Background: Most orchid species in the Dendrobium genus are epiphytic. Dendrobium orchid (Dendrobium nobile L.) var. Sonia is a non-woody epiphytic orchid that bears a beautiful purple-coloured flower and grows in soilless medium. Dendrobium can be propagated vegetatively through divisions or Keikis. But this propagation method is extremely slow. Micropropagation is most suitable method for multiplication of dendrobium orchids. Surface sterilization is an important step in the preparation of vigorous and viable explants in micropropagation. Most of the surface contaminants can be abolished by surface sterilization with a suitable sterilizing agent. The aim of the investigation is to present an effective disinfection method for the aseptic culture of Dendrobium var. Sonia by using nodal segments.&nbsp; 
 
Methods: In the present investigation, two sterilant were employed namely mercuric chloride (HgCl2) and sodium hypochlorite (NaOCl) at different concentrations and durations. A total of nine combinations were tried for treating nodal explants in this investigation during 2022-2023. Explants were surface sterilized with 70% ethanol for 5 minutes followed by 3 to 4 washes with sterile distilled water. Thereafter, the explants were subjected to different surface sterilization treatments to establish contamination free cultures. 
 
Result: The study revealed that among the 9 treatments, minimum contamination (30.40%) was recorded in 0.1% HgCl2 for 10 minutes which helps in the maximum establishment of healthy culture (69.60%). Whereas, the lowest result for establishment was found in autoclaved distilled water with maximum contamination (100%). Maximum explant mortality (20.80%) due to sterilant was observed in NaOCl (2%) for 20 minutes.

Efficient Surface Sterilant for Establishment of Dendrobium in vitro Culture

<div>Background: Dendrobiums are most popular high value cut flowers which require special attention during cultivation. In Assam, Dendrobium orchids are normally grown under iron frame shade net houses which are quite vulnerable to cold injury during extreme winter period and heavy rain during monsoon period. Further, the existing structures are very costly which is not affordable by small and marginal farmers of Assam. Keeping in view the current study was aimed to evaluate a suitable low cost protected structure for commercial cultivation of Dendrobium cv. Sonia under Assam condition.&nbsp; 
 
Methods: An experiment was conducted in the Horticulture Experimental Farm, Assam Agricultural University, Jorhat, during 2018-2019 which was laid out in factorial completely randomized design with 10 treatment combinations replicated five times. The first factors comprised 5 numbers of low cost protected structures viz., G1, G2, G3, G4 and G5. The second factors comprised T1-1 tier and T2-2 tiers. 
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Result: The results revealed that among the protected structures, healthy growth and better quality flowers were obtained under G1 (Bamboo frame structure covered with fixed 200 micron UV film with top ventilated and 50% agro shade net as ceiling) protected structure followed by G4. Between the tiers, T2 was found to be superior in respect of the growth characters as well as most of the flower characters. So, this treatment combination is merits consideration for commercial growers of Assam to bring about timely and quality flower production of Dendrobium cv. Sonia.</div>

Evaluation of Low Cost Protected Structure for Commercial Cultivation of Dendrobium Cv. Sonia under Assam Condition

Experiment was carried out to standardize media mixture for hardening of in vitro plantlets of Dendrobium hybrid Sonia-17 during the year 2013-2014. The results revealed that three pieces coconut husk tied with the ex-agar plantlets and planted in portray containing cocopeat significantly enhanced the formation of new leaves/plantlet (5.3), number of roots/plantlets (7.5), length of the root (2.5cm) and percentage of survival (96.67%) of the plantlets.

Efficient Surface Sterilant for Establishment of Dendrobium in vitro Culture

Evaluation of Low Cost Protected Structure for Commercial Cultivation of Dendrobium Cv. Sonia under Assam Condition

Standardization of media mixture for hardening of in vitro plantlets of Dendrobium cv. Sonia-17