Resumo em Inglês:

Abstract One of the major challenges in sugarcane breeding programs is an efficient selection of genotypes in the initial phase. The purpose of this study was to compare modelling by artificial neural networks (ANN) and linear discriminant analysis (LDA) as alternatives for the selection of promising sugarcane families based on the indirect traits number of sugarcane stalks (NS), stalk diameter (SD) and stalk height (SH). The analysis focused on two models, a full one with all predictors, and a reduced one, from which the variable SH was excluded. To compare and assess the applied methods, the apparent error rate (AER) and true positive rate (TPR) were used, derived from the confusion matrix. Modeling with ANN and LDA can be used successfully for selection among sugarcane families. The reduced model may be preferable, for having a low AER, high TPR and being easier to obtain in operational terms.

Resumo em Inglês:

Abstract Potato virus Y (PVY) is considered one of the most important pathogens in potato crop. The objective of this study was to estimate the allele dosage of Ry genes and select clones with multiple copies of resistance alleles to be used as parents in potato breeding programs. Seven clonal families were genotyped, including five parents with resistance to PVY. For the allele Ryadg, based on the marker RYSC3, four parents are simplex, and one is duplex. For the allele Rysto, based on the marker M45, two parents are simplex and one is duplex. For two parents, the observed frequencies of the allele Rysto did not statistically adjust to any of the proposed genotypic constitutions. Based on the results obtained, both markers must be used in marker assisted selection for resistance to PVY, in order to decrease the error of discarding clones with only one of the alleles.

Resumo em Inglês:

Abstract In this study we aimed to investigate genetic control of the emergence speed index (ESI) and percentage of canopy coverage (PCC) in plants, and to evaluate whether these traits can be used to identify common bean plants that rapidly provide canopy coverage. Plants from a segregating population and progenies from a cross between a large leaf line and a small leaf line were evaluated. It was observed variability for ESI, however, the low magnitude of heritability indicates that the probability of success from selection is not high. The additive effect was predominant in genetic control of PCC. Nevertheless, this trait is highly affected by the genotype by environment interaction, which makes success from selection even more difficult. The association between ESI and PCC was also low. This information can guide decision making in programs that aim at fast canopy coverage in common bean.

Resumo em Inglês:

Abstract The aim of this study was to perform chromosome counts and nuclear DNA quantification of the unconventional vegetables species: bertalha (Basella alba L.), vinagreira verde (Hibiscus sabdariffa L.), azedinha (Rumex acetosa L.), peixinho (Stachys byzantina K. Koch), and capuchinha (Tropaeolum majus L.). Metaphase chromosomes were obtained from the pre-treatment of root meristem with 8-hydroxyquinoline or colchicine and lides were prepared by the flame-drying technique and stained with 5% Giemsa. DNA quantification was performed by flow cytometry. Chromosome number and DNA content (pg) estimated for each species were: Rumex acetosa: 2n=2x=14 and 7.04 pg; Basella alba: 2n=2x=44 and 7.05 pg; Tropaeolum majus: 2n=2x=28 and 2.08 pg; Stachys byzantine: 2n=2x=30 and 1.54 pg, and Hibiscus sabdariffa: 2n=4x=72 and 5.12 pg.

Resumo em Inglês:

Abstract The objective of this study was to select a population of sugarcane clones to develop energy cane cultivars. The genotypic means of 124 clones were estimated for the yield-related traits: mean number of stalks per plant (NS), mean stalk weight (MSW), fiber content (FIB), lignin content (LIG), and sucrose content in cane juice (SPC). From these data, the traits tons of cane per hectare (TCH), tons of fiber per hectare (TFH) and tons of lignin per hectare (TLH) were estimated. The clone effects were statistically significant (p <0.01) for all traits except TLH and LIG. Clone UFV09251 had the highest genotypic values ​​for TFH and TCH. Clone UFV09270 had a high fiber content (15.04%) and clone UFV09225 a high sucrose content (14.05%). The correlation between TFH and TCH was high (0.89). Clone UFV09251 is highly promising as energy cane cultivar, for producing most TCH and FIB.

