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Molecular Study of the Genetic Variability of Pumpkins Landraces from Brazilian Amazon  [PDF]
Lúcia Helena Pinheiro Martins, Maria Teresa Gomes Lopes, Hiroshi Noda, Pedro de Queiroz Costa Neto, Ayrton Luiz Urizzi Martins, Fabíola Viana de Almeida, Liane Cristine Rebou?as Demosthenes
Agricultural Sciences (AS) , 2018, DOI: 10.4236/as.2018.94035
Abstract: The Cucurbita maxima Duchesne is a vegetable crop plant cultivated and maintained by traditional Amazon communities, Brazil. The situation is worsened by the possibility of disappearance of local populations and genetic variability of this specie, taking into account the today changes promoted in family farming. The aim of this study was to estimate the current levels of genetic variability of local cultivars through the use of molecular markers (Amplified Fragment Length Polymorphism—AFLP). We chose to collect in two distinct micro regions in order to identify possible influences of geographic isolation and different levels of market requirements in the conservation of the genetic variability of the C. maxima. For the molecular analysis, bulk samples of fresh leaves of 15 plants/half-sibling family were collected in paper bags. There were 34 samples from the half-sib families. The analysis of the results half-sib obtained by methods of estimation of genetic variation by molecular markers shows that the forms of cultivation and management adopted by family farmers maintain the identities of the local/landraces (native cultivars) and, at the same time, the levels of diversity for the assurance of adaptability macro-environmental.
Genetic variability of Brazilian rice landraces determined by SSR markers
Borba, Tereza Cristina de Oliveira;Mendes, Clistiane dos Anjos;Guimar?es, élcio Perpétuo;Brunes, Tuliana Oliveira;Fonseca, Jaime Roberto;Brondani, Rosana Vianello;Brondani, Claudio;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009000700009
Abstract: the objective of this study was to evaluate the genetic variability of rice (oryza sativa) landraces collected in brazilian small farms. twelve simple sequence repeat (ssr) markers characterized 417 landraces collected in 1986, 1987 and 2003, in the state of goiás, brazil. the number of landraces with long and thin grain type increased in the evaluated period, probably due to market demand. based on the molecular data, the genetic variability increased during this period and, as per to the factorial correspondence analysis, most of the accessions were grouped according to the year of collection. the incorporation of modern rice cultivars in landrace cultivation areas and the selection carried out by small farmers are the most probable factors responsible for increasing landrace genetic variability, during the evaluated period. genotype exchange between farmers, selection practice and local environmental adaptation are able to generate novel adapted allele combinations, which can be used by breeding programs, to reinitiate the process.
Phenotypic variability among pumpkin accessions in the Brazilian semiarid
Borges, Rita Mércia E;Resende, Geraldo M de;Lima, Maria Auxiliadora C de;Dias, Rita de Cássia S;Lubarino, Paloma Clementino da C;Oliveira, Regina Célia da S;Gon?alves, Nadja Pollyanna da S;
Horticultura Brasileira , 2011, DOI: 10.1590/S0102-05362011000400003
Abstract: the aim of this study was to estimate the phenotypic divergence among fourteen pumpkins accessions of the cucurbits germplasm active bank of embrapa semiárido, in order to support breeding program to these species. nine morphoagronomic descriptors were analyzed by the principal components and by upgma techniques. in the analysis of principal components, the formation of three contrasting clusters was observed, each one composed of two accessions. there occurred also the formation of one core group composed of five accessions, being the accessions called 683 and 684 collected in bahia and the other in maranh?o. the most divergent accessions were 620, 624 and 748. the variables of the greatest contribution to the genetic divergence were diameter, weight and average length of the fruit. in the upgma analysis, obtained from the symmetric matrices generated by the mahalanobis distance for the nine descriptors, there was the formation of one core group, composed of ten accessions, whose similarity was 45.71%, with geographically divergent accessions presenting the greatest similarity. three accessions were not clustered with others. the study identified phenotypic variability for the analyzed characters and the absence of relationship between place of collection and phenotypic diversity.
