Luciane Vilela Resende

Quantitative trait loci associated with resistance to gray leaf spot and grain yield in corn

A incorporacao de resistencia genetica a doencas e o aumento na produtividade de graos estao entre os principais objetivos dos programas de desenvolvimento de hibridos. A identificacao de locos de caracteres quantitativos (QTL) por meio de analises estatisticas associadas a marcadores moleculares possibilita a rapida obtencao de hibridos resistentes e produtivos. Nesta pesquisa, objetivou-se identificar locos de caracteres quantitativos (QTL) associados com resistencia a cercosporiose e com producao de graos em germoplasma de milho tropical. Foram utilizadas duas linhagens contrastantes em niveis de reacao a doenca (genotipos pertencentes a GENESEEDS - Ltda), seu hibrido F1 e a populacao segregante F2. Essas plantas foram fenotipadas quanto a resistencia a doenca e quanto a producao de graos e genotipadas com 94 marcadores de microssatelites. A associacao dos marcadores ao QTL foi realizada por meio de analises de marcas individuais, utilizando as metodologias de regressao linear e analise da maxima verossimilhanca. Observou-se que o tipo de efeito predominante no controle genetico da resistencia a cercosporiose foi o aditivo e para o controle genetico da producao de graos foi de dominância. Os marcadores microssatelites mais promissores para serem utilizados em estudos de selecao assistida para resistencia a cercosporiose sao umc2082 na posicao 4.03 e umc1117 na posicao 4.04 e para producao de graos, umc1042 e umc1058 nas posicoes 2.07 e 4.11.

Aplicação de técnicas multivariadas no estudo da divergência genética em cana-de-açúcar

Resumo - Estudos sobre divergencia genetica sao importantes na identificacao de genitores potenciais para a obtencao de novos individuos com maior efeito heterotico. Em cana-de-acucar esses estudos assumem fundamental importância, po is com o passar do tempo as variedades comerciais devem ser substituidas de suas areas de cultivo, devido a serios declinios agronomicos e industriais ocasionados pela degenerescencia varietal. Sendo assim, o objetivo deste trabalho foi avaliar a divergencia genetica em progenies de cana-de-acuca r, atraves de tecnicas multivariadas, com base em oito caracter es agroindustriais. O trabalho foi conduzido na area agricola da Usina Santa Tereza, municipio de Goiana (PE), durante o ano agricola 2007/2008. Foi utilizado o delineamento experimental casualizado em blocos completos com cinco repeticoes. As variaveis analisadas foram: toneladas de pol por hectare, toneladas de cana por hectare, fibra, pol % corrigida, pureza, teor de solidos soluveis, acucares redutores e acucar total recuperavel. Apos analise de variância e estimacao de parâ metros geneticos, a distância generalizada de Mahalanobis foi calculada para quantificar a dissimilaridad e. Foram utilizados o metodo hierarquico de ligacoes medias (UPGMA) e o metodo de otimizacao de Tocher. O coeficiente de herdabilidade media foi de alta magnitude para as variaveis TPH e TCH, indicando possibilidade de sucesso na selecao com base nesses caracteres. A metodologia aplicada permitiu a identificacao de progenies de maior divergencia genetica proporcionando ao fitomelhoramento canavieiro da RIDESA sugestao de cruzamentos a serem realizados futuramente. Palavras-chave - Cana-de-acucar. Hibridacao vegetal. Melhoramento genetico.This study aimed to evaluate the genetic diversity in progenies of sugar cane by means of multivariate techniques based on eight agroindustrial traits. The work was carried out in the agricultural area of Usina Santa Teresa, Goiana (PE), during the agricultural year 2007/2008. A complete randomized block design with five replications was used. The variables analyzed were: pol tons per hectare (PTH), sugarcane tons per hectare (STH), fiber (FB), corrected pol % (CPP), purity (PTY), content of soluble solids (BX), reducing sugar (RS) and total retrievable sugar (TRS). After analysis of variance and estimation of genetic parameters, the Mahalanobis distance was calculated for quantifying dissimilarity. We used average-linkage method (UPGMA) and the optimization method of Tocher. The average coefficient of heritability was high for the variables PTH and STH indicating the possibility of success in selection for these characters. The methodology allowed identification of progenies with greater genetic divergence providing information for RIDESA sugarcane plant breeding on crosses to be made in the future.

