Effects of Substrate and Hormone on Cutting Propagation of Rhododendron hainanense

Key words: 
• Rhododendron hainanense /
• rooting substrate /
• plant growth regulator /

Abstract: The annual semi-lignified branches of Rhododendron hainanense were selected as cuttings,and an orthogonal experiment was arranged for culture of the cuttings on different substratesto analyze the effects of treatment time and concentrations of IBA and NAA on the cutting propagation of R. hainanense in Substrate 1（ peat:coco coir∶ perlite = 1∶ 1∶ 1） and Substrate 2（ garden soil: coco coir∶ perlite = 1∶ 1∶ 1）,in order to screen the best treatment combination that improved rooting rate and the health of root system. The results showed that hormones had significant influence on rooting rate,of which IBA was the better hormone for root induction. Cuttings,when soaked in 600 mg·L^-1 IBA for 600 s and then inserted into the Substrate 2 produced the highest rooting rate（ up to 90. 0%） with the longest adventitious root being up to 2. 1 cm. Substrates had significant influence on the length of adventitious roots,Cuttings,when soaked in 600 mg·L^-1 NAA for 10 s and inserted into the Substrate 2,produced an rooting rate of up to 80. 0% with the longest adventitious roots of up to 3. 1 cm. All the results showed that cuttings improved the rooting rate and the health of root system effectively when soaked in 600 mg·L^-1 IBA for 600 s and inserted into the Substrate 2.