Regional Climate Variability Responses to Future Land Surface Forcing in the Brazilian Amazon  [PDF]
Tao Zhang,Jinyan Zhan,Feng Wu,Jiao Luo,Juan Huang
Advances in Meteorology , 2013, DOI: 10.1155/2013/852541
Abstract: Tropical deforestation could destabilize regional climate changes. This paper aimed to model the potential climatological variability caused by future forest vulnerability in the Brazilian Amazon over the 21th century. The underlying land surface changes between 2005 and 2100 are first projected based on the respectable output produced by Hurtt et al. Then the weather research and forecasting (WRF) model is applied to assess the impacts of future deforestation on regional climate during 2090–2100. The study results show that the forests in the Brazilian Amazon will primarily be converted into dryland cropland and pasture in the northwest part and into cropland/woodland mosaic in the southeast part, with 5.12% and 13.11%, respectively. These land surface changes will therefore lead to the significant reduction of the sum of sensible heat flux and latent heat flux and precipitation and the increase of the surface temperature. Furthermore, the variability of surface temperature is observed with close link to the deforested areas. 1. Introduction Anthropogenic climate changes have attracted worldwide concerns. The coupling mechanism between land surface vulnerability and hydrological and climatological variability has been increasingly investigated and assessed during the last decades [1–4]. Generally, changing in human dominated land use or natural vegetation covers has affected the climate conditions through biogeophysical and biogeochemical processes, by shifting the surface energy, thermodynamic momentum, moisture budget, and atmospheric components [5–9]. Large-scale land conversions, such as unprecedented urban area expansion [10, 11], intensified agricultural activities [12, 13], and high tropical and boreal deforestation rate [14], are mainly caused by the human land use practices directly or indirectly, which is to meet the demand of human immediate necessities [15–20]. As a result, these land conversions have had great corresponding repercussions on climate anomalies at different scales, as well as other adverse effects in terms of biodiversity decline, ecosystem degradation, and economic loss [21]. Though most current global climate concerns are focused on the first-order external forcing [22], such as the concentration of carbon dioxide (CO2) which primarily originated from the fossil fuels combustion and anthropogenic land use practices, the land surface changes which have influenced or will influence natural climate variability in history, current, and future have fascinated diverse community of scholars [23]. Forests, covering more than 30% of
Morphometric variability in populations of Palaemonetes spp. (Crustacea, Decapoda, Palaemonidae) from the Peruvian and Brazilian Amazon Basin
García-Dávila, Carmen Rosa;Magalh?es, Célio;Guerrero, José Camilo Hurtado;
Iheringia. Série Zoologia , 2005, DOI: 10.1590/S0073-47212005000300013
Abstract: morphometric variability among shrimp populations of the genus palaemonetes heller, 1869 from seven lakes (huanayo and urcococha, in peru; aman?, mamirauá, camale?o, cristalino e iru?anga, in brasil) in the amazon basin, presumably belonging to palaemonetes carteri gordon, 1935 and palaemonetes ivonicus holthuis, 1950, were studied. the morphometric studies were carried out from the ratios obtained from the morphometric characters. multivariated analysis (principal components analysis-pca, discriminant function analysis and cluster analysis) were applied over the ratios. intra- and interpopulation variations of the rostrum teeth, and the number of spines in the male appendix, were analyzed through descriptive statistics and bivariate analysis (spearman rank correlation test). results indicated a wide plasticity and overlapping in the studied ratios between populations. the principal components analysis was not able to separate different populations, revealing a large intrapopulation plasticity and strong interpopulation similarity in the studied ratios. although the discriminant functions analysis was not able to fully discriminate populations, they could be allocated in three subgroups: 1) cristalino and iru?anga; 2) huanayo, urcococha and camale?o and 3) mamirauá and aman?. the first two groups were morphometrically separated from each other, whereas the third one presented a strong overlap with the former two. the cluster analysis confirmed the first two subgroups separation, and indicated that the first and third groups were closely related. rostrum teeth and number of spines in the appendix masculina showed a large intrapopulation variation and a strong overlapping among the studied populations, regardless of the species.
