Onildo Nunes de Jesus

Genetic Breeding and Diversity of the Genus Passiflora: Progress and Perspectives in Molecular and Genetic Studies

Despite the ecological and economic importance of passion fruit (Passiflora spp.), molecular markers have only recently been utilized in genetic studies of this genus. In addition, both basic genetic researches related to population studies and pre-breeding programs of passion fruit remain scarce for most Passiflora species. Considering the number of Passiflora species and the increasing use of these species as a resource for ornamental, medicinal, and food purposes, the aims of this review are the following: (i) to present the current condition of the passion fruit crop; (ii) to quantify the applications and effects of using molecular markers in studies of Passiflora; (iii) to present the contributions of genetic engineering for passion fruit culture; and (iv) to discuss the progress and perspectives of this research. Thus, the present review aims to summarize and discuss the relationship between historical and current progress on the culture, breeding, and molecular genetics of passion fruit.

Suscetibilidade à queda natural e caracterização dos frutos de diversos genótipos de bananeiras

Natural fruit dropping of ripe bananas in result of individual separation of fruits from the hand crown, is called finger drop, this characteristic is undesirable and would limit the marketing of new cultivars. Fruits that stand out in the hand have a reduced shelf life, and do not present a pleasant appearance for customers. This study was carried out in order to quantify the susceptibility to natural fruit dropping in fruits from different genomic groups and ploidies, and to identify correlations between natural dropping and various physical fruit characteristics. Diploid, triploid e tetraploid banana plants from several genomic groups were used, altogether 37 genotypes. The physical characteristics were used in a variance analysis and the results compared with the Scott-Knott test. Results proved the high resistance against dropping among genotypes that belong to the genomic group BB (Butuhan, Pirai and BB Franca), Terra (AAB), Poteau Nain (fig type) (ABB) and Thap Maeo (AAB), while Prata-Ana (AAB), Grande Naine (AAA), Ambrosia (AAAA), Ouro (AA) and FHIA 18 (AAAB) presented intermediate values of dropping resistance. Among banana plants with low resistence, the improved hybrids Pioneira (AAAB), YB42-21 (AAAB), Buccaneer (AAAA) and Calypso (AAAA) and the cultivar Ouro da Mata (AAAB) were outstanding. A higher positive correlation between fruit firmness and resistance toward finger drop could be verified. The study of genotype and ploid groups indicated a greater resistance against dropping among banana plants belonging to the BB group and ABB and AAB triploid genotypes.

Severidade de doenças em maracujazeiro para identificação de fontes de resistência em condições de campo

O objetivo deste trabalho foi utilizar uma escala de severidade para algumas doencas do maracujazeiro, visando a identificacao de fontes de resistencia. Foram avaliados 75 acessos de Passiflora spp. em condicoes de campo, sob alta infeccao natural dos patogenos, para a severidade da virose, nas folhas (VIFO), frutos (VIFR) e distribuicao na planta (VIPL), bem como para verrugose nos frutos e ramos (VEFR e VERA, respectivamente) e antracnose nos frutos (ANFR). Houve alta variabilidade para resistencia as doencas, embora poucos acessos tenham sido classificados como resistentes a VIFO, VIFR e VIPL, sendo que apenas um acesso de P. setacea (BGM237) foi considerado resistente aos tres tipos de avaliacoes para virose. A maioria dos acessos de maracujazeiro- amarelo e roxo possui algum grau de suscetibilidade a um ou outro sintoma da virose. Quanto a VERA, acessos de P. alata e P. cincinnata foram mais resistentes, embora P. alata demonstre maior resistencia a VEFR. Alguns acessos de P. edulis comportam-se como moderadamente resistente a VERA e VEFR. A maioria dos acessos de P. alata, P. cincinnata e P. setacea nao apresentou sintomas de antracnose nos frutos. A escala de severidade adotada mostrou-se eficiente para a separacao dos acessos de maracujazeiro em diferentes classes de resistencia a doencas.

