Catorze genótipos de girassol foram utilizados para estimar valores de correlação entre treze características agronômicas em Campinas (SP), Brasil. A análise de trilha foi empregada para particionar os valores de correlação em efeitos diretos e indiretos, sobre a produtividade de grãos. Valores de correlação positivos e significativos foram obtidos entre a produtividade de grãos e as características diâmetro do capítulo (r=0,63) e massa de mil grãos (r=0,55). O diâmetro do capítulo, a porcentagem de grãos normais e a massa de mil grãos tiveram efeitos diretos positivos sobre a produtividade de grãos, podendo ser utilizados na seleção indireta, devido à sua fácil medição.Palavras-chave: germoplasma, seleção indireta, melhoramento de plantas, Helianthus annuus L. ABSTRACT CORRELATIONS AND PATH ANALYSIS IN SUNFLOWERPossible correlations among grain yield and thirteen agronomic characteristics were investigated in fourteen sunflower germplasm in a field experiment in Campinas, Brazil. In order to better understand the interrelationships among the studied variables path coefficient analysis was used for partitioning correlation in direct and indirect effects. Significant positive correlations were observed between grain yield and head diameter (r=0.63), and weight of 1000 grains (r=0.55). Head diameter, percentage of normal grains and weight of 1000 grains can be easily measured and showed positive direct effects on grain yield which led them suitable for indirect selection.

BackgroundBanana cultivars are mostly derived from hybridization between wild diploid subspecies of Musa acuminata (A genome) and M. balbisiana (B genome), and they exhibit various levels of ploidy and genomic constitution. The Embrapa ex situ Musa collection contains over 220 accessions, of which only a few have been genetically characterized. Knowledge regarding the genetic relationships and diversity between modern cultivars and wild relatives would assist in conservation and breeding strategies. Our objectives were to determine the genomic constitution based on Internal Transcribed Spacer (ITS) regions polymorphism and the ploidy of all accessions by flow cytometry and to investigate the population structure of the collection using Simple Sequence Repeat (SSR) loci as co-dominant markers based on Structure software, not previously performed in Musa.ResultsFrom the 221 accessions analyzed by flow cytometry, the correct ploidy was confirmed or established for 212 (95.9%), whereas digestion of the ITS region confirmed the genomic constitution of 209 (94.6%). Neighbor-joining clustering analysis derived from SSR binary data allowed the detection of two major groups, essentially distinguished by the presence or absence of the B genome, while subgroups were formed according to the genomic composition and commercial classification. The co-dominant nature of SSR was explored to analyze the structure of the population based on a Bayesian approach, detecting 21 subpopulations. Most of the subpopulations were in agreement with the clustering analysis.ConclusionsThe data generated by flow cytometry, ITS and SSR supported the hypothesis about the occurrence of homeologue recombination between A and B genomes, leading to discrepancies in the number of sets or portions from each parental genome. These phenomenons have been largely disregarded in the evolution of banana, as the “single-step domestication” hypothesis had long predominated. These findings will have an impact in future breeding approaches. Structure analysis enabled the efficient detection of ancestry of recently developed tetraploid hybrids by breeding programs, and for some triploids. However, for the main commercial subgroups, Structure appeared to be less efficient to detect the ancestry in diploid groups, possibly due to sampling restrictions. The possibility of inferring the membership among accessions to correct the effects of genetic structure opens possibilities for its use in marker-assisted selection by association mapping.

Brazil is one of the main centers of origin of pineapple species presenting the largest genetic variation of the Ananas genus. Embrapa Cassava and Fruits is a Brazilian Agricultural Research Corporation and has an ex-situ collection of 678 accessions of the Ananas genus and some other Bromeliaceae. The use of ornamental pineapple has increased in the last years demanding new varieties, mainly for the external market, due to the originality and colors of its tiny fruits. The main aim of the present study was describing accessions from the pineapple gene bank in order to quantify their genetic variation and identify possible progenitors to be used in breeding programs According to the results, the evaluated accessions were separated into the following categories: landscape plants, cut flower, potted plants, minifruits, foliage and hedge. The genetic distance among accessions was determined using the combined qualitative and quantitative data by the Gower algorithm. The pre-selected accessions presented genetic variation and ornamental potential for different uses. The multicategory analysis formed seven clusters through a classification method based on the average Euclidean distance between all accessions using the cut-point of genetic dissimilarity (D dg = 0.35). The genotypes A. comosus var. erectifolius were selected to be used as landscape plants, cut flower, minifruits and potted plants. Accessions of A. comosus var. bracteatus and A. macrodontes were selected as landscape plants and hedge. The highest variation was observed in A. comosus var. ananassoides genotypes, which presented high potential for use as cut flowers.

