Estudo da diversidade genetica e da taxa de cruzamento em Stylosanthes spp. atraves de marcores microssatelites / Genetic diversity and mating system in Stylosanthes spp. as revealed by microsatellite markers

AUTOR(ES)

Melissa de Oliveira Santos Garcia

DATA DE PUBLICAÇÃO

2009

RESUMO

In Brazil, most of the cattle are grown in cultivated pastures. Forage grasses belonging to the African genus Urochloa P. Beauv. have been the most commonly used, together with some American legumes. Soil degradation and high costs for reclaiming are the major problems of pastures, since nitrogen enrichment is necessary. Considering that legumes can fix atmospheric nitrogen into soil, their use in consortium with grasses has been a plausible alternative for soil reclaiming. Among feasible legumes for pastures, those belonging to the genus Stylosanthes Sw. have proved to be suitable for low fertile soils and and for consortium with grasses. Brazil is the major center of origin and diversity of this genus, including its most promising species. Many Stylosanthes Sw. accessions are available in germplasm collections and their use could be potentiated by further knowledge on the available genetic diversity. In addition, there is still limited knowledge on the mating system of most of Stylosanthes Sw. species. In the present work, microsatellite markers were developed for S. capitata Vog., S. guianensis (Aubl.) Sw. and S. macrocephala Ferr. et Costa aiming at studying the genetic diversity and mating systems of Stylosanthes Sw. species. The microsatellite analysis on the mating system of S. capitata Vog. and S. guianensis (Aubl.) Sw. showed a mixed mating system with predominance of self-fertilization. Considering that Stylosanthes flowers are cleistogamous, the observed outcrossing rates wererelatively high, being 26% for S. guianensis (Aubl.) Sw. and 31% for S. capitata Vog.. These outcrossing rates should be taken into consideration in seed multiplication, for the purpose of maintaining the genetic integrity of individual accessions. Variation in the estimates of outcrossing among different progenies was observed. The microsatellite studies on the genetic diversity in S. guianensis (Aubl.) Sw. and S. macrocephala Ferr. et Costa demonstrated that there are genetic distinct groups within the germplasm collection that could be useful for breeding purposes. In S. guianensis (Aubl.) Sw., which has a controversial taxonomy, the observed groups were in agreement with one of the proposed taxonomical classification. The microsatellites developed for Stylosanthes Sw. species and the data on mating system and genetic diversity presented herein represent important knowledge and tools towards the understanding of this genus and are potentially useful for further studies.

ASSUNTO(S)

microssatelites (genetica) plantas - melhoramento genetico plantas forrageiras leguminosa microssatelites (genetic) plant-breeding forage plants legumes

Documentos Relacionados

• Avaliação da variabilidade genética em Musa spp. utilizando marcadores microssatélites.
• DIVERSIDADE GENÉTICA EM ACESSOS DE Stylosanthes spp. UTILIZANDO DESCRITORES MORFOAGRONÔMICOS
• Diversidade Genética e estrutura espacial intrapopulacional em Tibouchina papyrus(POHL) Toledo utilizando marcadores microssatélites.
• Variabilidade genetica e estrutura de populações de Cochliomyia hominivorax (Diptera: Calliphoridae) : uma nova perspectiva atraves de marcadores microssatelites
• Genetic diversity reduction in improved durum wheat cultivars of Morocco as revealed by microsatellite markers