Potential of SNP markers for the characterization of Brazilian cassava germplasm

Key messageHigh-throughput markers, such as SNPs, along with different methodologies were used to evaluate the applicability of the Bayesian approach and the multivariate analysis in structuring the genetic diversity in cassavas.AbstractThe objective of the present work was to evaluate the diversity and genetic structure of the largest cassava germplasm bank in Brazil. Complementary methodological approaches such as discriminant analysis of principal components (DAPC), Bayesian analysis and molecular analysis of variance (AMOVA) were used to understand the structure and diversity of 1,280 accessions genotyped using 402 single nucleotide polymorphism markers. The genetic diversity (0.327) and the average observed heterozygosity (0.322) were high considering the bi-allelic markers. In terms of population, the presence of a complex genetic structure was observed indicating the formation of 30 clusters by DAPC and 34 clusters by Bayesian analysis. Both methodologies presented difficulties and controversies in terms of the allocation of some accessions to specific clusters. However, the clusters suggested by the DAPC analysis seemed to be more consistent for presenting higher probability of allocation of the accessions within the clusters. Prior information related to breeding patterns and geographic origins of the accessions were not sufficient for providing clear differentiation between the clusters according to the AMOVA analysis. In contrast, the FST was maximized when considering the clusters suggested by the Bayesian and DAPC analyses. The high frequency of germplasm exchange between producers and the subsequent alteration of the name of the same material may be one of the causes of the low association between genetic diversity and geographic origin. The results of this study may benefit cassava germplasm conservation programs, and contribute to the maximization of genetic gains in breeding programs.

Identification of passion fruit genotypes resistant to Fusarium oxysporum f. sp. passiflorae

This study aimed to characterize the resistance of 31 passion fruit (Passiflora sp.) genotypes to Fusarium oxysporum f. sp. passiflorae (FOP). About 20 seedlings of each genotype were inoculated by immersing the roots in a suspension of 106 macroconidia mL-1 for five minutes and then transplanting them into pots containing a mixture of soil and sterile substrate. They were evaluated daily for 120 days for the occurrence of wilt symptoms and death. These data were used to calculate the area under the disease progress curve, for survival analysis and grouping. The mortality rate ranged from 0 to 100% and the AUDPC ranged from 0 for genotypes without symptoms of the disease to 6,650.63 for the hybrid HFOP-01. Genotypes were classified into four subgroups: resistant, moderately resistant, susceptible and highly susceptible. The resistance was genotype dependent, but no significant variation was found between the purple and the yellow P. edulis.

Caracteres da planta e do cacho de genótipos de bananeira, em quatro ciclos de produção, em Belmonte, Bahia

Fifteen genotypes of banana were evaluated for their performance in the Mata Atlântica ecosystem, at Belmonte city, BA, with no irrigation system. The genotypes, including varieties and hybrids from Embrapa Mandioca e Fruticultura Banana Breeding Program, were as follow: Mysore, Thap Maeo, Caipira, Nam, PV03-76, PV03-44, JV03-15, PA03-22, Pioneira, Prata Ana, Ouro da Mata, Prata, Pacovan, Maca and Grande Naine. The agronomic traits evaluated in the experiments were: plant height (cm) and diameter of pseudostem (measure at 30 cm above ground) during flowering; number of days from planting to harvest, weight of bunch (kg), number of hands and fingers to bunch and fingers length (cm). The plant spacing was 3,0 m between rows and 2,0 m in the row. Randomized block was used as the experimental design. Each experimental unit consisted of 25 plants, with three replications. Culture conditions followed the standard procedure for the crop. No chemical control of yellow Sigatoca was used. The analysis of the data showed that, based on the parameters evaluated in the experiments, the identification of promising varieties and cultivars could be identified for further recommendation to the growers. Among the selected genotypes, Thap Maeo, Mysore, Caipira, Nam and PV03-76 showed the best results.

