Data/hora: 01/06/2024 14:30:34

Biblioteca(s): | Embrapa Mandioca e Fruticultura.
Data corrente: | 14/04/2004
Data da última atualização: | 14/04/2004
Autoria: | CHAVARRIAGA, P.; MAYA, M. M.; DUQUE, M. C.; IGLESIAS, C.; FREGENE, M.; TOHME, J.; BONIERBALE, M.; KRESOVICFI, S.; KOCHERT, G.
Título: | Microsatellites in cassava (Manihot esculenta Crantz, Euphorbiaceae): discovery, inheritance, variability and uses for germplasm characterization.
Ano de publicação: | 1998
Fonte/Imprenta: | Revista Brasileira de Mandioca, Cruz das Almas, v.17, p.23, nov, 1998. Suplemento.
Idioma: | Inglês
Conteúdo: | Abstract: Cassava germplasm characterization and maintenance can be more efficient by the combined use of DNA-based molecular markers and high-throughput genotyping systems. In the present study, microsatellite markers were developed in cassava, and their mode of inheritance, variability and use for germplasm characterization was studied using fluorescence-based, semi-automated genotyping, and radioactive-based genotyping. Chi square test (X') were performed to analyse segregation and linkage between microsatellite alleles in an FI mapping population (cross CM7857). Most loci segregated in the expected 1- 1, 1: 2: 1 or 1: 1: 1: I ratio. Linkage and segregation distortion was also detected between few loci. Microsatellite heterozygosity (h) was estimated in 48 and 500 accessions of the core collection using radioactive-based and fluorescence-based genotyping respectively. Heterozygosity ranged from 0.00 to 0.88 and the number of alleles varied from I to 15. Microsatellite allele frequencies varied among countries in the core. Colombia and Brazil had the largest number of different alleles over all loci. Mexico also showed a higher number of different alleles over all loci. Unique alleles were present in accessions from Brazil, Colombia, Guatemala, Venezuela and Paraguay. The Rst statistic indicated between-country differentiation in microsatellite allele size variation. Approximately 80% of microsatellite detected one or two alleles per accession, suggesting a low degree of microsatellite loci duplication. The identification of potential duplicates within the core collection was done using four microsatellite loci and fluorescence-based genotyping. Duplicates were confined through morphological characterization and (x-p-esterase and AFLP profiling. Brazil and Colombia showed no duplicated accessions. Seven potential duplicates were identified among accessions from Guatemala, Paraguay and Venezuela. Potential duplication was estimated to be about 1.34% in the core collection. The data presented here is intended to complement already existing databases used for efficient cassava germplasm characterization and maintenance, and for the definition of gene pools in cassava.
Categoria do assunto: | --
Registro original: | Embrapa Mandioca e Fruticultura (CNPMF)
Exemplares: | CNPMF - (20938-1) - ADD - AP - -- - 633.68205 -  -  - DIS