Janay Almeida dos Santos-Serejo

Genetic diversity of carotenoid-rich bananas evaluated by Diversity Arrays Technology (DArT)

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.

Agronomic and molecular characterization of diploid improved banana genotypes.

An investigation about the genetical diversity among eleven banana diploid genotypes using nine agronomical characteristics and sixteen microsatellite markers was implanted at Embrapa Cassava and Tropical Fruits, Cruz das Almas (BA), Brazil. The generalized distance of Mahalanobis indicated the presence of genetic diversity. The genotypes were grouped into tree clusters. Among the investigated characteristics, the plant height, number of bunchs, number of fruits per bunch and pseudostem exhibited high contribution towards genetic divergence. The average number of alleles per primer was 7.51, with a total of 120 alleles identified. The average similarity among the all diploid was 0.44, range from 0.29 up to 0.60. New parental combinations can be identified with base of the divergence between these diploids, contributing for development of new improved diploids preventing the narrow genetic base and creating new genetic variability for selection.

Variabilidade genética estimada entre diplóides de banana por meio de marcadores microssatélites

O objetivo deste trabalho foi estimar a divergencia genetica entre 38 diploides de banana do programa de melhoramento da Embrapa Mandioca e Fruticultura Tropical, incluindo genotipos melhorados, cultivados e selvagens, por meio de 15 marcadores microssatelites ou SSR. As similaridades geneticas, com base no coeficiente de Jaccard, foram utilizadas para fazer o agrupamento dos genotipos pelo metodo UPGMA. O numero de alelos obtidos foi 113, com media de 7,53 alelos por iniciador. A similaridade genetica media foi de 0,22, e variou de 0,028 a 0,48, o que indica existencia de variabilidade genetica entre os genotipos. A analise de grupos, com base no polimorfismo de microssatelites, nao pode separar completamente os hibridos melhorados, cultivados e selvagens. Alguns diploides agruparam-se com base em sua origem geografica, entre eles Musa ornata e IAC-1, e Tjau Lagada e Lidi, enquanto que, em outros, nenhuma relacao foi estabelecida. Houve tendencia de agrupamento entre os diploides aparentados, como: SH3263 e 8694-20, 4279-01 e 9179-03, 1304-06 e 5854-03, 86B79-10 e 7341-03, 86B79-12 e 0337-02, e 9194-04 e 4154-08.

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.

Melhoramento genético da bananeira: estratégias e tecnologias disponíveis

Bananas are cultivated in more than 107 countries in an area of 4.1 million hectares with a production of 95 million tons and considered the second most produced fruit worldwide. Bananas are attacked by viruses (CMV and BSV), fungi (Yellow and Black Sigatoka and Fusarium), bacteria (Moko), nematodes and insects (Weevils). However, through genetic breeding, it is possible to achieve resistance to most pests and diseases. The center of origin of most of Musa spp. germplasm is the Asian Continent, where diploid, triploid, Tetraploid with genome Musa acuminata and Musa balbisiana bananas are found. In banana breeding, especially for disease resistance, the following methods are employed: introduction and selection of clones; hybridization (crosses between diploids and diploids, triploids and diploids and diploids with tetraploids); chromosome duplication; mutation and transgenic. Methods involving hybridization, however, the method mostly used, is limited by pathernocarpy, sterility, variable number of ploidy levels and low seed production. All varieties produced by the program are then evaluated in banana producing regions in Brazil. Recently new breeding techniques based on genetic information on Musa ssp. are being incremented.

In vitro pollen germination and pollen viability in passion fruit (Passiflora spp.)

O uso de Passifloras como plantas ornamentais e recente, e por isso pouco se sabe sobre a possibilidade de cruzamento entre diferentes especies, bem como sobre a viabilidade polinica. O objetivo do trabalho foi avaliar a viabilidade do polen de seis especies de maracujazeiro coletados em diferentes estadios de desenvolvimento fisiologico por meio da germinacao in vitro, bem como via analise histoquimica, por meio do uso de corantes. O polen foi coletado em tres estadios (pre-antese, antese e pos-antese). Foram comparadas tres composicoes de meios de cultura para avaliar a germinacao in vitro, e para a analise histoquimica utilizou-se de dois corantes o 2,3,5-cloreto de trifeniltetrazolio (TTC) e o lugol. O meio de cultura contendo 0,03% de Ca(NO3).4H2O, 0,02% de Mg(SO4).7H2O, 0,01% de KNO3, 0,01% de H3BO3, 15% de sacarose, solidificado com 0,8% de agar e pH ajustado para 7,0, proporcionou maior percentual de graos de polen germinados. O melhor momento de coleta do polen com relacao a melhor viabilidade e a germinacao e na antese. O corante TTC e o lugol superestimaram a viabilidade de polen, ja que todos os acessos apresentaram indice de viabilidade alto, quando comparados aos resultados obtidos in vitro.

