Effect of Stock Plant Growing Medium and Density upon a Cutting Propagation System for Tea Tree, Melaleuca alternifolia

Abstract

To offer a viable alternative to seedling deployment of tea tree, clones will require the development of an efficient, robust, and vegetative propagation system for the large number of plants needed for plantations (i.e., typically 33,000 plants/ha). This study investigated the productivity of an intensive management system for tea tree stock plants and rooted cuttings grown in a subtropical environment (Lismore, NSW, Australia). Three stock plant densities (30, 100, and 200 plants/m2) were tested in coir and potting mix media (consisting of peat+perlite+vermiculite), with 11 settings of cuttings undertaken between April 2019 and March 2020. All stock plants in each media type survived 11 harvests and remained productive; however after 13 months, many plants in the coir media, appeared chlorotic and showed symptoms of iron deficiency. Rooting and cutting survival rates using the mini cutting technique were high, ranging from a maximum mean monthly setting value of 87.7% ± 4 at 84 days post-setting in potting mix, to a minimum of 80.4% ± 3.7 in coir. The most productive treatment was at high stock plant density in potting mix which had the potential to produce 13,440 plants/year/m2. Overall coir appeared less productive, but the pattern of difference among treatments was similar. For the highest system productivity, it is recommended to grow stock plants in potting mix at high densities and modulate temperatures to between 18 °C and 28 °C. Late spring and early summer were the best time for harvesting and setting tea tree mini cuttings in the subtropics.

Strigolactone analogue GR24 reduces axillary bud out break and growth in tea tree, Melaleuca alternifolia (Maiden & Betche) Cheel

“…Scion from a clonal line was set in January 2020 using the mini cutting technique with intact apical buds (Lowe et al, 2019). The GR24 experiments were conducted 5 months postsetting when cuttings had rooted and possessed a single main stem with no visi ble axillary buds detectable with a 10x magnification hand lens (Fig.…”

“…Tea tree tip cuttings with single stem architecture suitable for mechan ical planting can be produced if the apical bud remains intact (Lowe et al, 2019). Nodal cuttings (apical tips removed) are preferred to tip cuttings by some propagators for their robustness in the nursery but these tend to have a multistem habit which is unsuitable for machine planting as the "bushy" shoots get stuck in the delivery tubes of planters.…”