Maria Angélica Pereira de Carvalho Costa

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.

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.

Selection and use recommendation in hybrids of ornamental pineapple

The use of pineapples as ornamental plants has increased in the last years due to their beauty and originality, demanding the generation of new varieties. The objective of the present work was to study the genetic variability and type of use of hybrids as ornamental pineapples, besides evaluating the resistance of these hybrids to Fusarium wilt. Six progenies, FRF-22 X FRF-1387, FRF-1392 X FRF-32, Curaua Roxo X Ananas Tricolor, G-44 X FRF-1387, FRF-1392 X FRF-224 and FRF-1387 X FRF-224, were evaluated by eleven morphological descriptors, and five categories of use were taken into account: landscaping plants, cut flower, potted plants, minifruits and foliage. High variability within and between progenies was detected, which allowed the selection of 16 hybrids as cut flowers, 17 as landscaping plants, four as minifruits, two as potted plants and just three as foliage. Fourteen of them were recorded for more than one type of use. For resistance to the Fusarium, out of the 31 hybrids evaluated, 11 presented resistance, 17 were moderately resistant and three were susceptible.

In vitro regeneration and morphogenesis of somatic embryos of cassava

Este trabalho teve como objetivo estudar a embriogenese somatica e a regeneracao de plantas da variedade Cigana Preta a partir de apices caulinares e folhas imaturas obtidos de plantas cultivadas in vitro. Para a inducao de embrioes, os explantes foram cultivados em meio Murashige e Skoog (MS) suplementados com acido 2,4 diclorofenoxiacetico (2,4-D) ou 4-amino-3,5,6-trichloropicolinic acid (Picloram), ambos nas concentracoes 8,0 e 12 mg L-1. O desenvolvimento dos embrioes obtidos foi testado por dois meios de cultura com diferentes concentracoes de benzilaminopurina (BAP) (D1 ou D2). Embrioes em estagio cotiledonar foram incubados em meio de germinacao, constituido de sais e vitaminas do MS, 2,0 µM de sulfato de cobre, 2,4 g L-1 de Phytagel®, e 1,77 µM BAP. A maior frequencia de calos e numeros de embrioes por explantes foi obtida com 8,0 mg L-1 da auxina Picloram. As plantas regeneradas, oriundas do tratamento com Picloram apresentaram desenvolvimento normal e num periodo minimo de quatro semanas foram transferidas para meio de multiplicacao. Cortes histologicos de embrioes malformados, provenientes dos explantes foliares cultivados em 2,4-D revelaram que as estruturas cotiledonares tem origens independentes da formacao do meristema apical caulinar e nao houve formacao do meristema apical caulinar nos embrioes, sendo a maioria classificado como corneta. Este trabalho demonstrou que em mandioca o uso de diferentes auxinas proporciona diferentes condicoes para a formacao de embrioes somaticos e que a baixa conversao em plantas foi decorrente de anormalidades desses embrioes.

Viability of pollen grains of tetraploid banana

Obtaining banana tetraploid cultivars from triploid strains results in total or partial reestablishment of fertility, allowing the occurrence of some fruits with seeds, a feature that is undesirable from a marketing perspective. The objective of this study was to assess the viability of pollen of 12 banana tetraploid hybrids (AAAB) by means of in vitro germination and two histochemical tests (acetocarmine and 2,3,5-triphenyltetrazolium chloride). The pollen tube growth was evaluated by germinating grains in three culture media — M1: 0.03% Ca(NO3)∙4H2O, 0.02% Mg(SO4)∙7H2O, 0.01% KNO3, 0.01% H3BO3 and 15% sucrose; M2: 0.03% Ca(NO3)∙4H2O, 0.01% KNO3, 0.01% H3BO3 and 10% sucrose; and M3: 0.015% H3BO3, 0.045% Ca3(PO4)2 and 25% sucrose. The acetocarmine staining indicated high viability (above 80%), except for the genotypes YB42-17 and Caprichosa, which were 76 and 70%, respectively. However, the in vitro germination rate was lower than 50% for all the genotypes, except for the hybrids YB42-17 (M1) and YB42-47 (M1). The medium M1 provided the greatest germination percentage and pollen tube growth. Among the genotypes assessed, YB42-47 presented the highest germination rate (61.5%) and tube length (5.0 mm). On the other hand, the Vitoria cultivar had the lowest germination percentage (8.2%) in medium M1. Studies of meiosis can shed more light on the differences observed in the evaluated tetraploids, since meiotic irregularities can affect pollen viability.

