Endogenous Carbohydrate Content of the Cutting Positions at Time of Severance and IBA Concentration Influence Rooting of Rosa hybrida Rootstocks

Abstract

Insufficient rooting of cuttings may result in economic losses and limit the use of some rootstocks. Present study was aimed at evaluating the effect of cutting position (top, middle and bottom) and Indole-3-butyric acid (IBA) concentrations (0%, 0.2%, 0.4% and 0.6%) on rooting of Rosa Progress and Natal Briar cuttings. Carbohydrate content of the cutting positions at the time of severance was determined. The experiment was factorial in a completely randomized design (CRD). The root and shoot growth parameters as well as carbohydrate levels in the leaves increased acropetally in both rootstocks. Indole-3-butyric acid (IBA) treatment enhanced root number, total root length and root fresh weight of both rootstocks. Among the IBA treated cuttings 0.4% had higher rooting and survival percentage than 0.2% in Natal Briar. Rosa Progress exhibited higher root number, shooting and survival percentage than Natal Briar though carbohydrate content in the original leaf at the time of severance was low. Carbohydrate content in the leaf of both rootstocks was higher than in the stem and this presumably ensured continuous supply of carbohydrates to the stem base during the rooting process. Auxin (IBA) treatment and high endogenous carbohydrate in the original leaf at the time of cutting severance enhanced rooting especially in Natal Briar.