Variabilidade genética e conservação de Cucurbita maxima Duchesne pela Agricultura Familiar na Amazônia Centro-Ocidental

Abstract

The Cucurbita maxima (Duchesne) is a vegetable crop plant cultivated and maintaned by traditional communities. Although Brazil is considered a center of diversity of pumpkins and squash, there is few knowledge about the germplasm maintained by family farming in the Amazon. The situation is worsened by the possibility of disappearance of local populations of this specie, taking into account the today changes promoted in family farming. The aim of this study was to describe and characterize the current forms of management and the genetic resource conservation process of the vegetable known as regional pumpkin (C. maxima) by family farmers of lowland ecosystem in the regions of Solimões River, Amazon. The specific objectives were to identify the areas of occurrence of regional pumpkin conservation practice by family farmers and techniques and management of the species and its implications for the conservation of genetic diversity and evolution of the species; estimate current levels of genetic variability between and within local cultivars through estimation techniques of genetic parameters and use of molecular markers; and estimate the levels of adaptability and phenotypic stability of local cultivars of C. maxima. The first chapter referred to the conservation of genetic resources in situ regional pumpkin (C. maxima) by farmers in the Central Western Amazon. The study used qualitative methods with application of structured interviews and visit to the planting area. The second chapter investigated the genetic variability in local cultivars of regional pumpkin kept by floodplain farmers of the Central Western Amazon. Estimation techniques were applied genetic parameters from field testing, characterization of the qualitative and quantitative morphoagronomic descriptors, the evaluation of index of lost of sanity and index of virus occurrence. To study the variability by molecular analysis we used the technique of molecular marker Amplified of Fragment Length Polymorphism - AFLP. The third chapter has a study about estimation of adaptability and phenotypic stability parameters in local cultivars of regional pumpkin. This study showed that family farming is responsible for the conservation of regional pumpkin (C. maxima) in the floodplains of the Central West Amazonian. It was concluded that the management forms adopted by family farmers to keep the identities of local cultivars is efficient and by other side the sample obtained within local varieties is more efficient when confronted with samples obtained between local cultivars. Local cultivars grown and maintained by family farmers have genetic adaptability levels and phenotypic stability consistent as those presented by commercial cultivar “Xingo Jacarezinho”