Effect of growth regulators on rooting of cuttings and layers in Jasmine (Jasminum auriculatum Vahl.)

Abstract

Systematic studies were carried out to standardise various aspects of asexual propagation in jasmine through cutting and layering. For propagation studies using cuttings, semihard wood cuttings of jasminum auriculatum and Jasminum grandiflorum were treated with IBA and NAA each at 2000, 3000 and 4000 ppm concentrations and planted under mist and open conditions. The results revealed that all the auxin treatments particularly IBA were superior to control with regard to rooting percentage. Other root growth parameters such as number, length, fresh weight and dry matter production of roots were also maximum with IBA treatments. However, in Jasminum auriculatum, the effect of growth regulators was not statistically significant and this may be attributed to the shy rooting behaviour of this species due to some endogenous inhibitors. Regardless of the growth regulator treatments mist had profound influence on root growth as well as vegetative growth parameters in both the species of Jasminum studied. To find out the effect of growth regulators and season on rooting of layers, layering was done at monthly intervals with ISA and NAA each at a concentration of 100 and 250 ppm. The results indicated that all the growth regulator treatments were superior to control with regard to rooting percentage, number, length, fresh weight and dry matter production of roots. Study on seasonal effect on success of layering has clearly shown that layering should be done during the rainy season particularly from June to September for getting maximum success. However, further studies to find out the role of inhibitory substances present in the shoots which cause failure of rooting of cuttings and layers may perhaps yield valuable results.