Spatial distribution and associated flora of Alcantarea nahoumii, a vulnerable endemic species to rocky outcrops of the Serra da Jibóia, Bahia, Brazil

The objective of this study was to characterize the spatial distribution pattern at different altitude gradients as well as to investigate the flora associated with A. nahoumii, considered to be endemic and vulnerable. The study was carried out in Serra da Jibóia, Santa Teresinha, Bahia, Brazil. An inventory was conducted of young and adult A. nahoumii specimens along with taxonomic identification and quantification of the associated species. The cover percentage of A. nahoumii, rock slope, organic matter percentage and exposed rock percentage were calculated, as well as the following phytosociological parameters: absolute density, relative density, absolute frequency, relative frequency, and dominance of A. nahoumii. For the spatial distribution, three indices were tested (Morisita, McGuinnes and Payandech). Canonical correspondence analysis was also applied to test the association of the environmental variables with the species in the community. A total of 1,660 individuals were encountered and classified according to taxonomy in 17 families, 25 genera and 28 species. The spatial distribution pattern of the A. nahoumii population is aggregate. The results demonstrate that the population structure of A. nahoumii is stable, but events such as fires and extractive exploitation make the species vulnerable, along with the other species that inhabit the area.

Population variation and island effect in Melipona subnitida (Hymenoptera: Apidae)

We examined the head morphology of island and mainland populations of the stingless bee Melipona subnitida. We employed geometric morphometrics to test for differences in head morphology and analyzed 122 colonies. Head measurements were performed using 25 landmarks and semi-landmarks. For head shape, landmarks were analyzed by generalized procrustes analysis, principal component analysis (PCA), Mahalanobis distance, discriminant function analysis, cross-validation and unweighted pair-group method clustering (UPGMA). For head size, data were analyzed by analysis of variance (ANOVA), followed by the Tukey test. In addition, the relations between head shape, head size, geographical distance and altitude were analyzed using Pearson’s correlation coefficients. Morphological analyses revealed significant differences (p<.01) between mainland and island populations. Moreover, island bees differed in head shape and head size. The first two principal components explained 69.72% of the total variation, and UPGMA revealed that the individuals collected on the Island of Fernando de Noronha differed from the remaining locations, with 100% bootstrap support. Cross-validation correctly classified 84% of the individuals into their respective locations. The results also indicated structuring of those populations introduced to and isolated on the Island of Fernando de Noronha for more than 30 years. The characterization of the studied M. subnitida populations, especially the island populations, alerts us to the fact that isolation may lead to a loss of diversity, or even of the whole population, in M. subnitida and the remaining meliponines, possibly negatively affecting biotic interactions, especially plant–pollinator interactions. Variación poblacional y efecto insular en Melipona subnitida (Hymenoptera: Apidae) Examinamos la morfología de la cabeza de poblaciones insulares y continentales de Melipona subnitida. Empleamos morfometría geométrica para probar las diferencias en la morfología de la cabeza y analizamos 122 colonias. Las mediciones de la cabeza se realizaron utilizando 25 puntos y semi-puntos de referencia. Para la forma de la cabeza, los puntos de referencia se analizaron mediante el análisis procrustal generalizado, el análisis de componentes principales (PCA), la distancia Mahalanobis, el análisis de funciones discriminantes, la validación cruzada y la agrupación de métodos de grupos de pares no ponderados (UPGMA). Para el tamaño de la cabeza, los datos se analizaron mediante el análisis de varianza (ANOVA), seguido de la prueba de Tukey. Además, se analizaron las relaciones entre la forma de la cabeza, el tamaño de la cabeza, la distancia geográfica y la altitud utilizando los coeficientes de correlación de Pearson. Los análisis morfológicos revelaron diferencias significativas (p < 0,01) entre las poblaciones del continente y de las islas. Además, las abejas insulares diferían en la forma y el tamaño de la cabeza. Los dos primeros componentes principales explicaron el 69,72% de la variación total, y la UPGMA reveló que los individuos recolectados en la Isla de Fernando de Noronha difirieron del resto de las localidades, con un 100% de apoyo de bootstrap. La validación cruzada clasificó correctamente al 84% de los individuos en sus respectivas ubicaciones. Los resultados también indicaron la estructuración de las poblaciones introducidas y aisladas en la isla de Fernando de Noronha durante más de 30 años. La caracterización de las poblaciones estudiadas de M. subnitida, especialmente las poblaciones insulares, nos alerta de que el aislamiento puede llevar a una pérdida de diversidad, o incluso de toda la población, en M. subnitida y los meliponinos restantes, afectando posiblemente negativamente a las interacciones bióticas, especialmente las interacciones planta-polinizador.

