Resumo em Inglês:

Abstract Currently, the main control strategy for arthropod-pests in tomato cropping is the use of synthetic chemical insecticides and miticides. The study aimed to select tomato genotypes of Santa Cruz type, with determinate growth habit, which were rich in acylsugar and presented resistance to spider mite. The evaluated segregating populations were derived from interspecific crossing and were in the advanced generation F2BC2. Genotypes were assessed for acylsugars content, present in leaflets, trichomes at abaxial and adaxial parts and a repellence bioassay to the mite was performed. It was found that the genotype UFU-102-F2BC2#13 stood out in comparison to the others, showing determinate growth habit, high acylsugar content and resistance to spider mite. It was also possible to obtain genotypes that were similar to the wild specie S. pennellii, regarding the acylsugar content.

Resumo em Inglês:

Abstract Floral abnormalities in papaya cause fruit deformation and yield reduction in some periods of the year. This study aimed to evaluate 23 inbreed lines and 22 hybrids in crosses between the lines Solo and Formosa in relation to floral abnormalities, and to develop a methodology to estimate summer sterility by counting of nodes without fruits. The traits evaluated were: number of carpelloid and pentandric fruits (in March and July 2007); number of nodes without fruit and neck length (in December 2006 and April 2007); and sum of abnormalities. Hybrids presented means higher than those of the lines for all abnormalities. The capelloidy was seasonal only for lines, and the pentandry showed the lowest coefficients of determination for lines and hybrids. The number of nodes without fruit was adequate to infersummer sterility. This anomaly was the most important in the lines and hybrids.

Resumo em Inglês:

Abstract The aim of this study was to identify maize haploid plants and compare the efficiency of identification of maize haploid plants using the R1-nj morphological marker, plant vigor, flow cytometry, chromosome counting, and microsatellite molecular markers under tropical conditions. We also established a protocol for chromosome duplication in maize haploid plants. Fourteen S0:1 and seven S2:3 haploid inducer progenies were crossed with GNZ9501 in 2012/2013 and 2014/2015, respectively. Through use of the R1-nj trait, we were able to identify 552 putative haploid seeds in 2012/2013 and 260 putative haploid seeds in 2014/2015. Only 1.84% were true positives according to flow cytometry in 2012/2013. In 2014/2015, 75% of the putative haploids were true negatives according to molecular markers. Plant vigor had a high proportion of true negatives. Molecular markers and flow cytometry are more efficient in classifying plant ploidy level. Chromosome duplication was efficient in all plants.

Resumo em Inglês:

Abstract Information about combining ability is important in determining breeding strategies. The objective of this study was to estimate the general (GCA) and specific (SCA) combining abilities among twenty cotton hybrid combinations submitted to water stress, based on agronomic traits. The trails were carried out in semiarid environment (Barbalha, CE), during two years, in dry season under irrigation, and submitted to 23 days of water suppression. Wide variability was verified among parents and their hybrids, with additive effects to seed yield, lint percentage, blooming and boll weight. Dominance effect was found only to plant height. The combinations BRS 286 x CNPA 5M, BRS RUBI x CNPA 5M, FM 966 x CNPA 5M and BRS 286 x BRS Seridó showed the best SCAs and averages for the majority of the traits. In addition, at least one of their parents had high CGA. These combinations must be advanced in cotton breeding program.

Resumo em Inglês:

Abstract This study aimed to evaluate hybrids obtained by the cross among temperate × tropical elite maize lines, and to determine the genetic diversity and population differentiation of these inbred lines. Forty-nine hybrids were evaluated for seed yield, plant and ear heights, and for severity of Phaeosphaeria maydis and Exserohilum turcicum in four environments in Brazil. Hybrids were obtained from a partial diallel that involved seven tropical and seven temperate lines. Twenty-two SSR primers were used to evaluate the genetic relationship among the lines. Diallel showed the existence of significance for GCA and SCA effects; the genetic control of the traits was associated with additive and non-additive genetic effect. Results showed that exotic and previously protected temperate maize germplasm may provide novel alleles for resistance to P. maydis and E. turcicum and increase yield in tropical maize. Tropical inbred lines were allocated in different heterotic groups, suggesting an admixture condition among temperate and tropical materials.

Resumo em Inglês:

Abstract The adoption of genetically modified soybean cultivars is increasing annually around the world, which indicates the excellence of these genotypes. For soybean breeding, the use of such cultivars in a backcross program relies on the ability to detect the transgenic trait. The germination test in a moistened substrate with glyphosate is effective and of low cost, however, wonders whether this is a non-destructive method to check cultivars. The objective of this study was to apply a bioassay for detection of herbicide-tolerant seeds and to evaluate the vegetative and productive development of the plants. It was observed that both glyphosate-tolerant and glyphosate-sensitive plants were affected in the initial stages of development in accordance with the herbicide application rate. However, whereas tolerant plants fully recover both in vegetative growth and production during the cycle, sensitive plants recover partially, producing smaller plants with lower yield as a consequence of the herbicide application rate.

