Mailson Monteiro do Rêgo

A low-cost alternative membrane system that promotes growth in nodal cultures of Brazilian ginseng [ Pfaffia glomerata (Spreng.) Pedersen]

In vitro propagated plants under conditions of low gas exchange generally show morphological and physiological anomalies that lead to high mortality rates during ex vitro acclimatization. The use of gas-permeable membranes increases natural ventilation in culture vessels, photosynthesis and growth rates. However, commercial membranes are expensive, which limits their application. In this study, low-cost, simple to manufacture, alternative membranes were developed to promote gas exchange in jars used for in vitro plant tissue culture. The membranes were developed using polytetrafluoroethylene film and two or three layers of microporous tape (Missner & Missner®), and were designed to increase the growth of nodal cultures of Pfaffia glomerata (Brazilian ginseng). Conditions that provided higher gas exchange led to an increase in plant growth and content of photosynthetic pigments compared to a closed system without a gas-permeable membrane. The alternative membranes showed similar results for water vapor loss rate and photosynthetic pigments when compared to a commercial membrane. The alternative membranes were also an efficient barrier against contamination and remained intact after being autoclaved multiple times. Among the membranes tested, the traits of the P. glomerata in vitro-derived plants were similar when propagated using the alternative membrane with three layers of microporous tape or the commercial membrane. However, the alternative membrane has a unit cost that is ten times lower than the commercial membrane.

Testing methods for producing self-pollinated fruits in ornamental peppers

The pepper market in Brazil is experiencing major changes. There is a mounting interest in new types of peppers, including those of ornamental relevance. The use of protected cultivation is raising the demand for high-yielding hybrids, with higher commercial value, so as to turn this production system into a profitable investment. Hybrid seeds are obtained by crossing endogamic lines, which, in their turn, result from successive self-pollinations. The objective of this study was to compare two methods of protecting selfed flower buds from contamination with exogenous pollen in ornamental peppers. The experiment was carried out in a greenhouse, on a laboratory of the Universidade Federal da Paraiba. We took plants of 15 hybrids and their reciprocals to test two methods to protect selfed flower buds: 1= bud covering with aluminum foil; and 2= bud sealing with white glue. We carried out ten self-pollinations per hybrid, in pre-anthesis, for each method. We evaluated the average fruit set rate per method within each hybrid. The general fruit setting average in method 1 (16%) was lower than in method 2 (51%); with not a single hybrid in which fruit set rate of method 1 has exceeded that of method 2. A few hybrids showed up to 90% fruit set after self-pollination when flower buds were sealed with white glue (method 2), in contrast to a maximum of 40% fruit set when using method 1. The direction of the cross, direct or reciprocal, also affected fruit set rate, causing either reduction or increase, but with no effects of the selfed bud protecting method. Considering our results, we indicate the use of white glue to seal selfed flower buds to secure the success of controlled selfing in pepper.

Morphological and chemical characterization of fruits of Capsicum spp. accessions

This study aimed to evaluate 69 Capsicum accessions from the Germplasm Bank of Universidade Federal de Roraima, for some fruit quality traits. The experiment was performed in a completely random design, with 69 treatments and 3 replications. The 69 accessions were evaluated for fourteen quantitative and two qualitative traits of ripe fruits. Quantitative fruits data were subjected to an analysis of variance, and the means were grouped by Scott-Knott test (p≤0.01). All characteristics had significant effect of treatments (p <0.01) for all evaluated traits. The data showed high genetic variability to future use in a Capsicum breeding program. The accessions 33, 44 and 41 showed major values for dry matter content and total soluble solids; these should be used to improve these traits in a paprika breeding program. On the other hand, the accession 48 showed major values for fresh weight, major fruit length and fruit width. The accession 33, belonging to the Capsicum frutescens species, with high vitamin C content should be used in a fresh market Capsicum breeding program.

Variabilidade em população base de pimenteiras ornamentais (Capsicum annuum L.)

