Main results from the EU-funded project "evaluation and utilization of pineapple genetic resources from the amazon to breed resistant varieties"

This project was aimed at obtaining knowledge and tools for the development of cultivars resistant to the main diseases in South America, by (i) characterizing and evaluating available genetic resources, (ii) studying the genetic structure of the genera Ananas and Pseudanas (iii) developing and applying resistance screening techniques for important pests and disease in the region, (iv) studying the heredity of agronomic traits, and (v) testing the potential of partial inbreeds in breeding. In addition, a standard database is being established in collaboration with IPGRI, to promote information on germplasm exchange. The project, which started in 1997 and ended in 2001, has produced an inventory of the germplasm held in its collections, allowing exchange and repatriation of lost germplasm. The list of descriptors has been revised. Multivariate analyses of the morphological data have produced consistent results. Molecular characterization, based on RFLP of genomic DNA and PCR-RFLP of cpDNA has confirmed the proximity of Ananas and Pseudananas, the absence of interspecific barriers in Ananas, the importance of a geographic component of variation, and the existence of a higher genetic diversity in the North of South America. Pineapple taxonomy has been revised. Genetic mapping was based on isozyme, RAPD, AFLP and ISSR markers and was carried out on a hybrid progeny between A. bracteatus and A. comosus, following the pseudotestcross approach. It resulted in a first map of 390 and 174 DNA markers distributed in 46 and 31 linkage groups for these two species. New sources of resistance to fusariosis have been identified, some of which show other interesting traits for the Brazilian producers. According to the first inheritance studies, this resistance seems monogenic and dominant, a result still to be confirmed. Selfprogenies obtained from the cultivars Perolera, Primavera, and Roxo de Tefé, showed inbreeding depression, but normal segregation for major leaf traits (spininess, colour). Subsequent hybridization of the inbreeds restored vigour.