Identification of duplicates of cassava accessions sampled on the North Region of Brazil using microsatellite markers

Abstract

Duplicates are common in germplasm banks and their identification is needed to facilitate germplasm bank management and to reduce maintenance costs. The aim of this work was to identify duplicates of cassava from a germplasm bank in Eastern Amazon, which had been previously characterized both morphological and agronomically. In order to be genotyped with 15 microsatellite loci, 36 accessions were selected. These accessions were classified into 13 groups of similar morpho-agronomical characteristics. All loci were polymorphic, and 75 alleles were identified, with an average of five alleles per loci and H E = 0.66. There were determined 34 pairs of genotypes with identical multiloci profiles and the probability of genetic identity was 1.1x10-12 with probability of exclusion of 99.9999%. Among these duplicates, there are accessions sampled on different years and places, but with different names and accessions with the same name sampled in different places and years. The study identified genotypes that are grown in different places and that have been maintained over the years by local farmers. KEYWORDS: Manihot esculenta; germplasm; molecular markers Identificação de duplicatas em acessos de mandioca coletados na Região Norte do Brasil por meio de marcadores microssatélites RESUMODuplicatas costumam ocorrer em bancos de germoplasma e a sua identificação é necessária para facilitar o manejo dos bancos ativos de germoplasma (BAGs) e diminuir custos de manutenção. O objetivo deste trabalho foi identificar duplicatas de mandioca determinadas previamente pela caracterização morfo-agronômica, em um BAG da Amazônia Oriental. Foram selecionados 36 acessos que se agrupavam em 13 grupos de similaridade morfo-agronômica para serem genotipados com 15 locos microssatélites. Todos os locos foram polimórficos, sendo obtidos 75 alelos, com média de cinco alelos por loco e H E = 0,66. Foram encontrados 34 pares de genótipos que apresentaram perfis multilocos idênticos e a probabilidade de identidade genética foi de 1,1x10 -12 com probabilidade de exclusão de 99,9999%. Entre essas duplicatas, estão materiais coletados em épocas e locais diferentes, e com diferentes denominações e acessos com o mesmo nome coletados em diferentes locais e anos. O estudo identificou genótipos que vem sendo cultivados em diferentes locais e que vêm sendo mantidos pelos agricultores ao longo dos anos.

Molecular characterization of accessions of a rare genetic resource: sugary cassava (Manihot esculenta Crantz) from Brazilian Amazon

“…The high incidence of duplicates is an indicative of exchanges among farmers from different places and also an evidence that sugary cassava in the Northeast of Pará is represented by a single genotype that may have suffered some mutations all over the years. It could be expected, considering the asexual propagation of the species and high exchange of vegetative parts among farmers, as detected in communities in the Amazon (Peroni et al 2007;Moura et al 2013) or in other regions of natural occurrence of cassava (Dyer et al 2011). It has been stated that cassava populations Analysis was performed after the removal of duplicated accessions Fig.…”

“…Total genomic DNA was extracted according to procedure similar to Doyle and Doyle protocol (1990) and described in Moura et al (2013). DNA was quantified on 1 % agarose gel using lambda phage DNA at different concentrations (50, 100 and 200 ng/ lL) as pattern.…”

Research Article Genetic diversity of cassava landraces cultivated in northern Mato Grosso State, Brazil, using microsatellite markers

“…This native Brazilian plant is grown across almost the entirety of the country's territory (Flora do Brasil, 2020). Its genetic variability allows it to adapt to different edaphoclimatic conditions (Moura et al, 2013).…”

“…In the central-west region of the country, cassava is grown mainly on family farms due to its easy propagation, adaptation to different soilclimatic conditions and productive potential. The produce is targeted towards own consumption, animal feeding and agro-industries (Marchetti et al, 2013;Moura et al, 2013;Tumuhimbise et al, 2014).…”

Research Article Variability among Capsicum baccatum accessions from Goiás, Brazil, assessed by morphological traits and molecular markers.

“…Such knowledge is achieved by means of characterization, and it provides the basis for plant breeding (Moura et al, 2013). Morphological characterization allows the description, identification, and differentiation of accessions of the same species and provides estimates of the germplasm collection variability (Carvalho et al, 2014).…”