In vitro clonal propagation of ornamental foliage Aglaonema commutatum Schott

Abstract

The study entitled "In vitro clonal propagation of ornamental foliage Aglaonema commutatum Schott." was conducted at the Department of Floriculture and Landscaping, College of Agriculture, Vellayani, Thiruvananthapuram, during the period 2024-2025. The primary objective was to standardize the in vitro clonal propagation protocol of two high-value Aglaonema cultivars. The study focused on the standardization of in vitro propagation protocols for two commercially important cultivars of Aglaonema commutatum ‘Silver Queen’ and ‘Red Star’, with special emphasis on surface sterilization, culture establishment, shoot multiplication, in vitro rooting, and ex vitro establishment. This study was conducted to address the critical need for a reliable micropropagation method to facilitate rapid and large-scale multiplication of elite Aglaonema cultivars. Nine different sterilization treatments involving varied concentrations (0.1%, 0.5%, 1.0%) and durations (5 or 10 minutes) of mercuric chloride (HgCl₂), with or without a 70% ethanol pre-treatment, were tested. Complete explant survival (1.00) was achieved in treatments such as, T2, T4, T5, T7, T8 and T9 (Mercuric chloride 1.0 % for 5 minutes, T1 + 70 % ethyl alcohol, T2 + 70 % ethyl alcohol, Mercuric chloride 0.5 % for 5 minutes + 70 % ethyl alcohol, Mercuric chloride 0.1% for 5 minutes + 70 % ethyl alcohol, Mercuric chloride 0.1 % for 5 minutes) for both cultivars, while treatments T3 and T6 (1.0% HgCl₂ for 10 minutes, T3 + 70 % ethyl alcohol) resulted in total mortality, indicating phytotoxicity at higher exposure. The most effective decontamination was observed in treatments T7, T8, and T9 (Mercuric chloride 0.5 % for 5 minutes + 70 % ethyl alcohol, Mercuric chloride 0.1% for 5 minutes + 70 % ethyl alcohol, Mercuric chloride 0.1 % for 5 minutes), each recording 100% contamination-free cultures. These results confirm that moderate to low HgCl₂ concentrations combined with ethanol pre-treatment effectively balance sterility and tissue viability. Among the 23 treatment combinations (T0-T22) tested, treatments T1 and T22 (BA 2.0 mgL-1, BA 4 mgL-1 + NAA 2 mgL-1) were superior, achieving 100% survival and the most rapid culture establishment across both cultivars. Notably, ‘Red Star’ responded quicker under TDZ treatments (e.g., TDZ 1.0 mgL-1, TDZ 1.0 mgL-1 + NAA 0.1 mgL-1),

while ‘Silver Queen’ exhibited faster initiation in BA + NAA combinations (T22). Shoot initiation was significantly enhanced in treatments T1 and T22 BA 2.0 mgL-1,BA 4 mgL-1+ NAA 2 mgL-1), with T1 showing the highest shoot count per explant (3.00 in ‘Silver Queen’ and 2.67 in ‘Red Star’), as well as the earliest first leaf emergence. These results underscore the importance of cytokinin-auxin synergy (BA+NAA) for efficient shoot organogenesis. Early shoot emergence was observed under T16 (TDZ 2.0 mgL-1+ NAA 0.5 mgL-1 - 17.33 days in ‘Silver Queen’) and T14 (TDZ 1.0 mgL-1 + NAA 0.5 mgL-1- 21.67 days in ‘Red Star’). Shoot elongation was most pronounced in T9 and T10 (BA 4.0 mgL-1+ NAA 0.1 mgL-1, BA 4.0 mgL-1+ NAA 0.5 mgL-1) for ‘Silver Queen’, and T1 and T10 (BA 2.0 mgL-1, BA 4.0 mgL-1+ NAA 0.5 mgL-1) for ‘Red Star’, reflecting the favorable influence of hormonal balance in these treatments. Leaf formation remained limited, with T1 and T2 showing slight advantages across both cultivars. Root initiation varied significantly between treatments. T3 and T4 (IBA 2 mgL-1 and NAA 0.25 mgL-1) showed consistent and early rooting in both cultivars, with ‘Red Star’ demonstrating better rooting efficiency, producing up to 6 roots per explant and root lengths of 7.2 cm. In contrast, ‘Silver Queen’ exhibited fewer and shorter roots. Treatments T1, T7, and T9 (IBA 0.5 mgL-1, NAA 2 mgL-1, IAA 1 mgL-1) consistently failed to induce rooting, indicating suboptimal auxin conditions. Among the four substrates tested, vermiculite, perlite, sand, and LECA balls, vermiculite was the most effective for both survival and growth of plantlets. LECA balls failed, indicating their unsuitability for acclimatization. Though differences in ex vitro responses were not statistically significant, vermiculite provided the most promising environment for early plantlet establishment. This study successfully established an efficient, reproducible in vitro propagation protocol for Aglaonema commutatum cultivars ‘Silver Queen’ and ‘Red Star’. Treatment T8, T9 (Mercuric chloride 0.1% for 5 minutes + 70 % ethyl alcohol and Mercuric chloride 0.1 % for 5 minutes) for surface sterilization, T1 and T22 (T1 - BA 2.0 mgL-1 and T22 - BA 4 mgL-1+ NAA 2 mgL-1) for culture establishment, T1 (BA 2 mgL-1 + NAA 0.5 mgL-1) emerged as the most effective for shoot multiplication and organogenesis, while T3 and T4