Effect of auxin and cytokinin on the vegetative propagation of cabbage (Brassica oleracea var. capitata L.)

Abstract

To determine the value of auxin and cytokinin in the vegetative propagation of cabbage, three types of cuttings; leaf, root and leaf-bud were treated with aqueous solutions of Indole-3-Butyric Acid (IBA) and 6-Furfurylaminopurine (Kinetin) alone and in combinations. IBA stimulated root formation and the stimulation was reflected in earliness of rooting, a larger number of roots per cutting and higher percentage of cuttings producing roots. Kinetin delayed root formation, gave fewer roots per cutting and lower percentage of rooted cuttings. Optimum concentration of IBA alone was between 25 and 50 ppm. Cuttings treated with both IBA and Kinetin produced more roots per cutting than those treated with IBA alone. At a constant level (35 ppm) of IBA, the average number of roots increased gradually as the concentration of Kinetin was raised from 0 to 50 ppm. The total number of cuttings that produced roots was almost the same in treatments having either IBA or IBA with Kinetin but in all cases much higher than control. Leaf-bud cuttings did not form adventitious buds until the axillary buds were removed. After removal of axillary buds, many of the cuttings started to form adventitious buds within a week, although some took longer. The earliest bud produced by a leaf cutting was observed 32 days after hormone treatment. However, the majority of leaf cuttings started bud formation in 50 days. Treatments having IBA or IBA plus Kinetin showed no significant difference in the number of adventitious buds. Kinetin alone (25 ppm) produced a significantly lower number of buds than all other treatments including the control. Number of buds was not directly correlated with the number of roots nor earliness of root formation. However, a good root system was found essential for survival and subsequent bud formation..