Effect of the K-IBA Foliar Application on the Rooting of Geraldton Waxflower ?Mars? and ?Early Nir? Semi-hardwood Cuttings

This study was carried out to improve the rooting percentage and rootstock quality of Chamelaucium uncinatum 'Mars' and 'Early Nir' semi-hardwood cuttings with K-IBA total immersion or as a foliar spray application. In the total immersion case, all cuttings were immersed in K-IBA 500, 1,000, 2,000, and 4,000 mg center dot L-1 solutions for 30 seconds or for 1-4 minutes, after which they were stuck into the media. The foliar spray was applied with a solution at the same concentration to the extent that the solution dripped down from the leaf surface at one-week intervals over one, two, four, or eight weeks after cutting. Total immersion with the K-IBA 2,000 and 4,000 mg center dot L-1 solutions for two minutes increased the rooting ratio by more than 40% for waxflower 'Mars' cuttings in May. The K-IBA 500 and 1,000 mg center dot L-1 foliar spray applications also increased the rooting percentage by more than 50% for cuttings in Septembers. With regard to 'Early Nir' cutting propagation in October, the survival ratio and rooting percentage increased when immersed in the K-IBA solution, showing no adverse effects even with increasing the concentration and immersion time. The rooting percentage exceeded 50% when immersed for two and four minutes at 4,000 mg center dot L-1. The K-IBA foliar application also improved the survival percentage and rooting ratio, but the rooting percentage was less than 40% and decreased as the spray time was increased. From the above results, foliar spray drip down with K-IBA 500 and 1,000 mg center dot L-1 solutions for 'Mars' in September and total immersion in the K-IBA 4,000 mg center dot L-1 solution for two or four minutes with 'Early Nir' in October can be used to increase the cutting propagation efficiency of semi-hardwood cuttings, respectively.

Automated summary

This study aimed to enhance the rooting percentage and rootstock quality of Chamelaucium uncinatum 'Mars' and 'Early Nir' semi-hardwood cuttings through total immersion or foliar spray application of K-IBA. Results showed that total immersion in 2,000 and 4,000 mg/L K-IBA solutions for two minutes significantly increased rooting ratio for 'Mars' in May, while foliar spray with 500 and 1,000 mg/L K-IBA solutions increased rooting percentage for cuttings in September. For 'Early Nir' in October, immersion in K-IBA solution improved survival ratio and rooting percentage, with the best results obtained at 4,000 mg/L for two and four minutes. However, foliar application decreased rooting percentage with increasing spray time. Overall, foliar spray with 500 and 1,000 mg/L K-IBA solutions in September and total immersion in 4,000 mg/L K-IBA solution for two or four minutes in October can be recommended to improve the cutting propagation efficiency of semi-hardwood cuttings.