O objetivo deste trabalho foi caracterizar progenies de uma populacao base de pimenteiras (Capsicum annuum L.). Foram utilizadas 54 plantas de uma geracao F2 de pimenteiras ornamentais, para se avaliarem os seguintes caracteres morfoagronomicos: altura da planta (AP), diâmetro da copa (DDC), altura da primeira bifurcacao (APB), diâmetro do caule (DCL), comprimento da folha (CFL), largura da folha (LFL), comprimento da corola (CDC), comprimento de antera (CANT), comprimento do estilete (CES) e largura da petala (LAP). O delineamento experimental foi inteiramente casualizado, com tres repeticoes. Os dados foram submetidos a Analise de Variância, com posterior agrupamento das medias para o teste de Scott-Knott (p<0,01). Com excecao do CANT, verificaram-se diferencas significativas para os demais descritores, pelo Teste F. O DCL foi o descritor com maior herdabilidade (99,49%), seguido de DDC (96,14%) e APB (94,05%). O caractere DCL apresentou maior variabilidade entre as plantas, formando 13 classes, seguido de DDC, com oito e APB, com seis classes. Quando se utilizaram as tecnicas multivariadas, foi possivel agrupar as 54 plantas em oito grupos, sendo o grupo 1 o que reuniu maior numero de plantas (35). A caracteristica que mais contribuiu para a divergencia genetica foi o diâmetro do caule (68,97%), seguida pelo diâmetro da copa (9,22%), altura da primeira bifurcacao (6,76%) e altura da planta (4,58%). Ja as caracteristicas de flor foram as que menos contribuiram para a variabilidade (10,47%). Houve variabilidade entre as plantas estudadas, sendo possivel praticar selecao dentro dessa familia, dando continuidade ao Programa de Melhoramento de Pimenteiras.

Suppression of ethylene levels promotes morphogenesis in pepper ( Capsicum annuum L.)

Ethylene and polyamines (PAs) are two phytohormones that play important roles during in vitro morphogenesis of several plant species. The interaction between ethylene and PAs has been of interest because both have S-adenosylmethionine as a precursor. To study the influence of ethylene and PAs on in vitro morphogenesis of an ornamental pepper, we added an ethylene scavenger, PAs, a PA inhibitor, and compounds that affect ethylene biosynthesis and activity to the regeneration medium. Regeneration frequencies increased in response to treatment with ethylene inhibitors (aminoethoxyvinylglycine and silver thiosulfate) and an ethylene scavenger (mercury perchlorate). Treatment with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid reduced the regeneration frequency, increased callus formation, and increased ethylene levels; similar results were obtained in response to treatment with the PA inhibitor methylglyoxal-bis(guanylhydrazone). By contrast, treatment with PAs (particularly spermidine and spermine) decreased ethylene levels, increased the regeneration frequency, and increased shoot bud formation. These results suggest a coordinated regulation of ethylene and polyamines because the suppression of ethylene levels using ethylene inhibitors, polyamines, or mercury perchlorate increased the in vitro regeneration frequency and morphogenic responses of Capsicum annuum L.

Estabelecimento in vitro e micropropagação de maracujá silvestre (Passiflora foetida L.)

Among the species of the genus Passiflora, P. foetida L. presents highest genetic variability and also great medicinal importance. This species is used in the treatment of diseases such as asthma, jaundice, and in the form of poultices for erysipelas and skin diseases with inflammation. Therefore, studies are needed to preserve them. Its seeds present dormancy and often take several months to germinate. The tissue culture is a alternative form to propagate species. The objective was to establish and micropropagation P. foetida L., and create a germplasm bank. Seeds were scarified, disinfected, and inoculated on MS medium (½) without regulators for 66 days. Hypocotyls explants obtained of seedlings in vitro germinated were transferred and placed in the same medium supplemented with BAP (1,0 mg L-1). In the establishment phase of 45% of the explants sprouted and formed axillary buds. 88,9% of hypocotyl explants induced shoots and 11,1% produced callus. Seedling measuring 1,82 cm length and rooted were acclimatized.

Production and Breeding of Chilli Peppers (Capsicum spp.)

