THE EFFECT OF GA₃, ALAR AND CCC ON CITRUS CUTTINGS

Effects of GA₃ and Alar on growth characteristics and on flower formation were studied on cuttings of Citrus madurensis grown under temperate and tropical conditions.

Under both conditions GA₃ resulted in relatively low root weight but strongly increased shoot dry matter. With GA₃, elongation, growth and total dry matter were only promoted under temperate conditions. Leaf numbers were reduced, but the single leaf surface increased. GA₃-treated plants under temperate conditions had higher water consumption and transpiration rates but a better water use efficiency (transpiration ratio) than Alar-treated and control plants. Flowering was strongly reduced. Fruit volume was increased. There was little effect on seed weight and germination of seeds, but, on the average, seeds germinated earlier than those from the control plants.

Alar sprays reduced root, shoot and leaf dry matter. More, but smaller leaves were formed. Under temperate conditions, water consumption and transpiration rates were slightly reduced. More flowers were formed, particularly under tropical conditions. Fruit volume was slightly increased, but seed weights were strongly reduced and the germination time delayed.

CCC effects were examined only under tropical conditions and there they were very similar to those from Alar treatments.