Marker-assisted selection integrated to the embrapa common bean breeding program.

The establishment of a specific Marker-Assisted Selection Facility at the Embrapa Rice and Beans Biotechnology Laboratory, in 2014, has better supported the routine analysis with molecular markers demanded by the Embrapa Common Bean Breeding Program. In addition, it has also supported other Embrapa plant breeding programs, such as rice and cotton.

Natural variation in expression of genes associated with carotenoid biosynthesis and accumulation in cassava (Manihot esculenta Crantz) storage root.

ABSTRACT: BACKGROUND: Cassava (Manihot esculenta Crantz) storage root provides a staple food source for millions of people worldwide. Increasing the carotenoid content in storage root of cassava could provide improved nutritional and health benefits. Because carotenoid accumulation has been associated with storage root color, this study characterized carotenoid profiles, and abundance of key transcripts associated with carotenoid biosynthesis, from 23 landraces of cassava storage root ranging in color from white-to-yellow-to-pink. This study provides important information to plant breeding programs aimed at improving cassava storage root nutritional quality. RESULTS: Among the 23 landraces, five carotenoid types were detected in storage root with white color, while carotenoid types ranged from 1 to 21 in storage root with pink and yellow color. The majority of storage root in these landraces ranged in color from pale-to-intense yellow. In this color group, total ß-carotene, containing all-E-, 9-Z-, and 13-Z-ß-carotene isomers, was the major carotenoid type detected, varying from 26.13 to 76.72 %. Although no ?-carotene was observed, variable amounts of a ?-ring derived xanthophyll, lutein, was detected; with greater accumulation of ?-ring xanthophylls than of ß-ring xanthophyll. Lycopene was detected in a landrace (Cas51) with pink color storage root, but it was not detected in storage root with yellow color. Based on microarray and qRT-PCR analyses, abundance of transcripts coding for enzymes involved in carotenoid biosynthesis were consistent with carotenoid composition determined by contrasting HPLC-Diode Array profiles from storage root of landraces IAC12, Cas64, and Cas51. Abundance of transcripts encoding for proteins regulating plastid division were also consistent with the observed differences in total ß-carotene accumulation. CONCLUSIONS: Among the 23 cassava landraces with varying storage root color and diverse carotenoid types and profiles, landrace Cas51 (pink color storage root) had low LYCb transcript abundance, whereas landrace Cas64 (intense yellow storage root) had decreased HYb transcript abundance. These results may explain the increased amounts of lycopene and total ß-carotene observed in landraces Cas51 and Cas64, respectively. Overall, total carotenoid content in cassava storage root of color class representatives were associated with spatial patterns of secondary growth, color, and abundance of transcripts linked to plastid division. Finally, a partial carotenoid biosynthesis pathway is proposed.

Evaluation of the reaction of watermelon parent and F1 plants to Meloidogyne enterolobii.

The aim of this study was to evaluate the performance of progenies from Citrullus lanatus var. lanatus (cultivated watermelons) when crossed with progenies from C. lanatus var. citroides (fodder watermelon with a historic of resistance to the nematode Meloidogyne enterolobii). The parents and their F1s were evaluated for resistance to this nematode. In the initial stages of eleven treatments, watermelon seedlings plantlets were transplanted to plastic bags of six kilograms once the first leaves developed. Ten inoculated plants with 5,200 eggs in the soil near the stem of the plant and four non-inoculated ones were used in each treatment, in a complete block design. Sixty-two days after sowing, the following characteristics were evaluated: the length of the aerial part of the plant (LAP, in m), fresh mass of the aerial part (FMAP, in g), root fresh mass (RFM, in g), egg number (EN) and reproduction factor (RF). A comparison between the averages of inoculated and non-inoculated plants was performed using Scott-Knott test at 5% and the diallelic analysis was performed using the GENES program. The morphological characteristics did not allow for the identification of the parent plants or the F1s with respect to nematode resistance, but the variables EN and RF were useful for such identification. The analyses of the general and specific combining abilities indicate highly significant effects with respect to this resistance, showing additive gene effects as well as dominance and epistatic gene effects, allowing for identification of parents and F1s that can be used in watermelon breeding programs to improve resistance to the M. enterolobii.

Genome selection in fruit breeding: application to table grapes.

Genomic selection (GS) has recently been proposed as a new selection strategy which represents an innovative paradigm in crop improvement, now widely adopted in animal breeding. Genomic selection relies on phenotyping and high-density genotyping of a sufficiently large and representative sample of the target breeding population, so that the majority of loci that regulate a quantitative trait are in linkage disequilibrium with one or more molecular markers and can thus be captured by selection. In this study we address genomic selection in a practical fruit breeding context applying it to a breeding population of table grape obtained from a cross between the hybrid genotype D8909-15 (Vitis rupestris × Vitis arizonica/girdiana), which is resistant to dagger nematode and Pierce?s disease (PD), and ?B90-116?, a susceptible Vitis vinifera cultivar with desirable fruit characteristics. Our aim was to enhance the knowledge on the genomic variation of agronomical traits in table grape populations for future use in marker-assisted selection (MAS) and GS, by discovering a set of molecular markers associated with genomic regions involved in this variation. A number of Quantitative Trait Loci (QTL) were discovered but this method is inaccurate and the genetic architecture of the studied population was better captured by the BLasso method of genomic selection, which allowed for efficient inference about the genetic contribution of the various marker loci. The technology of genomic selection afforded greater efficiency than QTL analysis and can be very useful in speeding up the selection procedures for agronomic traits in table grapes.