Variabilidade genética de acessos de araçazeiro e goiabeira suscetíveis e resistentes a Meloidogyne enterolobii

Guava culture stands for an important fruit-growing business in Brazil, with a greater and greater market. But, since 1989 severe damages to the culture caused by the nematode Meloidogyne enterolobii, have been reported. One the alternatives to solve this problem is the use of rootstocks with resistance to this nematode. This research aimed at the molecular characterization, with RAPD markers, of Psidium accessions susceptible to be utilized as rootstocks for the commercial guava trees. 30 primers were tested, from which 19 supplied distinct results for the amplification. The primers generated 163 polymorphic marks, resulting into a mean of 8,6 polymorphic bands per primer. The cluster analysis was performed per species, the accessions of Psidium sp presented the formation of two groups, one formed by A-UFLA accession and the other subdivided into four subgroups, that is, the accession with increased genetic distances, A-Ufla, resistant to M. enterolobii, A-Ufla4 and A-Ufla5, both susceptible to the nematode in issue, all collected in Lavras-MG with a similarity of about 66%. In the cluster analysis of the thirteen accessions of P.cattleyanum, it was possible to found the formation of two great groups. One made up by three accessions susceptible to M. enterolobii (A-20.2, A-10.1 and A-9.2) and the other group formed by ten accessions. The accessions grouped together according to the region of origin in six groups, the most divergent being that native to region of Lavras - MG, with 0.65 of similarity, where the genetic distances ranged from 0.88 to 0.65. The thirteen accessions of P. guineense, all susceptible to M. enterolobii, namely, 12 coming from Recife and one proceeding from Pelotas (A-14.1), grouped themselves together and two groups with similarity ranging from 0.59 to 0.83. As to the diversity study among the guava tree accessions, the greatest genetic distances were detected between the accessions G.P.S and G-Ufla with 0,71 Lavras-MG.

Utilização de marcadores moleculares RAPD e EST's SSR para estudo da variabilidade genética em cana-de-açúcar¹

Molecular markers of the type RAPD and ESTs SSR were used as tools to evaluate the variability, and estimate the genetic divergence between commercial varieties and sugarcane clones from self-pollination. Twenty-three genotypes from the Program for the Genetic Improvement of Sugarcane of the Interuniversity Network for the Development of the Sugar-alcohol Sector (PMGCA/RIDESA), were used in this study. The extraction of genomic DNA followed CTAB methodology, with modifications being made for sugarcane. Eleven RAPD oligonucleotides, obtained from Operon Technologies, and 7 ESTs SRR, found after an extensive review of the literature, were used. Analyses of genetic diversity were carried out using the GENES software. The RAPD markers detected a high degree of genetic polymorphism, producing 61 bands, of which 58 were polymorphic. The ESTs SSR markers amplified 38 alleles, 34 being polymorphic. Three groups being formed with the population studied. Most of the genetic variation was maintained among progeny, indicating the occurrence, for purposes of breeding, of a high degree of genetic variability among the genotypes of each progeny. Through estimated genetic divergence, it was possible to identify divergent parent plants, which could be used in hybridization in order to obtain superior clones with characteristics of interest to the sugarcane industry. The molecular markers RAPD and ESTs SSR were equally efficient in estimating the genetic variability in the genotypes tested, and in preparing crossbreeds to be used in breeding programs.

Nutritional Evaluation of Non-Conventional Vegetables in Brazil

The objective of this study was to characterize the nutritional compounds of interest present in vegetables known as non-conventional, in Brazil. The following evaluations were carried out: antioxidant activity, phenolic compounds, vitamin C, calories, carbohydrates, humidity, lipids, proteins, fiber, acidity and quantification of minerals (P, K, Ca, Mg, S, Cu, Fe, Mn, Zn and B). The species studied were Amaranthus hybridus L., Amaranthus viridis L., Basella alba L., Eryngium campestre L., Hibiscus sabdariffa L., Lactuca canadensis L., Rumex acetosa L., Stachys byzantina K. Koch, Tropaeolum majus L. and Xanthosoma sagittifolium L. Representative samples of plant structures of interest were harvested from each species suitable for human consumption such as leaves, flowers and flower buds. The results were submitted to multivariate analysis - principal components analysis (PCA). All the species present nutritional compounds of interest in different levels among the evaluated structures.

