My Research Findings in Avena

Abstract

This chapter occupies the main part of the book. It describes a series of studies undertaken over the past 48 years. During that time a major effort was devoted to series Eubarbatae. In this series, the length of the bristles at the tip of the lemma was used to separate diploids from tetraploids in mixed populations and herbarium material. Accurate identification of the diploid and tetraploid made possible to determine the geographic distribution and the ecological preferences of each of them. Cytogenetic analyses of their triploid hybrids indicated that the diploid form A. strigosa is the progenitor of the tetraploid A. barbata. It was shown further that this tetraploid emerged through autopolyploidy and its bivalent pairing at meiosis is under control of a single gene. Two species of this series were discovered during the last 50 years. The events leading to their discovery are briefly described. Section Denticulatae contains among others the common oat and its wild forms, all of which share the same genome, commonly designated ACD. This designation is based on comparisons of chromosome morphology and chromosome in situ hybridizations. These types of evidence are in sharp contrast to hybridization-based analyses of chromosome pairing. It was concluded that corroboration of this genome labeling must await the discovery of the diploid progenitors of the polyplois species of section Denticulatae. Over the last 50 years five new species of section Denticulatae were discovered, one of which was the tetraploid progenitor of the common oat and its wild forms. The way by which these five species were discovered is briefly described. The longest project undertaken was an attempt to domesticate the protein-ich wild tetraploid A. magna. This species contains accessions with protein content as high as 27 %. While transferral of that protein content to the common oat is impossible because of differences in chromosome numbers, domestication of A. magna seemed to be a feasible alternative way to exploit that protein content. After five hybridization cycles between the common oat and A. magna we possess domesticated tetraploid lines that are indistinguishable from the common oat and have 25–26 % protein.