Variability of common wild oat (Avena fatua L.) in north-eastern Poland

Systematic studies on common wild oat (<i>Avena fatua</i> L.) in north-eastern Poland were based on 120 herbarian sheets and 2000 panicles collected for statistical studies. The majority of the material (70%) differed in respect to morphological features from the basic features accepted as species-specific in common keys of plants used in Poland (S z a f e r, 1919; S z a f e r et al., 1969). The differences referred mainly to the number of flowers in the spiklets, hairs of lower lemma and its callus, both as regards length of hairs and their distribution and colour. Basing on the results of foreign authors (M a l z e w, 1930; R o s h e w i t z, 1934; H e g i, 1965; S a v u l e s c u, 1972; T z v e l e v, 1974, 1976; K e m m e r et al., 1976) four basic varieties of <i>Avena fatua</i> L. were distinguished in the material: 1. var. <i>fatua</i> (= var. <i>pilosissima</i> S. F. Gray), 2. var. <i>intermedia</i> (Lestib.) Lej. et Court., 3. var. <i>glabrata</i> Peterm., 4. var. <i>vilis</i> (Wallr.) Hauskn. Statistical studies embraced 20 stations (fields with area of about 1ha). 100 panicles of <i>A. fatua </i>were randomly collected from each station. All four varieties were found at 14 stations, three varieties only were found at 4 stations, while at two stations only two varieties grew. None of the populations under study was one-variety only. Totally the material (stations 1 - 20) contained 29,6% of <i>A. fatua</i> var. <i>fatua</i> (= <i>pilosissima</i>), 28,4% of <i>A. fatua</i> var. <i>intermedia</i>, 22,4% of <i>A. fatua</i> var. <i>glabrata</i> and 19,6% of <i>A. fatua</i> var. <i>vilis</i>. The studies took into account only specimens classified as <i>A. fatua</i> L., disregarding hybrids and fatuoids. Knowledge on the distinguished varieties of common wild oat should contribute to the explanation of some doubts as to the distinction of its grains in seeding material. It may also prove useful in the chemical control of this dangerous weed.