Jasmine is an important commercial flower crop occupying larger area among the traditional flower crops grown in Tamil Nadu. This crop has a main flowering season during March to October and an off-season from November to February. During this off-season, flowering is very poor or there is no flowering at all. In recent years, growth regulators are valuable tools in floriculture for manipulating growth and flowering of many crops and hence and attempt has been made to induce flowering during off season using growth regulators in Jasmine. The treatment comprises of both two growth promoting substances viz., NAA and GA3 and two growth retardants (Cycocel and Maleic Hydrazide). The data on vegetative parameters viz., plant height, number of primary shoots, number of nodes, intermodal length, number of leaves and flowering parameters viz., days taken for flowering, duration of flowering, flower yield and hundred flower weight were recorded. Results of the experiment revealed significant differences among the growth regulator treatments. Among the various treatments, application of NAA @ 75 ppm (T6) recorded the highest plant height (130.6 cm and 178.5 cm), number of primary shoots (21.68 and 35.68), number of nodes (9.86 and 15.89 cm) and number of leaves (1250.0 and 2689.5) at 90 and 180 DAP respectively. Earliness in flowering (26.38 DAP) and maximum duration of flowering (171.00 days) were noticed in T3(GA3@ 150 ppm). From the above studies, it is inferred that application of GA3 @ 150 ppm or NAA @ 75 ppm enhanced growth and higher flower yield in Jasminum sambac.