Número cromossômico e conteúdo de DNA nuclear em espécies do gênero Amaranthus (Amaranthaceae)

The objective of this work was to determine the chromosome number and nuclear DNA content of five species of the genus Amaranthus , which commonly occur in Brazil. Metaphase chromosomes were obtained through the flame drying technique and stained with 5% Giemsa, and DNA content was determined by flow cytometry. 2n=32 chromosomes were observed in A. hybridus and 2n=34 in the other studied species, indicating the occurrence of descendant dysploidy. The nuclear DNA content ranged from 1.28 to 1.79 pg, and A. deflexus had the highest value.

Variação estacional da oferta e preços de couve-flor em Minas Gerais

Em virtude da variedade de cultivares atualmente disponiveis, de suas diferentes exigencias climaticas e das diferencas climaticas entre as varias regioes produtoras, a couve-flor pode apresentar variacoes estacionais de oferta e de precos ao longo do ano. O objetivo do presente trabalho foi estudar a variacao estacional da oferta e dos precos da couve-flor praticados no Estado de Minas Gerais, representados pelas unidades da CEASAMINAS, bem como as componentes dessa oferta para cada principal regiao abastecedora do Estado, no periodo de 2005 a 2009. A unidade CEASAMINAS (Grande BH) foi responsavel por 68% da comercializacao anual de couve-flor em Minas Gerais por meio das unidades da CEASAMINAS, que oscilou entre 9.420 e 10.937 toneladas anuais. A quase totalidade de producao proveio de municipios mineiros, localizados em quatro grandes mesorregioes: Regiao Metropolitana de Belo Horizonte, Campo das Vertentes, Triângulo Mineiro e Vale do Rio Doce, que representaram, respectivamente, 49%, 28%, 9% e 6% da oferta anual. As variacoes estacionais de oferta refletiram claramente as limitacoes dos cultivares atualmente disponiveis e a necessidade de novos cultivares que possam tolerar as grandes oscilacoes de temperatura nos meses de meia estacao. Tambem ficou evidente que, a despeito da disponibilidade de cultivares de verao, a producao de couve-flor ainda e mais baixa nessa epoca do ano, um reflexo provavel da alta precipitacao que ocasiona maiores perdas por doencas na lavoura e em pos-colheita.

Overcoming strawberry achene dormancy for improved seedling production in breeding programs

espanolLos aquenios de la fresa presentan latencia del tegumento. Este hecho, unido a la baja eficiencia de la polinizacion artificial implica en la realizacion de un mayor numero de cruzamientos para asegurar el numero minimo de aquenios utilizados en la produccion de plantulas en programas de mejoramiento. El objetivo de este estudio fue el de probar soluciones quimicas para superar la latencia en aquenios de la fresa con el fin de aumentar la germinacion y el indice de velocidad de germinacion (IVG). Este estudio consistio en dos experimentos. 1) Inmersion en H2SO4 (98%), HCl (37%) y NaClO (2%) para los tiempos de 0 (control), 10, 20, 35 y 50 minutos. 2) los aquenios se sumergieron en H2SO4 (98%) para los tiempos de 0 (control), 20, 25, 30, 35 y 40 minutos. Se utilizo un diseno completamente al azar (DCA) con cuatro repeticiones. La germinacion y el IVG fueron evaluados todos los dias durante 15 dias. La escarificacion con H2SO4 (98%) durante 40 min aumenta la germinacion de los aquenios de la fresa a 80% y puede ser utilizado como una tecnica para superar la latencia. La escarificacion con HCl y NaClO aumenta la germinacion y el IVG, sin embargo, debe estudiarse junto a otras concentraciones y tiempos de inmersion de esos metodos. EnglishStrawberry achenes present tegument dormancy. This fact, together with the low efficiency of artificial pollination requires a larger number of crossings to ensure the minimum number of achenes used in seedling production in breeding programs. The aim of this study was to test chemical solutions to overcome dormancy in strawberry achenes in order to increase the germination and Germination Speed Index (GSI). The study consisted of two experiments. 1) immersion in H2SO4 (98%), HCl (37%) and NaClO (2%) for 0 (control), 10, 20, 35 and 50 min were evaluated. 2) achenes were immersed in H2SO4 (98%) for 0 (control), 20, 25, 30, 35 and 40 min. A completely randomized design with four replications was used. Germination and GSI were assessed daily for 15 days. Scarification with H2SO4 (98%) for 40 min increased strawberry achene germination to 80% and can be used as a technique to overcome dormancy. Scarification with HCl and NaClO increases germination and the GSI, however, other concentrations and immersion times of those methods should be studied.