Morphology and viability of pollen grains from passion fruit species (Passiflora spp.)

The characterization and viability of pollen grains are useful tools to guide crosses in breeding programs. The objective of this study was to describe the morphological patterns and viability of pollen grains from five accessions of Passiflora edulis f. flavicarpa O. Deg. and five accessions of Passiflora setacea DC. Pollen morphology descriptions were made using light microscopy and scanning electron microscopy, whereas the viability analysis was performed by in vitro germination and histochemical analysis (Lugols solution and 2,3,5-triphenyltetrazolium chloride). Pollen grains assessed for germination were inoculated in culture medium containing Ca(NO3).4H2O (0.03%), Mg(SO4).7H2O (0.02%), KNO3 (0.01%), H3BO3 (0.01%), sucrose (15%) and agar (0.8%). Although P. edulis and P. setacea showed the same shape and type of pollen aperture, the two differed in terms of their morphology and exine ornamentation pattern. In vitro analysis showed that one of the P. edulis f. flavicarpa accessions (designated BGP 330) presented the highest germination rate (53.98%) and longest pollen tube (2.18 mm). The histochemical analysis overestimated pollen viability when compared with the in vitro results. The results of this study contribute to the breeding of Passiflora species by increasing the understanding of their morphology and pollen grain viability.

Genetic variability of banana with ornamental potential

The Musa germplasm collection at Embrapa Cassava and Fruits detains accessions from different sections of the Musa genus. The objective of the present study was to identify and morphologically characterize banana accessions from the banana germplasm with ornamental potential, as well as to quantify their genetic variability; and identify possible progenitors to be used in breeding aiming to achieve ornamental crossbreeds. The accessions were evaluated with the use of 32 morphological descriptors. Then, they were the following grouped into categories: landscape plants, cut flower, potted plants, and male inflorescence minifruits. The pre-selected accessions presented great genetic variability and ornamental potential for different uses. The accessions of the Rhodochlamys and Callimusa sections were selected to be used as landscape plants, cut flowers, potted plants, male inflorescence and minifruits. Most of the diploids from the Eumusa section evaluated in this study are indicated for the production of ornamental minifruits, except for ‘Lidi’ and Cici, which can also be indicated as landscape plants. The BB diploids have great potential for the use of the male inflorescence in floral arrangements, and did not offer any other indication.

Somatic embryogenesis, cell suspension, and genetic stability of banana cultivars

The induction of somatic embryogenesis in banana is extremely difficult because of endogenous problems of the species and genotype dependency. Establishing a suitable protocol for somatic embryogenesis is necessary for applying biotechnological approaches to assist the genetic improvement, by facilitating the access to individual cells or groups of cells for use in genetic transformation, and the induction of polyploidy and mutagenesis. Embryogenic cultures were induced from immature male flowers of two important cultivars of banana, ‘Grand Naine’ (AAA) and ‘Tropical’ (AAAB), using immature male flowers. Cell suspensions were established, and regenerated plants were evaluated for their genetic stability using 11 simple sequence repeat markers. For induction of embryogenesis, different doses of autoclaved glutamine in the induction medium were used, and somatic embryos were converted into plants in medium supplemented with benzylaminopurine and naphthalene-1-acetic acid. ‘Grand Naine’ formed somatic embryos in glutamine-free media, while ‘Tropical’ somatic embryos grew in the presence of autoclaved glutamine. During regeneration, ‘Grand Naine’ showed better results for formation of embryos in culture medium without growth regulators, but these embryos were not converted into plants when kept in the same medium, while ‘Tropical’ produced a large number of plants regenerated when kept in the same medium. The simple sequence repeat markers used did not detect any genetic variation. These results suggest that the establishment of embryogenic cell suspension cultures of banana may be effective for production of genetically stable plants on a large scale as well as being a biotechnological tool to support banana genetic improvement.

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.