Isozymic variability in a Brazilian collection of annatto (Bixa orellana L.)

Abstract

-The objectives of this work were to optimize the isozyme electrophoresis technique for Bixa orellana, and use isozyme markers for a preliminary survey on the genetic variability in Brazilian annatto germplasm accessions. Collection consisted of seed samples from sixty open pollinated trees, representing two Northern and four Southern geographic provenances. The extraction, electrophoresis, and interpretation of annatto isozymes are described. Three out of the twenty-one identified isozyme loci were polymorphic in the collection. The percentage of polymorphic loci (P = 21.05) and the expected heterozygosity in annatto (H T = 0.064) were low, compared to other tropical woody species. A UPGMA phenogram, constructed with Nei's genetic distances, clearly separated the germplasm provenant from North and Central Brazil. Variability was significantly higher among the accessions from Maranhão. A sharp genetic differentiation was detected between accessions from Maranhão and Pará States, despite their geographical proximity. The distinctive isozyme polymorphism, observed in the accessions from Maranhão, together with reports on local morphological heterogeneity in annatto fruit shape, color, and pubescence, calls for more detailed genetic and taxonomic investigation.Index terms: germplasm, lipstick plant, genetic variability, allozyme, phenogram. Variabilidade isoenzimática em uma coleção brasileira de urucum (Bixa orellana L.)Resumo -Os objetivos deste trabalho foram: otimizar a técnica de eletroforese de isoenzimas para Bixa orellana, e usar marcadores isoenzimáticos para um estudo preliminar da variabilidade genética, presente em uma coleção de germoplasma de urucum. Foi estudada uma coleção de amostras de sementes oriundas de 60 indivíduos de polinização aberta, que representam duas procedências do Norte e quatro do Sul do Brasil. São descritas a extração, a eletroforese e a interpretação de isoenzimas de urucum. Três, dos vinte e um locos isoenzimáticos identificados, foram polimórficos na coleção examinada. A porcentagem de locos polimórficos (P = 21,05) e a heterozigosidade esperada em urucum (H T = 0,064) foram baixas, em comparação com outras espécies arbóreas tropicais. O dendrograma UPGMA, construído com base nas distâncias genéticas de Nei, diferenciou claramente as procedências de urucum do Norte, daquelas oriundas do Brasil Central. A variabilidade foi significativamente superior na procedência Maranhão. Uma pequena diferenciação genética foi detectada entre os acessos do Maranhão e do Pará, apesar da proximidade geográfica. O polimorfismo isoenzimático diferenciado, observado no germoplasma procedente do Maranhão, somado a relatos de heterogeneidade morfológica local com relação à forma, à cor e à pubescência dos frutos de urucum, sugerem uma investigação genética e taxonômica mais detalhada dessa espécie.Termos para indexação: germoplasma, variabilidade genética, urucum, aloenzima, dendrograma.

Cytogenetics and Reproductive Biology of <i>Bixa orellana</i> L. (Bixaceae)

“…3) showing that B. orellana is self-compatible. This fact also reinforces the existence of maturing synchrony between stigma and pollen proposed by Almeida and Pinheiro (1992), although we may not discard the protandry presented by Gómez (1980) due to the increased genetic variability presented by Carvalho et al (2005c) for B. orellana populations.…”

Isolation and characterization of microsatellite loci for Bixa orellana, an important source of natural dyes

“…This low level of polymorphism (40%) was also obtained by other authors working with Bixa orellana. Carvalho et al (2005) evaluated 60 genotypes annatto maintained in germplasm collections from various regions of Brazil and concluded that only 3 of the 21 isozyme loci were polymorphic (14.3%).…”

“…Isozyme markers (Medina et al, 2001;Carvalho et al, 2005) have been used to study the genetic diversity among accessions from Venezuela and Brazil. DNA markers, such as sequence-related amplified polymorphism) (Valdez-Oheda et al, 2010) have also been used to examine the genetic diversity of annatto accessions from Mexico, and an amplified fragment length polymorphism protocol has also been established for this species (Fay et al, 2005).…”

Biodiversity of the urban homegardens of São Luís city, Northeastern Brazil

“…Some of them (e.g. Bixa orellana) are maintained for domestic use in folk medicine and/or in traditional cuisines (Carvalho et al 2005;Shilpi et al 2006), while others such as Cecropia spp. and Jatropha gossypiifolia have mainly medicinal uses (Castro et al 1999;Mariz et al 2006).…”