Although overhead mist revolutionized the propagation industry, it does suffer from potential drawbacks that include the application of large volumes of water, potentially unsanitary conditions, irregular misting coverage, and leaching of foliar nutrients. We explored the feasibility of submist as an alternative as it might avoid these problems by applying water exclusively from below the cutting, which is inserted basally into an enclosed rooting chamber. We propagated cuttings of korean lilac (Syringa pubescens ssp. patula) and inkberry (Ilex glabra) using both overhead mist and submist to compare effectiveness of the systems. Cuttings of korean lilac were wounded and dipped basally into 8000 mg·L−1 of the potassium salt of indole-3-butyric acid (K-IBA), and those in the overhead mist systems were inserted into coarse perlite. Cuttings of inkberry were wounded and treated with 5000 mg·L−1 K-IBA, and those in the overhead mist systems were inserted into 50:50 peat:perlite (by vol). Cuttings of korean lilac in the submist systems produced more than twice as many roots as cuttings in the overhead mist systems, with roots more than 2.6 times the length. Similarly, cuttings of inkberry in the submist systems produced more than three times the root counts and root lengths as cuttings in the overhead mist systems. For korean lilac, root dry weights averaged 58 mg for cuttings in the submist system, compared with only 18 mg among cuttings receiving overhead mist. Likewise, root dry weights averaged 70 and 7 mg for cuttings of inkberry propagated by submist and overhead mist, respectively. Rooted cuttings of korean lilac transplanted well into a soilless substrate, where they more than tripled their root biomass to 218 mg (vs. 59 mg for cuttings transplanted from overhead mist). We did not evaluate transplant performance of inkberry. Our results show that submist systems might merit consideration for the propagation of woody plants by leafy stem cuttings.
Bryan J. Peterson, Stephanie E. Burnett, and Olivia Sanchez
Jason D. Lattier and Ryan N. Contreras
Lilacs (Syringa sp.) are a group of ornamental trees and shrubs in the Oleaceae composed of 22–30 species from two centers of diversity: the highlands of East Asia and the Balkan-Carpathian region of Europe. There are six series within the genus Syringa: Pubescentes, Villosae, Ligustrae, Ligustrina, Pinnatifoliae, and Syringa. Intraspecific and interspecific hybridization are proven methods for cultivar development. However, reports of interseries hybridization are rare and limited to crosses among taxa in series Syringa and Pinnatifoliae. Although hundreds of lilac cultivars have been introduced, fertility and cross-compatibility have yet to be formally investigated. Over 3 years, a cross-compatibility study was performed using cultivars and species of shrub-form lilacs in series Syringa, Pubescentes, and Villosae. A total of 114 combinations were performed at an average of 243 ± 27 flowers pollinated per combination. For each combination, we recorded the number of inflorescences and flowers pollinated as well as number of capsules, seed, seedlings germinated, and albino seedlings. Fruit and seed were produced from interseries crosses, but no seedlings were recovered. A total of 2177 viable seedlings were recovered from interspecific and intraspecific combinations in series Syringa, Pubescentes, and Villosae. Albino progeny were produced only from crosses with Syringa pubescens ssp. patula ‘Miss Kim’. In vitro germination was attempted on 161 seed from interseries crosses, resulting in three germinations from S. pubescens Bloomerang® x Syringa vulgaris ‘Ludwig Spaeth’. None survived, yet cotyledons produced callus for future efforts to induce embryogenic shoots. This study is a comprehensive investigation of lilac hybridization, and the knowledge gained will aid future efforts in lilac cultivar development.
Stephanie E. Burnett, Bryan J. Peterson, and Marjorie Peronto
. In previous research, manchurian lilac ( Syringa pubescens ssp. patula ‘Miss Kim’) had more roots and longer roots when it was propagated in submist ( Sanchez et al., 2020 ). Manchurian lilac plants are often challenging to propagate if cuttings