Genetic variability in three Amazon parrot species
Lopes, IF.;Del Lama, MA.;Del Lama, SN.;
Brazilian Journal of Biology , 2007, DOI: 10.1590/S1519-69842007000500011
Abstract: parrots of the genus amazona are among the most threatened species of the order pscittaciformes. this work describes allozyme polymorphisms in three amazon parrot species - the blue-fronted amazon (amazona aestiva), the orange-winged amazon (amazona amazonica), and the festive amazon (amazona festiva) -, and provides useful data for the evaluation of their genetic variability. we electrophoretically analyzed blood samples from 68 wild-caught individuals, maintained in captivity in three brazilian zoos. eight of the ten studied enzyme loci exhibited polymorphism. glucosephosphate isomerase (gpi) proved to be a diagnostic locus for the identification of these amazon species. the expected average heterozygosity of the blue-fronted amazon (0.060) differed significantly from the expected heterozygosities of the orange-winged amazon and the festive amazon (0.040 and 0.039, respectively). this result was discussed as a consequence of hybridization between two geographic a. aestiva subspecies, and alternatively as a particular trait of this species. genetic variability of the blue-fronted amazon compared to birds in general is not low on a species-wide level, despite the fact that this parrot is one of the most illegally traded species. allozyme analysis proved to be an useful tool in monitoring the genetic variation within the genus amazona and can be applied in the management program of other threatened species of this genus.
Genetic variability among landraces of sesame in Ethiopia
DE Gebremichael, HK Parzies
African Crop Science Journal , 2011,
Abstract: Sesame (Sesamum indicum L.) is an ancient oil crop that has been referred to as the ‘Queen of oilseeds’ by virtue of its high quality oil. Ten Simple Sequence Repeats (SSRs) markers were used to study patterns of genetic variation within and among 50 sesame populations representing the existing Ethiopian collections. The number of alleles ranged from 6 to 17, with an average of 12.1 per locus. The Polymorphism Information Contents (PICs) of the markers ranged from 0.393 to 0.820. The observed heterozygosity (Ho) for landraces and cultivars ranged from 0.060 to 0.440 and 0.120 to 0.260, with a mean of 0.234 and 0.193, respectively, indicating the existence of higher heterozygosity within the landraces than cultivars. Landraces (He=0.377) showed higher Nei’s average genetic diversity than the cultivars (He=0.305). The fixation index (Fst) values for the landraces and cultivars were 0.427 and 0.26, respectively, indicating that genetic divergence between populations was smaller than genetic divergence within. High outcrossing of 45 and 46.4% for landraces and cultivars, respectively, indicates that both landraces and cultivars are line mixtures and segregants of past outcrossing results. A Neighbour-Joining dendrogram based on Modified Rogers’ Distances (MRD) and a principal coordinate analysis based on a simple dissimilarity matrix, points towards some grouping based on geographical origin. The established SSR markers will be very useful for further diversity analyses among a large landrace collection of Ethiopian sesame and in the establishment of a core collection. Moreover, existence of great genetic variability between the landraces is a good starting point of sesame crop improvement programs in Ethiopia.