Resumo em Inglês:

Abstract Understanding the effects of nanoparticles on edible crops is a matter of importance, since nanoparticles are often released and spread in the environment because of extensive research. This study aimed to examine the effect of silver nanoparticles on protein and carbohydrate contents of Pisum sativum L. seed. Spherical crystalline silver nanoparticles were synthesized from aqueous root bark extract of Berberis lycium Royle. Three pea varieties (Climax, Meteor and PF-400) were treated with four concentrations of silver nanoparticles (0, 30, 60, and 90 ppm) and three modes of application, in a randomized complete block design with three replications, in the 2013-14 and 2014-15 growing seasons. Seeds were harvested at the end of the growing seasons and analyzed for total proteins and carbohydrates. A significant increase in protein and carbohydrate contents of harvested seeds was recorded. This study shows that the application of silver nanoparticles might revolutionize agriculture in the future.

Resumo em Inglês:

Abstract The study aimed at investigating the anatomic and DNA content characteristics of 12 Anthurium genotypes. A large genomic amplitude was observed in the genotypes, ranging from 4.95 to 22.74 pg of DNA. Differences in DNA content, assessed by flow cytometry, allowed the differentiation between the genotypes A. andraeanum, A. affine, A. bomplandii, and A. gracile and the hybrid (A. lindmanianum × A. guianesis) and clustered the group A. raimundii, plowmanii and jemanii of IFT 258, in all analyses. Anatomical studies clustered the genotypes A. andraeanum (Astral and Rubi) and distinguished the hybrid and A. bomplandii from the other genotypes, with anatomical features specific to each genotypes. Cluster analysis allowed grouping of the genotypes A. raimundii and A. affine, bomplandii and gracile, A. jemanii and plowmanii, and the cultivars Astral and Rubi, and isolated the hybrid. Demonstrated the importance of grouping in the diagnosis of species belonging to the genus Anthurium.

Resumo em Inglês:

Abstract We proposed a population structure correction for genome-wide selection based on covariance analysis via eigenvector (EVG) decomposition. The agreement between the predicted and true breeding values was evaluated by independent cross-validation data sets. Other correction methods such as correction via principal components, best linear unbiased prediction, and deregressed phenotype were also evaluated. Based on different simulation scenarios, the proposed EVG out performed the other methods in the prediction of accuracy.

Resumo em Inglês:

Abstract This study aimed to identify promising arabica coffee genotypes for organic systems. The experiments were arranged in a randomized block design, with 30 genotypes and three replications. The adaptability and stability analysis was carried out using the modified centroid method, considering the mean yield of two biennia (2005/2006 and 2006/2007, 2007/2008 and 2008/2009) in three municipalities (Araponga, Espera Feliz, and Tombos), totaling six environments. Significant genotype x environment interaction was observed for yield, and the municipality of Espera Feliz was the only favorable environment. Genotypes were classified into four of the seven groups proposed by the modified centroid method: maximum general adaptability (I), minimum adaptability (IV), mean general adaptability (V), and mean specific adaptability to favorable environments (VI). Cultivars IBC Palma 1, CatucaíAmarelo24/137, Sabiá 708, and H 518 are widely adapted, stable, productive and suitable for organic farming.

Resumo em Inglês:

Abstract Adaptability is the yield response of cassava genotypes to environmental improvement, and stability is the predictability of this response to variations. The objective of this study was to evaluate the yield stability and adaptability of cassava varieties and clones using the AMMI (Additive Main Effects and Multiplicative Interaction) methodology and auxiliary tools as supplementary genotype and environment. The responses of 24 cassava genotypes were evaluated in three environments located in the state of Alagoas, Brazil, in randomized blocks design, with 24 treatments and three replications. The effects of genotype and genotype x environment interactions significantly influenced yield. Genotypes differed regarding the adaptability and stability of yield response, and the varieties Cria Menino and Preta do Araripe were considered ideal genotypes due to high adaptability and yield stability. Among the three tested environments, Limoeiro de Anadia was the best since it presented high yield, phenotypically stable genotypes for cassava breeding programs.

