Effects of an organic seaweed growth regulator to enhance root growth parameters in pot-cultured Erica verticillata Bergius (Ericaceae) in developing a production schedule to support future reintroductions into the wild

Abstract

Erica verticillata Bergius (Ericacea) is a South African indigenous species which is classified as extinct in the wild. Current cultivation practices have focused on reintroducing the coastal fynbos shrub into its original habitat. The use of organic seaweed growth regulators on indigenous fynbos species is unknown. The 18-week study tested two different formulations of a commercial organic seaweed growth regulator at varied dosages on root growth parameters of potted Erica plants. Ten replicates of plant growth regulator treatments were used. Treatments of 0 (control), 50, 100, 200, 300 mL liquid stock solution and 1/4, 1/2, 1 and 2 solid disks plant-1 were applied to rooted cuttings of ±3 cm in height. The study aimed to develop a production schedule for growing pot-cultured E. verticillata. Plants treated with the highest liquid treatment of 300 mL, 1/4 disk and the control treatment induced the highest wet weights. Liquid treatments of 50, 100, 200 mL and 1/4, 1 and 2 disks were all similar in increasing dry root weight compared to the control (0). An application of (100-200 mL) liquid and 1/2 solid disk treatments were most significant in the postharvest root lengths compared to the other treatments at 18 weeks postharvest. Liquid treatments had better results on the root length than did disks. It is recommended that an application of 100-200 mL liquid of organic seaweed growth regulator per plant be used in growing pot-grown E. verticillata. This might enhance cultivation protocols of other indigenous fynbos species with similar growing requirements suitable for container growing. The production of E. verticillata has the potential to support the effective re-establishment and conservation in the wild.