Fatuoids or False Wild Oats

Abstract

IN a study of the segregates of a cross made between the tetraploid species Avena barbata and the diploid species A. brevis, certain points of interest have emerged concerning the behaviour of the characters which in the hexaploid species Avena sativa constitute the fatuoid complex. In the latter species, when a fatuoid is crossed with normal or cultivated type of grain the fatuoid complex behaves as a partial recessive and in inheritance gives simple Mendelian segregation; there is no break-up of the complex, and no crossing-over takes place. In the Avena barbata Avena brevis cross, however, these same associated characters, of articulation, basal pubescence, and awn, behave in the F₁ as partial dominants, particularly so in respect of the character of the articulation of the grain. Moreover, in the later generations there is a break-up of the fatuoid complex, and cross-over types are produced. Segregates have appeared in this cross in which the basal articulation and basal pubescence characters of the A. barbata parent occur in association with the awn and grain-apex of A. brevis type, and conversely segregates with typical A. barbata awns and the glabrous and normal or solidified base of A. brevis.