Resumo em Inglês:

Abstract Genetic diversity is an essential factor for the success of any plant breeding program and should be considered to ensure genetic gain through breeding. In Brazil, research on the genetic diversity and population structure of soybean is required since the species is an important commodity of the country. The study addressed the genetic diversity and population structure of 77 soybean genotypes using 35 SSR markers. The estimate of the diversity index showed that the level of genetic diversity in the soybean collection is low. Similarly, the Jaccard coefficient and Bayesian model based on clustering analysis confirmed the low diversity among soybean genotypes, providing evidence for the assumption of a genetic bottleneck effect on Brazilian soybean genotypes. The results also reinforced the importance of finding and incorporating new genetic resources of soybean in the genetic pool of Brazilian soybean to warrant genetic gain in soybean breeding in the future.

Resumo em Inglês:

Abstract The objective of this study was to analyze the genetic diversity among and within populations of Brazil nut by Amplified Fragment Length Polymorphism markers. Five populations with 30 plants each of the state of Amazonas, Brazil, two populations from the Farm Aruanã (Aruanã Carolina and Aruanã Brastor), in Itacoatiara, one from the municipality of Parintins and two from the municipality of Manaus (Instituto Federal do Amazonas - IFAM and Manaus Airport) were evaluated. Four primer combinations were used and 306 polymorphic bands (93.3%) were obtained. Genetic differentiation within and among populations was tested by analysis of molecular variance. The presence of genetic divergence was greater within populations (51.88%) than among populations (48.11%) and the Fst value was 0.48. Two groups were formed by interpopulation grouping: the first consisted of populations from plantations in Aruanã Carolina, Aruanã Brastor and Manaus IFAM, and the second of natural populations from Parintins and Manaus Airport.

Resumo em Inglês:

Abstract The objectives were to map genomic regions associated with quantitative trait loci (QTL) to anthracnose leaf blight (ALB) in tropical maize, and to determine the effects of the loci on resistance to the pathogenic fungus Colletotrichum graminicola (Ces.). QTL analysis to ALB was carried out in a population of F2:3 progenies resulting from the cross between the contrasting lines LR 04-2 and LS 95-1. Seventeen QTL were located by mapping analysis by composite interval on eight chromosomes. Four QTL mapped on chromosomes 9 (1 QTL) and 10 (3 QTL) were the most stable, detected in at least two experiments, and represented the most part of the phenotypic variation (27.7 to 54.3%) of resistance. The majority of QTL mapped were associated to specific severity evaluations/development stage of maize growth, and may explain the quantitative inheritance of resistance of tropical maize to ALB.

Resumo em Inglês:

Abstract Cotton cultivar BRS 368RF was developed by EMBRAPA in a partnership with the Bahia Foundation, aiming to create high-yielding germplasm by adding transgenic traits addressed to Brazilian Savanna (cerrado) of the Northeast and North regions. BRS 368RF is a midseason cultivar and has yield stability and transgenic tolerance to glyphosate.

Resumo em Inglês:

Abstract ‘IPR 102’ is a coffee cultivar derivative from a cross between “Catuaí” and “Icatu”. ‘IPR 102’ is a dwarf cultivar (medium size) with high rusticity, late ripening cycle, and it is resistant to bacterial halo blight and partial resistant to coffee leaf rust.

Resumo em Inglês:

Abstract Coffee tree is a shrub with dimorphic branches. The orthotropic stem grows vertically with two near-horizontal plagiotropic branches, per node, in opposite phyllotaxy. The consecutive nodes of the orthotropic stem are organized in parastichies. We report here mutant plants of Coffea arabica with triple plagiotropic branch, resulted from the whorled phyllotaxy of the orthotropic stem. In mutant plants three plagiotropic branches in the same node are separated by angles of approximately 120o, while in normal plants two plagiotropic branches in the same node are separated by angles of approximately 180o. In mutant plants the angles of the parastichies increase approximately 50o clockwise between consecutive nodes, while in normal plants the angles increase approximately 87o. The plant architecture is changed. The triple plagiotropic branch is a putative mutant with potential to be explored in coffee breeding programs. The hypotheses for the origin of the mutation and the research perspectives are discussed.