BackgroundAlthough banana (Musa sp.) is an important edible crop, contributing towards poverty alleviation and food security, limited transcriptome datasets are available for use in accelerated molecular-based breeding in this genus. 454 GS-FLX Titanium technology was employed to determine the sequence of gene transcripts in genotypes of Musa acuminata ssp. burmannicoides Calcutta 4 and M. acuminata subgroup Cavendish cv. Grande Naine, contrasting in resistance to the fungal pathogen Mycosphaerella musicola, causal organism of Sigatoka leaf spot disease. To enrich for transcripts under biotic stress responses, full length-enriched cDNA libraries were prepared from whole plant leaf materials, both uninfected and artificially challenged with pathogen conidiospores.ResultsThe study generated 846,762 high quality sequence reads, with an average length of 334 bp and totalling 283 Mbp. De novo assembly generated 36,384 and 35,269 unigene sequences for M. acuminata Calcutta 4 and Cavendish Grande Naine, respectively. A total of 64.4% of the unigenes were annotated through Basic Local Alignment Search Tool (BLAST) similarity analyses against public databases.Assembled sequences were functionally mapped to Gene Ontology (GO) terms, with unigene functions covering a diverse range of molecular functions, biological processes and cellular components. Genes from a number of defense-related pathways were observed in transcripts from each cDNA library. Over 99% of contig unigenes mapped to exon regions in the reference M. acuminata DH Pahang whole genome sequence. A total of 4068 genic-SSR loci were identified in Calcutta 4 and 4095 in Cavendish Grande Naine. A subset of 95 potential defense-related gene-derived simple sequence repeat (SSR) loci were validated for specific amplification and polymorphism across M. acuminata accessions. Fourteen loci were polymorphic, with alleles per polymorphic locus ranging from 3 to 8 and polymorphism information content ranging from 0.34 to 0.82.ConclusionsA large set of unigenes were characterized in this study for both M. acuminata Calcutta 4 and Cavendish Grande Naine, increasing the number of public domain Musa ESTs. This transcriptome is an invaluable resource for furthering our understanding of biological processes elicited during biotic stresses in Musa. Gene-based markers will facilitate molecular breeding strategies, forming the basis of genetic linkage mapping and analysis of quantitative trait loci.

The aim of this work was to evaluate the carotenoid content and genetic variability of banana accessions from the Musa germplasm collection held at Embrapa Cassava and Tropical Fruits, Brazil. Forty-two samples were analyzed, including 21 diploids, 19 triploids and two tetraploids. The carotenoid content was analyzed spectrophotometrically and genetic variability was estimated using 653 DArT markers. The average carotenoid content was 4.73 μg.g -1 , and ranged from 1.06 μg.g -1 for the triploid Nanica (Cavendish group) to 19.24 μg.g -1 for the triploid Saney. The diploids Modok Gier and NBA-14 and the triploid Saney had a carotenoid content that was, respectively, 7-fold, 6-fold and 9-fold greater than that of cultivars from the Cavendish group (2.19 μg.g -1). The mean similarity among the 42 accessions was 0.63 (range: 0.24 to 1.00). DArT analysis revealed extensive genetic variability in accessions from the Embrapa Musa germplasm bank.

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RESUMOConduziu-se este trabalho, com o objetivo de caracterizar a variabilidade genética entre 116 acessos de açaizeiro da coleção de germoplasma da Embrapa Amazônia Oriental por marcadores microssatélites (SSR). As reações foram efetuadas com base em 116 amostras de DNA, utilizando sete primers SSR. Os níveis de polimorfismo e as estimativas das distâncias genéticas de Roger foram determinados pelas frequências alélicas e agrupado pelo método UPGMA. Os sete locos SSR revelaram 42 alelos com média de 6 alelos por loco. O conteúdo de informação de polimorfismo (PIC) variou de 0,60 a 0,86 com média de 0,75 e as heterozigosidades observada (H o ) e esperada (H e ) foram de 0,54 e 0,75, respectivamente. A distância genética média entre todos os acessos foi de 0,61, variando de 0 a 0,96. O método UPGMA formou seis agrupamentos distintos delimitados pela distância genética média (dg m = 0,61). Os acessos de açaizeiro possuem alta diversidade para ser explorada em programas de melhoramento, sendo pelo menos quatro deles altamente divergentes com base nos marcadores SSR. Termos para indexação:Euterpe oleracea, germoplasma, polimorfismo, diversidade genética, SSR. ABSTRACTThe objective of this work was to characterize genetic variability among 116 accessions of assai palm of the Embrapa Eastern Amazon Germplasm Collection, were examined with microsatellite (SSR) markers. The 116 DNA sample were utilized in the reactions with seven SSR loci. The levels of polymorphism and Roger's genetic distance were estimated from allele frequencies and clustered with the UPGMA method. The seven SSR loci revealed 42 alleles, with average of 6 alleles per locus. The polymorphic information content (PIC) varied from 0.60 to 0.86, with average of 0.75 and observed (H o ) and expected (H e ) heterozygosities were 0.54 and 0.75, respectively. The mean genetic distance between all accessions was 0.61, varying from 0.00 to 0.96. The UPGMA dendrogram presented six distinct groupings, delimited by the mean genetic distance (dg m = 0.61). The accessions of assai palm possess high diversity that may be explored in breeding program and germplasm organization, with at least, four highly divergent accessions.