The book contains aspects of production, genetics and breeding of Capsicum species with emphasis on fruit quality, yield and its nutritional characteristics among with some specific chapters focusing on breeding and physiological features of potted ornamental Chili and responses to abiotic stress and postharvest of fruits

Synchronizing the in vitro germination of Psidium guineense Sw. seeds by means of osmotic priming.

The Brazilian guava (Psidium guineense Swartz) is seed-propagated and, being native to the Caatinga biome, may frequently have uneven germination.Thus, we aimed to evaluate the synchronization of the in vitro seed germination of three accessions of the Brazilian guava, using water, polyethyleneglycol (PEG 6000), and potassium nitrate (KNO3) at different potentials and times of osmotic priming. Seeds from three accessions of the Brazilian guava (Y85, Y93,and Y97) from the UNEB/BA Germplasm Active Bank were subjected to the following pretreatments: -0.6, -1.0, -1.4, and -1,8 MPa PEG 6000; 10 and 20% KNO3 for 24h; 10 and 20% KNO3 for 48h; water for 24 and 48h; and non-primed seeds as the control. The experimental design was therefore a 10x3+1 factorial scheme. We assessed the germination percentage (G), mean germination time (MGT), germination speed (GS), and germination speed index (GSI). Data was subjected to analysis of variance followed by a means test (Duncan at 5% probability) and regression. There was interaction between the priming treatments and accessions for all evaluated features, except G. PEG 6000 decreased the MGT (from 6 to 8 days) and increased GS and GSI of seeds from all three accessions at potentials -1.0 to -1.5 MPa.Water-priming had a positive effect on MGT, GS, and GSI of accession Y85 seeds. KNO3 negatively affected germination of seeds from all three accessions. Thereby, we could synchronize seed germination of accessions Y85 and Y97 with PEG 6000.

Tissue Culture of Capsicum spp.

Plant tissue culture comprises a set of in vitro techniques, methods, and strategies that are part of plant biotechnology. In this chapter, we discuss some difficulties and recent advances in the in vitro culture of peppers, aiming at the breeding of cultured species belonging to the genus. It also reports our experience and contribution to the induction of androgenic haploid embryos, sensitivity and resistance to ethylene, flowering, fruiting and seed production in vitro, as well as embryo rescue and their utilization in the breeding program of ornamental pepper from Brazil.

Correlation between morphoagronomic traits and resistance to ethylene action in ornamental peppers.

The post-production quality of ornamental peppers can be shorted due to exposure to ethylene. The concentration of this phytohormone at 10 µL/L induces leaf, fruit and flowers abscission, ripening of climacteric fruits, organ senescence, seed germination and seedling growth. We evaluated the correlation between pepper morphoagronomic traits and resistance to ethylene on ornamental peppers. Two genotypes, one resistant (UFPB 132), a susceptible (UFPB 134), and two hybrids (DR x PN) were utilized (76 x PN) to assess the susceptibility or resistance to ethylene. The experimental design was completely randomized, with four replications. First, 19 morphoagronomic characteristics were analyzed when the plants had 30% of fruits at the ripe stage. At this stage, the pots were transferred to a room at 25oC with 8-10 µmol/s/m2 of white fluorescent light. Afterwards, the pots were placed in a 60-L container and treated with ethylene at final concentration of 10 µL/L. The plants were exposed to ethylene for 48 hours and then kept at room temperature for further analysis. Afterwards, the number of leaves and fruits was determined at time zero and after 144 hours after end of the ethylene treatment. The Pearson correlation was calculated for each pair of variables and submitted to t-test (p≤0.05). We observed high occurrence of a significant positive correlation (>0.95) between leaf abscission and the anther length, major fruit width, pedicel length, pericarp thickness and dry matter content of the fruits. No significant correlation between fruit abscission and morphological evaluated variables was found. These results show the possibility to use morphological measurements to select plants resistant to leaf abscission induced by ethylene, while for the abscission of fruits, No relation to the morphological parameters evaluated in this experiment was possible to be established.