EFFETS DE QUELQUES RETARDANTS DE CROISSANCE ET DE L’ACIDE GIBBERELLIQUE SUR LA RESISTANCE AU FROID DE LA LUZERNE (MEDICAGO SATIVA)

Abstract

The enhancement of frost hardiness of alfalfa by treatment with growth retardants in the field remains uncertain and could depend on the hormonal status of the plant, conditioned by photoperiod and temperature. Timing of treatment in the field is therefore important and difficult to pinpoint, thus resulting in variable effects from year to year on growth, survival and yields of the plants, whatever the soil type used. Alar and phosphon were superior to CCC in their effects on growth, winter survival and yield, and seemed more promising than the latter. Gibberellic acid and CCC had opposite actions and CCC effects were overcome by gibberellic acid.