Effects of growth regulator naa and substrate on rooting of diamond frost trees (euphorbia hypericifolia l.) cuttings in the nursery stage in Ho Chi Minh city

Abstract

The Diamond Frost plant (Euphorbia hypericifolia L.,1753) is classified as a herbaceous species characterized by its compact form and white inflorescences, making it highly suitable for cultivation in pots for ornamental applications on balconies. This study aimed to evaluate the effects of the growth regulator naphthaleneacetic acid (NAA) and various substrate compositions on the rooting of Diamond Frost cuttings during the nursery phase. A two-factor experiment was conducted using a completely randomized design (CRD) with three replications, incorporating five levels of NAA concentrations and four distinct substrate compositions. The results identified the optimal NAA and substrate combinations for propagating Diamond Frost seedlings through cuttings in a polyhouse under the climatic conditions of Ho Chi Minh City, with combinations included NAA treatments at concentrations of 1,500 ppm, 3,000 ppm, and 4,500 ppm, paired with substrates consisting of 70% coconut fiber, 20% vermicompost, and 10% rice husk ash; 30% coconut fiber, 30% loamy soil, 30% vermicompost, and 10% rice husk ash; or 35% coconut fiber, 35% loamy soil, 20% vermicompost, and 10% rice husk ash. The findings indicated that the optimal protocol for the development of Diamond Frost cuttings involved treating cuttings with 1,500 ppm NAA and using a substrate mix of 35% coconut fiber, 35% loamy soil, 20% vermicompost, and 10% rice husk ash. This combination achieved a rooting rate of 84.67%, with an average of 11.4 roots per cutting, an average root length of 6.2 cm, and a transplant success rate of 82.0%. The profit generated was 4,205 VND per pot.