Predictive ability of Genomic Estimated Family Values (GEFV).

Genomic selection (GS) has been used to compute genomic estimated breeding values (GEBV) of individuals; however, it has only been applied to animal and major plant crops due to high costs. Besides, breeding and selection is performed at the family level in some crops. We aimed to study the implementation of genome-wide family selection (GWFS) in two loblolly pine (Pinus taeda L.) populations: i) the breeding population CCLONES composed of 63 families (5-20 individuals per family), phenotyped for four traits (stem diameter, stem rust susceptibility, tree stiffness and lignin content) and genotyped using an Illumina Infinium assay with 4740 polymorphic SNPs, and ii) a simulated population that reproduced the same pedigree as CCLONES, 5000 polymorphic loci and two traits (oligogenic and polygenic). In both populations, phenotypic and genotypic data was pooled at the family level in silico. Phenotypes were averaged across replicates for all the individuals and allele frequency was computed for each SNP. Marker effects were estimated at the individual (GEBV) and family (GEFV) levels with Bayes-B using the package BGLR in R and models were validated using 10-fold cross validations. Predicted ability, computed by correlating phenotypes with GEBV and GEFV, was always higher for GEFV in both populations, even after standardizing GEFV predictions to be comparable to GEBV. Results revealed great potential for using GWFS in breeding programs that select families, such as most outbreeding forage species. A significant drop in genotyping costs as one sample per family is needed would allow the application of GWFS in minor crops.

Adaptabilidade e estabilidade de progênies de meios-irmãos de pinhão-manso em diferentes regiões do Brasil.

RESUMO: Programas de melhoramento do pinhão-manso (Jatropha curcas L.) intensificaram-se nos últimos cinco anos, tendo sido selecionadas, localmente, plantas em diversas regiões do Brasil. O objetivo deste trabalho foi quantificar a interação genótipos x ambientes da produção de grãos de pinhão-manso, avaliada em três regiões brasileiras, e o progresso genético obtido com a seleção. A partir de progênies de meios-irmãos, selecionadas pela Embrapa Semiárido e pela EPAMIG, foram instalados, no ano de 2008, três testes de progênies, nos municípios de Planaltina, DF, Nova Porteirinha, MG e Pelotas, RS, utilizando-se delineamento de blocos ao acaso, com três repetições e cinco plantas por parcela. Como testemunhas foram utilizadas sementes de plantas não selecionadas e um dos materiais genéticos comercializados no Brasil. A interação genótipo x ambiente foi significativa. Foram identificadas oito progênies de adaptabilidade geral, três progênies de baixa adaptabilidade, duas progênies de adaptabilidade específica a ambientes favoráveis e duas progênies de adaptabilidade específica a ambientes desfavoráveis, em diferentes regiões do Brasil. As estimativas de progresso genético indicam eficiência da seleção massal, com ganhos de 28, 76 e 177%, nos municípios de Planaltina, DF, de Nova Porteirinha, MG, e de Pelota, RS, respectivamente. Observa-se que os ganhos de seleção obtidos pelo método centroide são mais equilibrados entre ambientes e, por isso, preferíveis. As novas médias, estimadas com o plantio das progênies selecionadas, em toneladas por hectare, são de 2,34 ton.ha-1, em Planaltina, DF; de 2,37 ton.ha-1, em Nova Porteirinha, MG, e de 2,09 ton.ha-1 , em Pelotas, RS. ABSTRACT: Physic nut (Jatropha curcas L.) breeding programs have intensified in the past five years, locally selecting plants from various Brazilian regions. The objective of this study was to quantify the genotype x environment interaction of the physic nut grain production and the genetic progress obtained with the selection. From Half-sib progenies selected by Embrapa and EPAMIG, in 2008, three progeny trials were installed in the cities of Planaltina-DF, Nova Porteirinha-MG and Pelotas-RS, using a randomized block design with three replications of five plants per plot. Non-selected plant seeds and genetic material commercialized in Brazil were used as control. The genotype x environment interaction was significant for the J. curcas grain yield expression. We identified eight progenies of broad adaptability, three progenies of low adaptability, two progenies of specific adaptability to favorable environments and two progenies of specific adaptability to unfavorable environments of different Brazilian regions. Estimates of genetic progress indicate mass selection efficiency, with genetic gains of 28%, 76% and 177% in the Planaltina-DF, New Porteirinha-MG and Pelotas-RS, respectively. The genetic gains obtained by the centroid method were more balanced among environments, and therefore, preferable. The new means estimated with the cultivating of the selected progenies are: 2.34 ton.ha-1 in Planaltina-DF, 2.37 ton.ha-1 in Nova Porteirinha- MG and 2.09 ton.ha-1 in Pelotas-RS.

