Genetic Resources of Triticum

Abstract

The political framework and the development of molecular biology and electronic data management caused a general paradigm shift in plant genetic resources (PGR), exemplifi ed here for wheat. (1) In situ versus ex situ maintenance of PGR. Ex situ maintenance lost predominance. Wild wheats are effectively maintained in the wild; landraces do well on farm. New methods did not lead to the expected progress. (2) Inclusion of neglected and underutilized crop species. Some species are probably extinct in traditional cultivation areas, whereas landraces were recently found for others. Wild relatives have gained importance in wheat breeding: besides wild Triticum species, also Aegilops , Secale , Hordeum and other genera are used. × Triticosecale reached world importance; × Tritordeum will follow soon. (3) Methods of analysing diversity within and between taxa. New technology yields new insights in the structure and evolution of populations. (4) Genetic erosion is a problem, also inside genebanks. (5) Landraces show complex morphological diversity. Infraspecifi c classifi cation systems are useful for their characterization and handling, but less recognised by breeders. (6) Methods of evaluation. Molecular markers identify genetic differences on a fairly simple level without reference to ecological adaptation. (7) Genebanks should expand classical evaluation programmes. Pre-breeding will gain importance. (8) Storage and reproduction in genebanks is done effectively and cost-effi ciently under long-term conditions, but strategic concepts for reproduction are needed. Traditional methods are often neglected, and modern possibilities over-emphasized. Maintenance of landraces in genebanks and on farm poses challenges. PGR work is conservative. Landraces can be studied by traditional methods; molecular methods can resolve specifi c questions.

Potential of Wild Relatives of Wheat: Ideal Genetic Resources for Future Breeding Programs

“…Wild wheats are successfully preserved in the wild, while landraces thrive in the field. The predicted improvement was not achieved using new approaches [53]. II.…”

“…Over the last three decades, many studies have been performed to characterize the genetic diversity in ancestral and wild relatives of wheat based on different molecularmarker systems. A general pattern change in plant genetic resources (PGR) was triggered by the political system, as well as the advancement of molecular biology and electronic data processing, as seen here for wheat [53]:…”

“…Some plants are likely extinct in conventional farming zones, although landraces for others have only recently been discovered. Wild relatives have become increasingly important in wheat breeding, with Secale, Aegilops, Hordeum, and other genera being used in addition to wild Triticum varieties [53]. III.…”

“…The role of PGR is traditional. Orthodox approaches can be used to study landraces, but molecular methods can answer complex questions [53]. According to numerous studies, a high level of genetic diversity among wild relatives of wheat has been reported, which may refer to their natural distributions in a wide range of ecosystems and even in natural hybridization among various species.…”