Production of the stunted oleander

Abstract EN

A trial was consummated at Orman Botanical Garden, Giza, Egypt throughout 2005/06 and 2006/07 seasons to find out the effects of foliar spraying with either 0, 50, 100 and 150 ppm of paclobutrazol (PP-333) or 0, 1000, 2000 and 3000 ppm of cycocel (ccc) for three times with three weeks interval, pinching treatment and their interaction on growth, flowering and chemical composition of 6-months-old Nerium oleander L.

transplants grown in 30-cm-diameter black polyethylene bags.

The obtained results exhibited that plant height (cm), stem diameter (cm), branch and leaf No./plant, leaf area (cm2), root length (cm), as well as the fresh and dry weights of aerial parts and shoots (g) were significantly decreased in both non pinched and pinched plants as a result of spraying with the various levels of either PP-333 or ccc in the two seasons.

The best dwarfing result was found due to spraying with 100 ppm of PP-333 and 2000 ppm of ccc, as such two treatments declined the size of treated plants to the optimum size suitable for commercial marketing.

Likely, pinching treatment significantly reduced all vegetative and root growth parameters with the exception of branch No./plant character, that was increased in pinched plants with significant differences when compared to the non-pinched ones in both seasons.

Moreover, all concentrations of both retardants, as well as pinching treatment delayed flowering and significantly reduced all flowering measurements in both non-pinched and pinched plants except for inflorescence No./plant trait, which was in the same rank for non-pinched and pinched plants.

However, the low level of both PP-333 and ccc (50 and 1000 ppm, respectively) significantly increased number of florets/inflorescence in the two seasons.

So, the plants under these two treatments were more attractive.

The content of chlorophyll a, b, carotenoids and indoles (mg/g F.W.) was progressively decreased in the leaves of both non-pinched and pinched plants with elevating of either PP-333 or ccc levels, while phenols content was gradually increased.

Paclobutrazol at the rate of 50 ppm, on the other hand, raised the content of chlorophyll a and b in the leaves of non-pinched and pinched plants.

However, pinching treatment induced a significant reduction in all previous constituents.

In brief, to obtain a good display of flowering pot Nerium oleander L.

plants with optimum vegetative and flowering characteristics from the commercial point of view, it is recommended to spray the foliage of non-pinched transplants with either low or medium concentrations of PP-333 (50 and 100 ppm, respectively) or ccc (1000 and 2000 ppm, respectively), and the pinched ones with the only low concentration of either PP-333 (50 ppm) or ccc (1000 ppm), for 3 times with 3 weeks interval.