Some remarks on the polycross test method applied in grasses

Although the polycross methods developed by Tysdal, Frandsen and Wellensiek are mostly considered, also by the authors themselves, to be practically the same, those applied by Tysdal and Frandsen essentially differ from the method of Wellensiek. The former authors try to find combining ability while the latter attempts to detect genetic differences. Imperfections in the logical conception, combined with practical difficulties which have to be faced, while carrying out an ideal program, are often responsible for a less successful result of the polycross method in looking for the best combining ability. There are no such imperfections in the conception of Wellensiek's method. Possibilities are being explored to develop a method ensuring a good determination of combining ability of a grass clone by means of an I₁-generation derived from one individual through self-pollination.