SPONTANEOUS CROSSING BETWEEN DIPLOID AND TETRAPLOID SINAPIS ALBA

Abstract

ECENTLY, M ~~N T Z I N G (1948) has shown that tetraploid rye, when R grown in yield tests together with a diploid standard variety, is markedly less fertile and yields less tliari when the same tetraploid is grown by itself, isolated by distance from any diploid. Evidently, in tests where both types grow on adjacent plots the tetraploid cannot develop tlie whole of its capability of seed production, since a large number of its egg-cells are fertilized by pollen from the diploid, resulting in triploid and abortive embryos.