Full Length Research Paper

Effects of indol–3-butyric acid (IBA), plant growth promoting rhizobacteria (PGPR) and carbohydrates on rooting of hardwood cutting of MM106 Apple rootstock

Halil Karakurt*, Rafet Aslantas, Gursel Ozkan and Muharrem Guleryuz

Department of Horticulture, Faculty of Agriculture, Ataturk University, 25240, Erzurum, Turkey.

*Corresponding author. E-mail: halilkarakurt@yahoo.com. Fax: (90)(442)2311541. Tel: (90)(442) 2312641.

Accepted 14 January, 2009

   Abstract

This investigation was conducted to evaluate the effects of a range of indole-3-butyric acid (IBA) concentrations (1000, 2000 and 4000 ppm), two strains of Agrobacterium rubi (A-18) and Bacillus subtilis (OSU-142) and four carbohydrates (Glucose, Sucrose, Sorbitol and Mannitol) alone, in combination with two and three treatments on the rooting capacity of the hardwood cuttings of MM106 apple rootstock in greenhouse conditions. No rooting was obtained from control treatments but only low callus formation (10%). Single treatments did not induce rooting, except IBA-1000 ppm, OSU-142 and A-18, but induced better callus formation (20%) compared to control. Double and the three combinations were more successful in terms of rooting and callus formation. A-18+sorbitol, OSU-142+sorbitol+IBA-2000, A-18+sorbitol+IBA-2000 and A-18+sorbitol+IBA-4000 treatments were obtained from the highest rooting formation (30%) and OSU-142+sorbitol treatment had the highest callus rate (70%), that may be a precursor of adventitious root formation. IBA-1000 ppm treatment had the highest adventitious root number (16.5). A-18 treatment had the highest average adventitious root thickness (1.61 mm). The results indicate that double and triple combination of IBA, bacteria and carbohydrates are more effective in increasing rooting capacity and more quality rooting when compared to control, or carbohydrate, IBA and bacteria alone.

Key words: Apple rootstock, hardwood cutting, IBA, bacteria, carbohydrate.