Qualidade de sementes de girassol na safrinha do Distrito Federal.

RESUMO: O presente trabalho teve como objetivo avaliar, através de diferentes testes, a qualidade fisiológica de sementes de girassol na safrinha do Distrito Federal. Os testes foram realizados no Laboratório de Sementes da Faculdade de Agronomia e Veterinária ? FAV, da Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Brasília, DF, em 2014. Foram realizados testes de germinação padrão em areia e em papel, peso da matéria verde e da matéria seca, envelhecimento acelerado, condutividade elétrica e lixiviados de potássio. Foram encontradas diferenças significativas entre os genótipos para as todas as características avaliadas. Dentre os genótipos avaliados, os híbridos que se destacaram quanto a qualidades fisiológicas desejáveis pelos testes de germinação, condutividade elétrica e lixiviação de potássio foram BRS G42 e SYN 045. Materiais genéticos foram identificados no trabalho para possível exploração em programas de melhoramento. ABSTRACT: This study aims to evaluate, through different tests, the seed physiological quality of sunflower in the second crop in the Brazilian savannah. The tests were carried on in the Seed Laboratory of Veterinary and Agriculture Faculty of University of Brasilia, in 2014. The tests were seedling emergence in sand and paper, green and dry matter weight, accelerated aging, electrical conductivity and potassium leached. Related to the evaluated characteristics, significant differences were found between genotypes. Among them, the hybrids that stood out for the physiologic characteristics through the germination test, electric conductivity and potassium leaching were BRS G42 and SYN 045. Genetic materials were identified in this study for a possible exploration in breeding programs.

Evolution of methodology for the study of adaptability and stability in cultivated species.

The GxE interaction only became widely discussed from evolutionary studies and evaluations of the causes of behavioral changes of species cultivated in environments. In the last 60 years, several methodologies for the study of adaptability and stability of genotypes in multiple environments trials were developed in order to assist the breeder's choice regarding which genotypes are more stable and which are the most suitable for the crops in the most diverse environments. The methods that use linear regression analysis were the first to be used in a general way by breeders, followed by multivariate analysis methods and mixed models. The need to identify the genetic and environmental causes that are behind the GxE interaction led to the development of new models that include the use of covariates and which can also include both multivariate methods and mixed modeling. However, further studies are needed to identify the causes of GxE interaction as well as for the more accurate measurement of its effects on phenotypic expression of varieties in competition trials carried out in genetic breeding programs.

Karyotype and genome size in Euterpe Mart. (Arecaceae) species.

Euterpe (Martius, 1823), a genus from Central and South America, has species with high economic importance in Brazil, because of their palm heart and fruits, known as açaí berries. Breeding programs have been conducted to increase yield and establish cultivation systems to replace the extraction of wild material. These programs need basic information about the genome of these species to better explore the available genetic variability. The aim of this study was to compare E. edulis (Martius, 1824), E. oleracea (Martius, 1824) and E. precatoria (Martius, 1842), with regard to karyotype, type of interphase nucleus and nuclear DNA amount. Metaphase chromosomes and interphase nuclei from root tip meristematic cells were obtained by the squashing technique and solid stained for microscope analysis. The DNA amount was estimated by flow cytometry. There were previous reports on the chromosome number of E. edulis and E. oleracea, but chromosome morphology of these two species and the whole karyotype of E. precatoria are reported for the first time. The species have 2n=36, a number considered as a pleisomorphic feature in Arecoideae since the modern species, according to floral morphology, have the lowest chromosome number (2n=28 and 2n=30). The three Euterpe species also have the same type of interphase nuclei, classified as semi-reticulate. The species differed on karyotypic formulas, on localization of secondary constriction and genome size. The data suggest that the main forces driving Euterpe karyotype evolution were structural rearrangements, such as inversions and translocations that alter chromosome morphology, and either deletion or amplification that led to changes in chromosome size.

Adaptação climática de progênies de Pinus spp oriundas de polinização controlada.

2015

Tamanho efetivo populacional e diversidade genética em progênies de Pinus caribaea var. hondurensis.

2015

Desempenho inicial em crescimento de Cordia trichotoma em teste de progênies.

2015

Selection between and within full-sib sugarcane families using the modified BLUPIS method (BLUPISM).

2016

Association mapping provides insights into the origin and the fine structure of the sorghum aluminum tolerance locus, AltSB.

2014

Identification of common bean resistant sources to angular leaf spot disease in a brazilian germplasm collection.

The aim of this study was to identify sources of resistance in the germplasm collection providing information of potential sources of resistance to introduce in breeding programs.