Potencial genético de variedades tradicionais de feijão-caupi e avaliação para resistência à murcha-de-Fusarium

• Ano de defesa: 2017
• Autor(a) principal: Araújo, Linda Brenna Ribeiro
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Vigna unguiculata; Marcadores moleculares; Fusarium oxysporum f. sp. tracheiphilum; Diversidade genética
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/25240

Traditional varieties are an important source of germplasm for several crops, and may present alleles that have long been lost, such as those that confer resistance to biotic and abiotic stresses. In the state of Ceará, the cultivation of the cowpea is highlighted because it is mainly carried out by family farmers who make use of these varieties, and their great adaptation to the region of cultivation and to the management adopted by the farmers can be used in the development of cultivars that better meet their demands. Thus, this work was carried out to evaluate the genetic potential of traditional varieties of cowpea collected from family farmers in the state of Ceará. In order to achieve this objective, laboratory analyzes, field and greenhouse tests were carried out. The laboratory analyzes consisted of the evaluation of the genetic diversity of the varieties through ISSR markers. The field experiments consisted of tests for the evaluation of morphological and agronomic descriptors in two environments: Fortaleza and Madalena, in the state of Ceará. The experiment in greenhouse was conducted to evaluate the existence of sources of resistance to Fusarium wilt by the root-dipping inoculation method. The ISSR markers selected for the study were efficient in identifying the genetic variability of the species, presenting high values of polymorphism and polymorphism information content (PIC). Even so, the genetic distance found between the studied varieties ranged from 0,05 to 0,31, values considered low and that suggest a narrow genetic base of the species. Some traditional varieties evaluated showed higher grain yield than commercial cultivars for the evaluated environments (3286.66 tons/ha), indicating a high agronomic potential and a great environmental adaptation. They presented greater genetic variability for the morphological characters evaluated, when compared to the molecular data. Regarding the severity of the disease, the varieties formed three distinct groups. The group with the lowest severity of the disease (25,00 to 32,50 %) consisted of thirty-seven varieties, the second group with intermediate values of severity (33,75 to 37,50 %) consisted of eight varieties and in the third Group were the five varieties that presented the highest values of severity (41,25 to 51,25 %). The varieties with the best results for agronomic traits, resistance to Fusarium wilt and greater genetic distance are promising for use in breeding programs.