Juliano Gomes Pádua

ISSR Markers as a Tool for the Assessment of Genetic Diversity in Passiflora

Genetic variation among sweet, purple, and yellow passion fruit accessions was assessed using inter-simple sequence repeat (ISSR) markers. Eighteen ISSR primers were used to evaluate 45 accessions. The number of polymorphic bands per primer varied from 4 to 22, with 12.4 bands per primer on average. Nei’s genetic distance between accessions ranged from 0.04 to 0.35. Clustering using the neighbor-joining method resulted in the formation of 11 major clusters. It was not possible to classify the accessions according to their geographic origin, showing that there is no structure in the gene bank. The overall mean Shannon–Weaver diversity index was 0.32, indicating good resolution of genetic diversity in passion fruit germplasm using ISSR markers. Our results indicate that ISSR can be useful for genetic diversity studies, to provide practical information for parental selection and to assist breeding and conservation strategies.

Polymorphism of Microsatellite Markers in Papaya (Carica papaya L.)

A set of 81 new microsatellite markers for Carica papaya L. previously identified by data mining using freely available sequence information from Genbank were tested for polymorphism using 30 germplasm accessions from the Papaya Germplasm Bank (PGM) at Embrapa Mandioca e Fruticultura Tropical (CNPMF) and 18 landraces. The data were used to estimate pairwise genetic distances between the genotypes. A neighbor-joining based dendrogram was used to define clusters and infer possible genetic structuring of the collection. Most microsatellites were polymorphic (73%), with an observed number of alleles per locus ranging from one to eleven. The levels of observed and expected heterozygosity for 51 polymorphic loci varied from 0.00 to 0.85 and from 0.08 to 0.82, averaging 0.19 and 0.59, respectively. Forty-four percent of microsatellites showed polymorphism information content (PIC) higher than 0.50. The compound microsatellites seem to be more informative than dinucleotide and trinucleotide repeats in average alleles per locus and PIC. Among dinucleotides, AG/TC or GA/CT repeat motifs exhibited more informativeness than TA/AT, GT/CA and TG/AC repeat motifs. The neighbor-joining analysis based on shared allele distance could differentiate all the papaya accessions and landraces as well as differences in their genetic structure. This set of markers will be useful for examining parentage, inbreeding and population structure in papaya.

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.

Germinação de sementes de Passiflora setacea e dormência induzida pelo armazenamento

). A germinacao foi conduzida em papel germitest embebido em agua. O teste de tetrazolio foi empregado para verificar a viabilidade das sementes apos os periodos de armazenamento. Foi possivel verificar que: (i) as sementes de P. setacea podem ser desidratadas ate atingir, aproximadamente 4,7% de agua (base umida) sem perda da capacidade de germinacao; (ii) o armazenamento de sementes com baixo teor de agua, a baixas temperaturas pode induzir a dormencia de sementes de P. setacea; (iii) a dormencia e superada pelo tratamento das sementes com acido giberelico, ate o quinto mes de armazenamento; (iv) as sementes conservadas sob temperaturas subzero apresentaram maior porcentagem de viabilidade em relacao as armazenadas a 4 °C. Diante destes resultados, pode-se concluir que sementes de P. setacea podem ser conservadas por ate 8 meses, sob baixas temperaturas, a -20 ou -196 °C, pois mantem os padroes minimos de viabilidade estabelecidos internacionalmente.Termos para indexacao: maracuja do mato, viabilidade, conservacao, acido giberelico.GERMINATION OF Passiflora s

Preliminary characterization of Psidium germplasm in different Brazilian ecogeographic regions

O objetivo deste trabalho foi caracterizar 119 acessos de goiabeira e 40 acessos de aracazeiro identificados em 35 ecorregioes brasileiras, de acordo com descritores da International Union for the Protection of New Varieties of Plants (UPOV). A maioria dos acessos de aracazeiro apresentou grandes espacos entre as nervuras da folha, enquanto os de goiabeira apresentaram espacos pequenos. Os frutos de aracazeiro foram classificados como pequenos, enquanto os de goiabeira apresentaram tamanho de medio a grande. A maioria dos acessos de aracazeiro (91%) apresentou cor branca para a polpa do fruto, enquanto 58% dos de goiabeira apresentaram cor de rosa-claro a rosa-escuro. As diferencas nos frutos entre Psidium selvagens e domesticados indicam que os frutos foram os mais alterados pela selecao artificial.