisted selection (MAS) routine associated with resistance to M. incognita in soybean. Out of the eight TaqMan® assays tested, three were validated for use in MAS. The MAS protocol developed in this study uses sequential selection. Initially, molecular markers are used to identify susceptible plants; subsequently, the phenotypic evaluation of plants expressing resistance genotype for the markers is carried out, resulting in the accurate identification of resistant plants. The accuracy of this approach for MAS sequential for M. incognita varied from 94 to 96%.

Resumo em Inglês:

Abstract To identify potential protein markers associated with tillering in rice, a d10 allelic mutant (JHCA) with a high-tillering dwarf phenotype and a wild-type cultivar (GLA4) with normal numbers of tillers were used to produce a hybrid (F1), and 2-DE (two-dimensional electrophoresis) analysis was conducted in seedling leaf sheaths and roots of the rice hybrid and its parents. A total of 61 protein spots representing qualitative or quantitative polymorphisms were detected. Among them, 38 spots were successfully identified as 23 different proteins by MALDI-TOF/MS. The identified proteins were further divided into P/As (presence/absence variations), PSs (position shift variations) and qVs (quantitative variations). Most of the identified polymorphic proteins exhibited tissue-specific expression. Two spot families, identified as a putative vitamin B12-independent methionine synthase and a putative phosphoglycerate mutase were found. The profiles of expression abundance of three iso-spots in each spot family showed a reciprocal relationship between the two parents.

Resumo em Inglês:

Abstract Angelonia integerrima Sprengel is a native species of the state of Mato Grosso do Sul and the Southern region (Paraná, Santa Catarina and Rio Grande do Sul) of Brazil, with features such as an unusual appearance and color of the flowers, indicating an ornamental use. To optimize the use of this species and to fill in gaps regarding its cytogenetic characterization, this study determined the chromosome number, meiotic index and pollen viability of plant individuals of four A. integerrima populations. All plant individuals of the four populations had 2n = 20 chromosomes. Still, the meiotic index of most analyzed plant individuals exceeded 90%, while pollen viability of all plant individuals was higher than 80%. These data suggest considerable cytological stability of the analyzed A. integerrima plant individuals, which may favor the selection of future genotypes for commercial purposes or their use in conservation and breeding programs of the species.

Resumo em Inglês:

Abstract Euterpe precatoria (Açaí-do-Amazonas) produces fruits of which the fresh pulp is consumed. It is almost exclusively collected by extractivist farmers, because no selected genotypes are available for the establishment of plantations. For the domestication and breeding of the species, mating system studies are needed for strategy formulation. This study evaluated the mating system of a natural population of E. precatoria. Thirteen progenies were genotyped with 13 microsatellite loci by capillary electrophoresis in an automated DNA sequencer. Estimates of single-locus and multilocus outcrossing rates were 1.0, and paternity correlation was low (r^p(m)>= 0.293). Euterpe precatoria families consist mainly of half-sibs and the reproductive strategy of the species is allogamy.

Resumo em Inglês:

Abstract UC10 is a new papaya cultivar, recommended to the southeast and northern regions of Brazil. It has a very good agronomic performance in and adaptation to these regions, with Formosa fruits of approximately 1.9 kg and yield of 260 t ha-1. The cultivar has early fruit production, and fruits have excellent flavor.

Resumo em Inglês:

Abstract Gala Fult is the first Uruguayan apple cultivar, originated by spontaneous somatic mutation of ‘Royal Gala’, identified and evaluated by nurseryman Fernando Rocca and INASE. The fruits have a complete red-blushed skin without streaks and matures more precociously than the other ‘Gala’ clones, but with the same range of edaphoclimatic adaptation.

Resumo em Inglês:

Abstract The intervarietal hybrid ‘UENF 506-11’ was derived from full-sib maize families in the 11th cycle of reciprocal recurrent selection. It produces a grain yield of 7.57 tons ha-1, and is recommended for cultivation in the North and Northwest regions of the Rio de Janeiro State.