New Microsatellite Markers for Wild and Commercial Species of Passiflora (Passifloraceae) and Cross-Amplification

Premise of the study: We developed the first microsatellites for Passiflora setacea and characterized new sets of markers for P. edulis and P. cincinnata, enabling further genetic diversity studies to support the conservation and breeding of passion fruit species. Methods and Results: We developed 69 microsatellite markers and, in conjunction with assessments of cross-amplification using primers available from the literature, present 43 new polymorphic microsatellite loci for three species of Passiflora. The mean number of alleles per locus was 3.1, and the mean values of the expected and observed levels of heterozygosity were 0.406 and 0.322, respectively. Conclusions: These microsatellite markers will be valuable tools for investigating the genetic diversity and population structure of wild and commercial species of passion fruit (Passiflora spp.) and may be useful for developing conservation and improvement strategies by contributing to the understanding of the mating system and hybridization within the genus.

Molecular fingerprinting of Fusarium oxysporum f. sp. passiflorae isolates using AFLP markers

Fusarium oxysporum f. sp. passiflorae W.L. Gordon (FOP) is one of the most important fungal pathogens of passion fruits. Understanding molecular variation of isolates from different areas is of utmost importance. Molecular fingerprinting on 14 isolates of FOP were conducted using AFLP molecular markers (Amplified Fragment Length Polymorphism), and their genetic variability were estimated. Twenty-five AFLP primer combinations were selected for amplification of FOP isolates and one for Fusarium oxysporum f. sp. cubense W.C. Snyder & H.N. Hansen (FOC), resulting in 99% polymorphic fragments, with an average of 40 fragments per primer combination. Specific fingerprints could be generated for most of the isolates evaluated; we observed a high power of discrimination of the AFLP primer combinations, with the presence/absence of up to 26 specific fragments per isolate. Thus, specific fingerprinting was obtained for 10 of the 15 isolates analyzed. The values of the polymorphic information content, the index and the resolving power of the markers showed wide variation and reflected the high informative contents of the primers used in the characterization of the FOP isolates. The FOP isolates were divided into four groups, irrespective of their geographic origins, with the allocation of 5, 7, 1 and 1 FOP isolates into Groups II, III, IV and V, respectively. A wide genetic diversity was observed in FOP isolates, which should be taken into consideration when implementing strategies for the improvement of passion fruit in the search for cultivars with multiple resistance to different isolates.

AMMI analysis of the adaptability and yield stability of yellow passion fruit varieties

High yield stability and adaptability of yellow passion fruit varieties (Passiflora edulis Sims. f. flavicarpa Deg.) are highly desirable attributes when exploring different environments. This study aimed to evaluate the adaptability and yield stability of yellow passion fruit varieties using AMMI (additive main effects and multiplicative interaction) and other ancillary statistics. Twelve varieties were evaluated in eight environments. Analysis of variance showed effects attributable to the varieties (G), environment (E) and their interaction (G × E). The first two multiplicative components of the interaction accounted for 69% of the sum of squares. The scores of the principal interaction components showed high variability for the environments relative to the variety effects. High varietal phenotypic stability was observed in three environments; which can be used in yellow passion fruit breeding programs for initial selection trials. A biplot-AMMI analysis and yield stability index incorporating the AMMI stability value and yield capacity in a single non-parametric index were useful for discriminating genotypes with superior and stable fruit yield. AMMI analysis also allowed for the identification of more productive varieties in specific environments, leading to significant increase in passion fruit productivity.

Cross-species amplification of microsatellite loci developed for Passiflora edulis Sims. in related Passiflora Species

The aim of this study was to evaluate the selected 41 SSR markers developed for yellow passion fruit (Passiflora edulis f. flavicarpa Sims.) for their transferability to 11 different Passiflora species. Twenty-one SSR were successfully amplified in 10 wild species of passion fruit producing 101 bands. All the markers were amplifiable for at least one species. The mean transferability was 68,8%, ranging from 15,4% (primer PE11) to 100 % (PE13, PE18, PE37, PE41 and PE88). Transferability was higher for the species from the Passiflora subgenus than for those from the Decaloba and Dysosmia subgenus. The results indicated a high level of nucleotide sequence conservation of the primer regions in the species evaluated, and consequently, they could potentially be used for the establishment of molecular strategies for use in passion fruit breeding and genetics.