Coffea canephora: Heterotic Crosses Indicated by Molecular Approach.

The genus Coffea comprises more than 100 species, of which the most commercially important are Coffea arabica and Coffea canephora. The latter is a self-incompatible plant with high natural genetic variability. The detection of polymorphism at the DNA level by molecular markers allowed significant progress with the selection of superior plants. The objective of this study was the molecular characterization of C. canephora using microsatellite markers. To this end, a population of forty-four C. canephora genotypes and one C. arabica genotype, was evaluated with 21 primers. These primers identified 61 alleles in the population and between 2 and 5 alleles per locus. The information index indicated a high level of polymorphism of the analyzed markers. According to the observed and expected heterozygosity, the genetic diversity in the population is high. The overall inbreeding coefficient of the population detected high heterozygosity and zero inbreeding within this population. Genetic diversity among the accessions was also evaluated by the unweighted pair-group method based on arithmetic averages (UPGMA). Six groups were formed based on Mojena's cutting rule and three using the Bayesian approach. These results confirmed the existence of genetic diversity, genetic variability and a potential for selection in future breeding efforts involving the 45 genotypes studied.

Bayesian ridge regression shows the best fit for SSR markers in Psidium guajava among Bayesian models.

Markers are an important tool in plant breeding, which can improve conventional phenotypic breeding, generating more accurate information outcoming better decision making. This study aimed to apply and compare the fit of different Bayesian models BRR, BayesA, BayesB, BayesB (setting the value from very low to [Formula: see text] = [Formula: see text]), BayesC and Bayesian Lasso (LASSO) for predictions of the genomic genetic values of productivity and quality traits of a guava population. The models were fitted for traits fruit mass, pulp mass, soluble solids content, fruit number, and production per plant in the genomic prediction with SSR markers, obtained through the CTAB extraction method with 200 primers. The Bayesian ridge regression model showed the best results for all traits and was chosen to predict the individual's genomic values according to the cross-validation data. A good stabilization of the Markov and Monte Carlo chains was observed with the mean values close to the observed phenotypic means. Heritabilities showed good predictive accuracy. The model showed strong correlations between some traits, allowing indirect selection.

Genetic structuring of segregating populations of Psidium spp resistant to the southern root-knot nematode by Bayesian approach as basis for the guava breeding program.

There are no guava cultivars resistant to the Meloidogyne enterolobii; for this reason, genetic breeding has been performed by introgressing genes into the current cultivars through interspecific hybridization. We used 33 microsatellite markers for the genetic-molecular characterization of segregating populations of Psidium resistant to M. enterolobii, aiming at selection within and between populations for generation advancement in the guava breeding program. The average number of alleles per locus ranged from 1.60 to 2.09. Populations 1 (P. guineense × P. cattleyanum) and 5 (P. guajava × P. cattleyanum) obtained the greatest genetic diversity, which can be confirmed by the higher observed-heterozygosity values (0.422 and 0.312, respectively). Bayesian analysis showed that the populations were subdivided into three groups, agreeing with the number of groups observed by Nei's genetic distance. The population obtained from the P. guineense × P. cattleyanum cross differed from the others with a clear structuring, whereas the P. guajava × P. cattleyanum and P. cattleyanum × P. guineense populations were the most similar between each other. The SSR markers were efficient in discriminating the populations, and individual 80 may be employed in future crosses with guava, allowing generation advancement in the guava breeding program aimed at resistance to M. enterolobii.

Individual selection of the first backcross generation of passion fruit potentially resistant to the fruit woodiness disease.

The REML/BLUP procedure has been successfully used for genetic progress through individual selection of high-yielding passion fruit genotypes resistant to the Cowpea aphid-borne mosaic virus. This study was thus developed to estimate genetic parameters and predict the gain obtained from individual selection of genotypes in a population derived from backcrosses in passion fruit. The experiment was set up as a randomized block design with four replicates, involving five full-sib families (genotypes from the first backcross). Variance components and the genetic values were estimated for eight agronomic traits via the REML/BLUP procedure. For all traits, genotypic variance between the genotypes from the first backcross showed little contribution to the phenotypic variance. The low heritability estimates obtained for the traits are overcome via individual BLUP estimates. Therefore, it was possible to obtain considerable gains with individual selection for the variables fruit length, average fruit weight, and pulp weight (19.50 to 14.04%; 22.93 to 17.97%; and 10.08 to 7.95%, respectively). For the traits showing lower gains, it is possible to obtain gains indirectly by selecting genotypes for correlated traits. Because this population derives from the first backcross generation, agronomic traits still must be recovered.

Morpho-agronomic characterization and analysis of genetic divergenceamong accessions of tomatoes (Solanum lycopersicum L.) / Caracterização morfo-agronômica e análise da diversidade genética entre acessos de tomates (Solanum lycopersicum L.)

ABSTRACT: The collection and characterization of tomato germplasm are of relevant importance for agriculture. This study aimed to collect and characterize, by way of morphological description and statistical tools for the composition of groups, tomato accesses from the Southern and Serrana regions of the State of Espírito Santo, as well as to establish the tomato germplasm bank of the Ifes - Campus de Alegre. Thirty-seven accessions were collected from different commercial locations of Espírito Santo. The experiment was conducted in the Ifes Campus de Alegre in the Agroecology sector. For the morpho-agronomic characterization, sixteen essential descriptors were used, nine quantitative and seven qualitative. In the color of the ripe fruit, there was the formation of five distinct groups with the colors yellow, green, orange, pink and red. In the format of the fruit, three groups were formed, slightly flattened, flattened and rounded. The ANOVA showed that there was a significant difference for all the quantitative characteristics evaluated. According to the Ward-MLM procedure, due to the high likelihood function in group seven (from 130.71), it was possible to group the 37 genotypes into seven groups. The greatest dissimilarity was observed in groups V and VII with a distance of 330.02, and the least dissimilar ones, groups IV and VI, with 8.21. Genetic variability was detected in tomato germplasm for the morpho-agronomic characteristics. Many of the accessions are promising sources of phenotypes of interest to the Ifes germplasm bank.

RESUMO: A coleta e caracterização do germoplasma de tomate são de relevante importância para a agricultura. O presente trabalho objetivou coletar e caracterizar, por intermédio de descritores morfoagronômicos e ferramentas estatísticas, os acessos de tomate das regiões Sul e Serrana do Estado do Espírito Santo, bem como constituir o banco de germoplasma de tomate do Ifes, Campus de Alegre. Foram coletados 37 acessos de tomate em diferentes pontos comerciais do Espírito Santo. O experimento foi conduzido no Setor de Olericultura do Ifes Campus de Alegre. Para a caracterização morfoagronômica, foram utilizados 16 descritores essenciais, 9 quantitativos e 7 qualitativos. Para a característica cor do fruto maduro, houve a formação de cinco distintos grupos com as cores amarelo, verde, laranja, rosa e vermelha. No formato do fruto, houve formação de três grupos, ligeiramente achatado, achatado e arredondados. A ANOVA mostrou que houve diferença significativa para todas as características quantitativas avaliadas. Pelo procedimento Ward-MLM, devido a elevada função de verossimilhança no grupo sete (de 130.71), foi possível agrupar os 37 genótipos em sete grupos. A maior dissimilaridade foi observada nos grupos V e VII com distância de 330.02, e os menos dissimilares, os grupos IV e VI, com 8.21. Detectou-se variabilidade genética no germoplasma de tomate para as características morfo-agronômicas. Muitos dos acessos são promissoras fontes de fenótipos de interesse para o banco de germoplasma do Ifes.