Resumo em Inglês:

Abstract The aim of this study was to develop a methodology that uses water deficit induction to increase the frequency of hybrids in Citrus varieties that have a high and an intermediate level of polyembryony, respectively. The experiment examined the ‘Sunki Tropical’ mandarin and ‘Rangpur Santa Cruz’ lime genotypes at three water stress intensities: 20, 40 and 100% of the pot capacity (PC). The generated fruits were harvested, and the seeds were counted. After germination, the number of nucellar and hybrid seedlings was determined. For ‘Rangpur Santa Cruz’ lime genotype, the highest hybrid frequency generated was 64.2%, which occurred at a PC of 40% and exceeded by 12% that occurring at a PC of 100%. For ‘Sunki Tropical’ mandarin, the highest observed hybrid frequency was 21.75%, which occurred at a PC of 20% and was more than double the hybrid frequency of 8.57% observed at 100% of the PC.

Resumo em Inglês:

Abstract The objective of this study was to evaluate the genotype x environment interaction and to estimate the genetic components of variance and mean using mixed models in early selection of 238 clones of Pinus taeda propagated by somatic embryogenesis. The experiment consisted of a complete blocks design, with 12 replications, with one plant per plot, in four environments, at 1, 3, and 4 years of age. Estimates of heritability and of genetic gains in the evaluated environments showed good prospects for selection of superior genotypes. The effect of genotype x environment interaction was pronounced for all traits investigated. With the simultaneous selection for stability and adaptability, 10% genetic gain was obtained in relation to the mean of the commercial controls. This estimated gain indicates that the somatic embryogenesis technique has been effective in propagation of clones with good productive potential.

Resumo em Inglês:

Abstract The species Tropaeolum pentaphyllum Lam. (batata-crem or crem) is of great economic and medicinal importance. For being an endangered species, the knowledge of its genetic variability is necessary. Considering the lack of cytological studies on this species, this work describes the chromosome numbers, the meiotic behavior, the meiotic index, and the viability of the pollen grains of three populations of T. pentaphyllumm from Rio Grande do Sul, Brazil. The three populations presented 2n = 28 chromosomes. Meiotic behavior was regular, with low abnormality frequency (<1%), which culminated in IMx> 90% in the three accessions. This meiotic stability resulted in high production of viable pollen grains, which will favor the use of these accessions in selection programs for commercial purposes, conservation and sustainable use.

Resumo em Inglês:

Abstract Globe artichoke (Cynara cardunculus var. scolymus) is a cross-pollinated, highly heterozygous species, which is conventionally propagated vegetatively. A scheme is described here which combines phenotypic with genotypic selection to fast track the development of a seed-propagated variety. The scheme was tested by making three selections, on a phenotypic basis, from a Brazilian seed-propagated variety showing an high phenotypic variation. The genetic relatedness as well as the heterozygosity of the material in study, in respect to standard variety representatives, was initially assessed with a wide set of microsatellite markers. Afterwards, an AFLP-based selection demonstrated to provide a practical and cheap means of conducting marker assisted breeding, which can be easily adopted also in laboratories of small seed companies. The selection approach described here could be readily adopted also to convert current vegetatively propagated landraces into seed-propagated varieties.

Resumo em Inglês:

Abstract To date, no studies on the inheritance of Fusarium spp. ear rot resistance in popcorn are available. The purpose of this paper was to investigate the additive-dominance model to estimate the genetic components of variance, heritability and the inheritance pattern in a diallel for popcorn, by Hayman’s approach. The experiment was carried out in two environments, using eight parent lines. The following traits were measured: grain yield (GY), popping expansion (PE), incidence of ears infected by Fusarium (FusIE), total number of kernels infected by fungi (FunIK) and total number of kernels infected by Fusarium spp. (FusIK). The results indicated that the incidence of FusIK (Fusarium-infected kernels), FunIK (fungus-infected kernels), and FusIE (Fusarium-infected ears) is controlled by dominant genes. Parent L77 had a high number of favorable alleles for all resistance-related traits, as well as for PE. The strategy recommended for reduction of FunIK, FusIK, and FusIE consists of exploiting hetorosis using inbred lines with favorable alleles.

