Protocol for the Micropropagation of Coconut from Plumule Explants

Abstract

Coconut is a crop that is economically important in several countries throughout the world. Unfortunately, production is decreasing because palms are affected by very serious phytoplasma diseases, such as lethal yellowing, and also most of coconuts are already very old. On the other hand, markets for coconut products have been rapidly growing in recent years. Hence, replanting of most cultivation surface worldwide, as well as establishing new surface, is urgently needed. This is an immense task, requiring at least a billion coconut palms that cannot be accomplished by traditional propagation through seed. Therefore the biotechnological alternative of micropropagation by somatic embryogenesis is needed. Research has been carried out on this subject in laboratories in several countries studying different approaches, testing different types of explants. The most responsive tissue has been plumule from zygotic embryos. A protocol for micropropagation of coconut based on plumule explants is described here. It involves the use of different media that are based on Y3 medium complemented with activated charcoal, gelling agent, sucrose, and growth regulators. These media allow the formation of embryogenic callus and somatic embryos, growth of shoots, and development of plantlets.

Effects of Surface Sterilization Protocol and Haustorium Removal on Germination and Growth of Hybrid PB121 Coconut Palm (Cocos nucifera L.) Zygotic Embryos Cultured in vitro

“…The basic medium Y3 modified by Weerakoon et al [17] and Sáenz et al [18] was used as germination medium for zygotic embryos. The sprout formation medium was prepared using the Y3 medium formulation, with the addition of 7 g/L agar, 2.5 g/L activated charcoal, 5% sucrose, 6.10-3 mM 2,4-D and 0.3 mM BAP and a volume of 25 ml was dispensed into each of the 150 ml jars for tissue culture.…”

In vitro transmission of 16SrIV phytoplasmas to coconut plants by Haplaxius crudus in Yucatan, Mexico

“…In Mexico 16SrIV phytoplasmas of different ribosomal subgroups have been detected in coconut and other palm species (-A, -B and -D) (Harrison et al 2002;Narvaez et al 2018;Vázquez-Euán et al 2011;Córdova Lara et al 2017) and in H. crudus (-A, -D and -E) (Narvaez et al 2018). Transmission studies showed that H. crudus could transmit phytoplasmas of subgroups -A and -D to P. pacifica (Dzido et al 2020).…”

“…Coconut plants were produced by micropropagation through somatic embryogenesis as described in Saenz et al (2018). They were about 20 cm long and had at least three main roots and three developed leaves, as shown in Fig.…”

Cloning Coconut via Somatic Embryogenesis: A Review of the Current Status and Future Prospects

“…More recently, plumular tissues from germinating zygotic embryos [11,[36][37][38] and rachilla sections from immature inflorescences [39,40] have been successfully used for coconut SE. Of these, the plumular tissue was found to be the most suitable for SE [30,[41][42][43].…”

“…According to Montero-Córtes et al, 2010 [74], GA 3 (0.5 µM) improved the formation and germination of coconut somatic embryos, with the maturation rate increasing 1.5-fold, and the number of somatic embryos formed per callus clump increasing 2.0-fold. Gibberellic acid has also been included in a recent protocol developed for the germination of coconut somatic embryos derived from plumular [38] and inflorescence tissues [39] at concentrations of 2.8 and 4.6 µM, respectively.…”