Differential Effects of the Parental Photothermal Environment on Development of Dormancy in Caryopses of<i>Aegilops Kotschyi</i>

Abstract

Aegilops Kotschyi Boiss. plants produce three florets per spikelet (of which the terminal floret is commonly sterile) and exhibit physiological heterocarpy in the two caryopses which develop in each spikelet. Germinability of the basal caryopsis, but not of the upper one, was subject to environmental influences to which the parent plant was exposed during its development. Basal caryopses produced by plants grown at low temperature, or in 16-h photoperiods, were more dormant than when produced by plants grown at higher temperature, or in 8-h photo-periods. Germinability of the upper caryopses was equally high in all cases and independent of the parental environment. The photoperiod effects on germinability were exerted after anthesis. Mature weight of both basal and upper caryopses was higher when produced on plants grown at low temperature, or transferred from 16-h to 8-h photopenods at emergence of the flag leaf