The influence of the origin of the mother plant on yield and germination of their caryopses in Aegilops ovata.

Dispersal units of Aegilops ovata contain in their spikelets caryopses differing in morphology, weight and germinability according to their position in the spikelets. Plants originating from caryopses of the diverse orders were grown under various photo- and thermoperiodic conditions, and the caryopses harvested germinated under uniform conditions. Under all conditions tested, the relative difference in weight between the caryopses of the various orders was not affected. But plants grown under long days and/or low temperatures produced heavier caryopses than plants grown under short days and/or high temperatures respectively. There was a positive correlation between weight and germinability in caryopses of the various orders derived from one mother plant, and a reverse correlation in caryopses formed on mother plants grown under low and high temperatures. When mother plants arising from various orders of caryopses were grown under long days and low temperatures, they produced caryopses of different germinability, showing that the origin of the mother plant may affect the germination qualities of its offspring. The implications of these results are discussed.