Elizanilda Ramalho do Rêgo

Avaliação do coeficiente de variação experimental para caracteres de frutos de pimenteiras

O objetivo deste estudo foi formular uma classificacao para coeficientes de variacao, de experimentos com pimentas do genero Capsicum, para utilizacao em seis variaveis morfologicas do fruto. Foram selecionados 38 experimentos com resultados publicados, em que se constaram dados de caracterizacoes morfologicas do fruto e coeficientes de variacao (CV) das seguintes variaveis respostas: peso medio do fruto, comprimento do fruto, comprimento do pedunculo, maior e menor diâmetro do fruto e espessura do pericarpo. As faixas de classificacao dos CV foram baseadas na metodologia proposta por Garcia (1989), que considera a propriedade da distribuicao normal do CV. Pelo teste de Lilliefors, a 5% de probabilidade, todas as variaveis satisfizeram a pressuposicao de distribuicao normal do CV. As faixas de classificacao do CV, obtidas para essas seis variaveis, foram distintas daquelas da classificacao geral, proposta por Gomes (2000). Ademais, constatou-se que as classificacoes dos coeficientes de variacao de variaveis morfologicas de pimenteiras do genero Capsicum dependem da variavel resposta, sendo que as maiores faixas de classificacao de CV ocorreram para menor diâmetro do fruto, espessura do pericarpo e peso medio do fruto.

Tamanho de amostra para caracterização morfológica de frutos de pimenteira

O objetivo deste estudo foi determinar o tamanho apropriado de amostra por meio da tecnica de simulacao de subamostras para a caracterizacao de variaveis morfologicas de frutos de oito acessos (variedades) de quatro especies de pimenteira (Capsicum spp.), que foram cultivadas em area experimental da UFPB. Foram analisados tamanhos reduzidos de amostras, variando de 3 a 29 frutos, com 100 amostras para cada tamanho simulado em um processo de amostragem com reposicao de dados. Realizou-se analise de variância para os numeros minimos de frutos por amostra que representasse a amostra de referencia (30 frutos) em cada variavel estudada, constituindo um delineamento experimental inteiramente casualizado com duas repeticoes, onde cada dado representou o primeiro numero de frutos na amostra simulada que nao apresentou nenhum valor fora do intervalo de confianca da amostra de referencia e que assim manteve-se ate a ultima subamostra da simulacao. A tecnica de simulacao utilizada permitiu obter, com a mesma precisao da amostra de 30 frutos, reducoes do tamanho amostral em torno de 50%, dependendo da variavel morfologica, nao havendo diferencas entre os acessos.

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

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.

An alternative procedure for performing a power analysis of Mantel's test

This study proposes a simple way to perform a power analysis of Mantels test applied to squared Euclidean distance matrices. The general statistical aspects of the simple Mantels test are reviewed. The Monte Carlo method is used to generate bivariate Gaussian variables in order to create squared Euclidean distance matrices. The power of the parametric correlation t-test applied to raw data is also evaluated and compared with that of Mantels test. The standard procedure for calculating punctual power levels is used for validation. The proposed procedure allows one to draw the power curve by running the test only once, dispensing with the time demanding standard procedure of Monte Carlo simulations. Unlike the standard procedure, it does not depend on a knowledge of the distribution of the raw data. The simulated power function has all the properties of the power analysis theory and is in agreement with the results of the standard procedure.