Variability patterns in Ugandan pigeonpea landraces  [PDF]
EO Manyasa,SN Silim,JL Christiansen
Journal of SAT Agricultural Research , 2009,
Abstract: In-situ evaluation of pigeonpea cropping system andmanagement in Uganda and agro-morphologicalcharacterization of 29 pigeonpea landraces were studiedin 2001 and 2004/05, respectively. Results showed thatpigeonpea in Uganda is predominantly intercropped withfinger millet and to some extent with maize and sorghum.Farmers largely used saved grain as seed and appreciatedthe damage by insect pests, but only farmers in Apachand Lira districts practiced any form of pest control.Observations across the collection districts indicated lowlevels of Fusarium wilt disease. Agronomic evaluation ofthe 29 accessions revealed differential adaptation at thetwo test locations in Kenya with accessions expressing adelayed phenology at the cooler Kabete relative to thewarmer Kampi ya Mawe. Lower 100-seed weight wasreported at Kabete relative to Kampi ya Mawe possiblydue to excessive vegetative growth at Kabete. Clusteranalysis delineated the germplasm into four clusters allseparated from the adapted medium- and long-durationchecks. Although overall two distinct diversity groupswere observed separating the short, medium-maturingtypes from the tall late- and very late-maturing types, theseparation was relatively marginal suggesting a closergenetic relation between the Ugandan pigeonpeagermplasm. Relatively low diversity in qualitative traitswas observed in the accessions. The predominance ofaccessions with pubescent pods, a trait associated withresistance to pod damaging insects may provide anopportunity to identify materials for insect pest resistancefor use in breeding.
Ján Brindza,Vladimír Vietoris,Lucia Kucelová,Maria Fil
Potravinarstvo : Scientific Journal for Food Industry , 2011, DOI: 10.5219/137
Abstract: The goal of study was analysis of morphological characteristics and organoleptic attributes of traditional food products from the pulp of regional varieties of pumpkin (Cucurbita spp.). For experimental purposes we used a landrace from Ukraine (A) and 5 landraces from Serbia (B, C, D, E and F). For the fruit of all landraces were determined by the average weight of fetuses in the range 1025.0 g (F) - 7680.0 g (B), stem weight 3.35 g (F) - 25 g (B), pulp weight 668.15 g (F) - 6351.10 g (B), placental weight of 90.47 g (E) - 515.50 g (B), seed weight 44.55 g (F) - 277.80 g (B) and mass exocarp 124.20 g (E) - 471.70 g (B). The dry matter content of flesh were determined in the range 7.8 to 11.6 %. The total weight of the fruit pulp was determined by weight in the range of 65.19 up to 88.50 % and the proportion of seed weight in the range of 1.65 to 6.58 %. Differences between genotypes were determined by the texture attributes of dry pulp of selecte
Variability and genetic differentiation among Anopheles (Ano.) intermedius Chagas, 1908 and Anopheles (Ano.) mattogrossensis Lutz & Neiva, 1911 (Diptera: Culicidae) from the Brazilian Amazon
Santos, Joselita Maria Mendes dos;Rodriguez, Gloria Alicia Diaz;Maia, Juracy de Freitas;Tadei, Wanderli Pedro;
Memórias do Instituto Oswaldo Cruz , 2005, DOI: 10.1590/S0074-02762005000600006
Abstract: anopheles (anopheles) intermedius and anopheles (ano.) mattogrossensis are brazilian anopheline species belonging to the scarcely studied anopheles subgenus. few studies have been done on the genetic differentiation of these species. both species have been found infected by plasmodium and are sympatric with other anopheline species from the nyssorhynchus subgenus. eighteen enzymatic loci were analyzed in larval specimens of an. intermedius and an. mattogrossensis aiming to estimate the variability and genetic differentiation between these species. an. mattogrossensis population showed higher genetic variability (p = 44.4 and ho = 0.081 ± 0.031) than that of an. intermedius (p = 33.3 and ho = 0.048 ± 0.021). most analyzed loci showed genotypic frequencies according to hardy-weinberg equilibrium, except for lap1 and lap2 in an. intermedius, and est1 and pgm loci in an. mattogrossensis. the genetic distance between these species (d = 0.683) was consistent with the inter-specific values reported for anopheles subgenus. we verified that the polymorphism and heterozygosity percentile values found in both species and compared to those in the literature, showed no relation between the level of isozyme variability and geographical distribution. the low variability found in these two species is probably more related to the niche they occupy than to their geographic distribution.
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