A correlation of nuclear DNA content and thin-layer chromatographic patterns in resolving genome relationships in Avena

Abstract

Relative amounts of nuclear deoxyribonucleic acid (DNA) from telophase root tip nuclei and thin-layer chromatographic patterns of alcohol-soluble compounds from dry leaves were determined for seven diploids: Avena clauda, A. pilosa, A. ventricosa, A. strigosa, A. hirtula, A. wiestii, A. longiglumis; four tetraploids: A. barbata, A. magna, A. abyssinica, A. vaviloviana; and four hexaploids: A. sterilis, A. fatua, A. byzantina, and A. sativa, in order to elucidate species relationships. Variation in nuclear DNA content was correlated with differences in genomic constitution; a few exceptions are considered to reflect chromosomal polymorphism. The average DNA value of the hexaploid species approximated the sum of the DNA value for A. magna and the theoretical value of the B genome. Chromatographic patterns showed distinct variations between species but little correlation between number of compounds and DNA content. Chromatographic patterns of hexaploids showed close similarity with those of diploids and tetraploids, except species with modified C genomes (A. clauda, A. pilosa, A. ventricosa) and A. longiglumis. It is considered that A. clauda, A. pilosa, A. ventricosa, and A. longiglumis did not participate in the evolution of polyploid taxa. From their chromatographic profiles, A. wiestii, A. abyssinica, A. vaviloviana, and A. byzantina are very closely related. Both A. magna and the AABB tetraploid species appear to share two genomes in common with the hexaploids. Hence, the genomic constitutions AADD and AABBDD have been proposed for A. magna and the hexaploids, respectively. Six compounds from ethanol leaf extracts of A. sativa were identified as three apigenins, luteolin, ferulic acid, and p-coumaric acid.