Collection of Bromus catharticus Vahl was carried out in the Argentine humid and subhumid central area. Sixty-eight natural populations are conserved for medium and long term in Pergamino Germplasm Bank and in IRB Germplasm Bank, and ten morphological and agronomic traits were evaluated in the field during two years. There was variability for the traits considered among the accessions. Those populations from the subhumid area showed differences in valuable attributes for breeding. Exploration of marginal areas for this species might be an effective way to add variability to this collection. Key words: evaluation, germplasm, prairie grass, plant breeding
CARACTERÍSTICAS DE POPULAÇÕES NATURAIS DEBromus cartharticus Vahl (Poaceae) COLETADAS NA ÁREA CENTRAL DA ARGENTINA RESUMO: Coletas de Bromus catharticus Vahl foram conduzidas nas areas úmidas e sub-úmidas centrais da Argentina. Sessenta e oito populações naturais foram mantidas por médio e longo períodos nos bancos de germoplasma Pergamino e IRB, e dez características morfológicas agronômicas foram avaliadas em campo durante dois anos. Foi observada variabilidade para as características entre os acessos. As populações da região sub-úmida mostraram diferenças para características importantes para o melhoramento. A exploração de áreas marginais para esta espécie pode ser um modo efetivo de adicionar variabilidade para esta coleção de germoplasma. Palavras-chave: avaliação, germoplasma, capim de pradaria, melhoramento de plantas
Plant genetic resources for food and agriculture are ex situ conserved in germplasm banks as samples (accessions) of natural or naturalized populations, either as the originally sampled propagules (mainly seeds) or their multiplications. The premises underlying ex situ conservation are that (a) it is the safest and cheapest alternative for germplasm preservation for future generations and (b) accessions are representative of the genetic diversity encountered in nature. In the past decades, ideas, alternatives and considerations have been put forward on the topic, and protocols have been devised for plant germplasm sampling, conservation and multiplication. However, limitations in the management efficiency of germplasm banks have been pointed out by international organizations. In our opinion, germplasm banks in general need to revise their functioning and management at the light of principles and methods of Genetics. To that end, it is necessary to consider the reproductive biology of higher plants -whose genetic consequences at both the individual plant and the population levels are not always either fully understood or taken into account in devising the protocols-, the genetic structures of wild and cultivated populations, and the course of the genetic material in the populations. In this paper, we discuss the three topics and provide an example of a national forage breeding program, from germplasm bank accessions as the germplasm of origin to the obtainment of commercial cultivars. Finally, we present a proposal as a base for discussion among curators, researchers and breeders.
Key words: accessions, breeding, genetic resources, germplasm banks, population genetics
Tall fescue (Festuca arundinacea Schreb.) is represented in Argentina by adapted populations of the continental morphotype, which are long persistent. It is the main perennial forage species cultivated in the temperate region of the country, producing forage for extensive grazing. The development of fescue plant breeding and its contribution to the achievement of higher productivity and better nutritional value with modern synthetic cultivars was the aim of this project. The characters considered were: adaptation and persistence in adverse environments, digestibility, leaf softness and tolerance to rust. The most representative cultivars of the stages and selection criteria considered in this work were: Pergamino El Palenque MAG, Palenque Plus INTA, Brava INTA, Baguala and Luján INTA.
Key words: tall fescue, plant breeding, cultivars, germplasm.
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