Taxonomy and evaluation of genus Avena L

Abstract

The systematic position of the species in genus Avena L. still remains disputable among researchers. Comparative analysis of the whole specific diversity of oats was incited by the profound interest to the use of these forms in taxonomy and breeding practice, enforces by the late development of plant immunological, biochemical and other researches. Further search for taxonomy and utilization of new oat breeding sources is one of the objectives pursued by Vavilov Institute of Plant Industry (VIR) in studying its global germplasm collections (Loskutov 2000; 2001; 2002; 2003; Loskutov et al. 2001). The research presents the field results of studying (1988-2001), about 3000 accessions of 26 oat species with different ploidy level. Complex study of specific diversity and analysis of geographic distribution of the habitats of oat forms and species confirmed that the centre of origin of Avena L. lies in the western part of the Mediterranean region, while the secondary centre of formation of Avena species and origin of cultivated oat (A.sativa) is situated within the Asia Minor centre of crop origin. The analysis of intraspecific diversity helped to identify centres of morphogenesis for all cultivated oat species. The centre for the diploid sp. A.strigosa is Spain and Portugal, for the naked forms A.nuda L. UK, for the tetraploid species A.abyssinica it is Ethiopia, for the hexaploid species A.byzantina Algeria and Morocco, for the hulled forms of A.sativa Iran, Georgia and Russia (Tatarstan), and for its hull-less forms Mongolia and China. A revised taxonomic system for the species in the genus Avena based upon the degree of relationship with hexaploid species has been developed. We have divided this genus into two subgenera, subgen. Avenastrum and a typical subgen. Avena which is subdivided into Aristulatae Malz. ? Denticulatae Malz. Such division according to the characters of the lemma tip - biaristulate or Aristulatae and bidentate or Denticulatae. The study was targeted at morhpological characterization, agronomic traits and resistance to the most widespread diseases: crown and stem rusts, powdery mildew, Helminthosporium leaf blotch, Septoria blight, Mirothecium necrotic mottle and BYDV. Representative collection of all species has been analyzed for groat protein content - amino acid and groat oil content - fatty acid content. The study representative set of accessions of genus Avena L. species with different ploidy levels helped to determine intraspecific diversity in all characters. A majority of identified sources may be directly involved in the breeding for disease resistance, agronomic traits and grain quality. Loskutov I.G. 2000. Proc.6-th Inter. Oat Conference, 248-253; Loskutov I.G. 2001. Euphytica 117: 125-131; Loskutov I.G. 2002. Oat Newsletter, v.48; Loskutov I.G. 2003. Report of ECP/GR Cereals Network, 1-st meeting, Armenia, IBPGR; Loskutov et al. 2001. Oat Newsletter, v.47.