Pollen types from colonies of Melipona scutellaris Latreille, 1811 (Hymenoptera: Apidae) established in a coffee plantation

Abstract Melipona scutellaris is a eusocial bee with potential to be used as a crop pollinator. This study aimed to identify pollen types used by Melipona scutellaris through the analysis of pollen loads and honey samples in colonies established in a coffee plantation. We analysed 117 pollen loads and pollen content of 15 honey samples. In the pollen loads, we identified 40 pollen types. Poincianella pyramidalis, Coffea arabica, Commelina villosa, Mimosa tenuiflora, Myrcia, Senna macranthera, Solanum and Syagrus coronata stood out as predominant pollen. We found a negative correlation between the abundances of the pollen types Coffea arabica and Mimosa tenuiflora during coffee flowering. In the honey samples, we recorded 33 pollen types. Eucalyptus and Machaerium occurred in frequencies of between 16 and 45%. Although Melipona scutellaris gathers resources from several plant species, its diet is based on a relatively narrow subset of plants.

Investigating the floral and reproductive biology of the endangered microendemic cactus Uebelmannia buiningii Donald (Minas Gerais, Brazil)

The Cactaceae are known to be amongst the most endangered plant families of the world due to reduction of their habitats and activities of collectors. As the species of the family are dependent on animals to perform cross pollination, and hence seed production, their population performance may be further negatively affected by interrupted biotic interactions. For efficient conservation of rare species, knowledge on reproductive biology and pollinators is of prime importance. In our study we focused on Uebelmannia buiningii Donald, a microendemic cactus from the Serra Negra State Park, Minas Gerais state, Brazil. During four field expeditions to three localities of the species between September 2012 and September 2013, we measured flowers, detected nectar-guides and osmophores and performed pollen viability tests. We studied the reproductive system of the species using manual self- and cross-pollination tests and observed pollinators. Our results revealed that the flowering period takes place during the dry season, between April and October, and that the diurnal flowers open between 7:00 a.m. and 5 p.m. The flowers are shortly tubular with yellow perianth-segments. We found neither nectar nor nectar-guides, and osmophores appeared as glands within the flower tube. Whereas pollen viability was 90.25%, manual cross-pollination tests have shown cross-pollination with gametophytic incompatibility. We observed two bee species visiting the flowers and acting as effective pollinators: Dialictus opacus and Plebeia sp. The combination of low reproductive activity with gametophytic incompatibility, together with the reduced number of individuals in a population and low number of populations, makes the endemic cactus U. buiningii a critically endangered species.