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Farm seed opportunities : a project to promote landrace use and renew biodiversity

This review outlines innovative methods for garlic breeding improvement and discusses the techniques used to increase variation like mutagenesis and in vitro techniques, as well as the current developments in florogenesis, sexual hybridization, genetic transformation and mass propagation. Sexual sterility of garlic reduces its potential for improvement of desired traits. Restoring fertility in this crop, which has been vegetatively propagated for millenia, provides new genetic possibilities for breeding purposes and/or genetic studies. In this context the recent developments on the manipulation of garlic florogenesis are discussed and it is shown that specific environmental conditions might allow for fertility restoration and seed production in bolting garlic. Furthermore the introduction of Agrobacteriummediated and biolistic gene transfer systems in garlic, a species known for its recalcitrant behaviour in in vitro culture, are reviewed. Attention is paid to the development of a high quality callus year-round production method for transformation. Also the first garlic transgenics resistant to beet army worm (Spodoptera exigua) and herbicides will be introduced. Garlic friable embryogenic calluses are of pivotal importance for the establishment of cell suspension cultures needed for rapid multiplication of elite garlic genotypes. The development of these suspension cultures are discussed in this review. It is shown that a large number of somatic embryos (potentially 8 x 109 to 1011) can be produced annually, from a single clove, for each current variety and that the conversion into plantlets amounts approximately 50%. (Résumé d'auteur

Arbuscular mycorrhizal fungi (AMF) play an important role in the uptake of nutrients and water from soil. Onions, Allium cepa L., are plants with a shallow root system. As a result, onion plants need a lot of fertiziler for their growth. Furthermore, onion plants are sensitive to drought. The aim of the current research project is to study the beneficial effect of mycorrhizal fungi on the growth and development of Allium species and to determine whether it is possible to improve onions for mycorrhizal responsiveness by means of breeding. Variation among Allium species and segregation observed in a interspecific tri-hybrid population indicate that selection and thus breeding for high responsiveness to AMF is possible.