Resumo em Inglês:

Abstract Pennisetum purpureum Schum. has been a key alternative as an energy source in Brazil because of its higher dry matter accumulation and fiber content. This research aimed to select superior individuals of P. purpureum for energy purposes using among-and-within family selection. The study was carried out in Campos dos Goytacazes- RJ (Brazil), using eight full-sib families. Plants were individually assessed during two pasture cuttings, one in 2014, and another in 2015. The dry matter production (DMP) was correlated with the number of tillers, stem diameter, plant height, and neutral detergent fiber content. Plant selection criteria in both cuts were through direct and indirect selections, and Smith and Hazel index. A joint analysis of variance showed significant differences for all five traits assessed in both cuts. The results achieved with Smith and Hazel index were promising for simultaneous selection of the evaluated traits, favoring selection of superior families and individuals them.

Resumo em Inglês:

Abstract In this study, we quantify and document the distribution and organization of cpSSRs in the chloroplast genome of 31 Eucalyptus species. Our sample included all previously sequenced plastomes of Eucalyptus species available from the NCBI online database. We processed the complete cpDNA sequences and identified mono-, di-, tri-, tetra-, penta-, and hexanucleotide cpSSRs, with the majority of cpSSRs classified as mononucleotide. After genome microsatellite selection, we evaluated the microsatellites for coding and non-coding regions and cpSSRs were predominantly identified in non-coding regions of cpDNA for all nucleotide types. Penta- and hexanucleotide cpSSRs were the least frequent types of microsatellites. We also developed and virtually amplified 60 primers pairs that can be used in studies of Eucalyptus species. Thus, these cpSSR regions can be used in studies assessing the ecology, breeding, and conservation of the genus.

Resumo em Inglês:

Abstract The amylose content (AC) of rice is a key determinant of the grain cooking and eating quality. The Waxy (Wx) gene, which encodes granule-bound starch synthase I (GBSSI), is the major gene controlling AC in rice. The A - C substitution in exon 6 (Ex6A/C) alters the amino acid codon from serine to tyrosine and is associated with intermediate-AC rice (Wx-in). In this paper, we reported a perfect functional marker for the SNP Ex6A/C of Wx-in based on polymerase chain reaction with confronting two-pair primers (PCR-CTPP) in a single-tube PCR assay. Specificity and applicability of the PCR assay were verified in a Chinese mini core collection (MCC) of Oryza sativa L. and a breeding population. Were commend the use of the simple, inexpensive assay for routine genotyping for intermediate AC in the breeding population or discrimination of Wx-in genotypes in rice germplasm.

Resumo em Inglês:

Abstract The aim of this study was to identify resistance to bacterial halo blight in Arabica coffee lines carrying Coffea racemosa genes. Eighteen Arabica coffee lines derivative from the genotype C1195-5-6-2, and the cultivars IAPAR 59 and IPR 99 were evaluated for resistance to bacterial halo blight in two trials carried out in field conditions, in Londrina, PR, Brazil. The cultivars Mundo Novo IAC 376-4 and Catuaí Vermelho IAC 81 were included as susceptible controls. Ten lines and the cultivar IAPAR 59 showed resistance to bacterial halo blight. The cultivar IPR 99 presented intermediate reaction, and the controls were very susceptible. This is the first study to show that lines derivative from the genotype C1195-5-6-2, which has C. racemosa genes, could be a source of resistance to bacterial halo blight in coffee breeding programs.

Resumo em Inglês:

Abstract Annatto (Bixa orellana) is a tropical crop native to the Americas with Amazonia as the likely center of origin of domestication. Annatto is important because it produces the dye bixin, which is widely used in the pharmaceutical, food, cosmetic and textile industries. A total of 32 microsatellite loci were isolated from a microsatellite-enriched genomic library, of which 12 polymorphic loci were used to characterize four populations of B. orellana and B. orellana var. urucurana, the wild relative. Higher genetic diversity estimates were detected for the wild populations when compared to the cultivated populations. Also, higher apparent outcrossing rates were found for the two wild than the cultivated populations. These results indicate a mixed mating system for the species. All markers described herein have potential to be used in further studies evaluating the genetic diversity, population dynamics, domestication, breeding, and conservation genetics of annatto.

Resumo em Inglês:

Abstract CD 1303 is a cultivar indicated for the wheat-producing regions 1, 2 and 3 of the states of Rio Grande do Sul, Santa Catarina and Paraná. It has an early cycle, a short stature and high productive potential (mean of 4311 kg ha-1).

Resumo em Inglês:

Abstract UENF 2014 is a new common bean cultivar from the black commercial group, developed by UENF. The cultivar is adapted to the Northern and Northwestern regions of the Rio de Janeiro state and presents a good performance, mainly for high grain yield, high stability and wide adaptation to these regions.