In vitro somatic embryogenesis and plant regeneration of cassava

Abstract

An efficient and reproducible plant regeneration system, initiated in somatic tissues, has been devised for cassava (Manihot esculenta Crantz). Somatic embryogenesis has been induced from shoot tips and immature leaves of in vitro shoot cultures of 15 cassava genotypes. Somatic embryos developed directly on the explants when cultured on a medium containing 4-16 mg/l 2,4-D. Differences were observed with respect to the embryogenic capacity of the explants of different varieties. Secondary embryogenesis has been induced by subculture on solid or liquid induction medium. Long term cultures were established and maintained for up to 18 months by repeated subculture of the proliferating somatic embryos. Plantlets developed from primary and secondary embryos in the presence of 0.1 mg/l BAP, 1mg/l GA3, and 0.01 mg/l 2,4-D. Regenerated plants were transferred to the field, and were grown to maturity.

Effect of medium composition and explant size on embryogenic calli formation of cassava (Manihot esculenta Crantz) local genotypes

“…Joseph et al (2004) juga menggunakan kalus embriogenik sebagai bahan penelitian induksi mutasi pada ubi kayu melalui iradiasi sinar-γ. Eksplan yang berasal dari jaringan somatik seperti daun pucuk juga dapat digunakan untuk inisiasi sistem regenerasi tanaman yang efisien, oleh karena itu Szabados et al (1987) menggunakan tunas pucuk dan daun muda ubi kayu yang berasal dari kultur in vitro sebagai eksplan. Dilaporkan oleh Joseph et al (2000) bahwa kalus embriogenik juga telah berhasil diinduksi dari daun pucuk muda kerabat ubi kayu penghasil getah yaitu Manihot glaziovii Muell.…”

“…Persentase kalus embriogenik tertinggi (100%) ditunjukkan oleh genotip Iding yang berasal dari ukuran eksplan 3-5 cm yang diinkubasi pada media GD, sedangkan terendah (33%) ditunjukkan oleh genotip Timtim 29 yang berasal dari ukuran eksplan lebih dari 5 mm yang diinkubasi pada media yang sama (Gambar 1B). Szabados et al (1987) menyatakan bahwa setiap varietas ubi kayu mempunyai kemampuan yang berbeda dalam menghasilkan kalus embriogenik. Respon tanaman untuk menghasilkan tunas baru (multiplikasi tunas) atau kalus embriogenik bervariasi bergantung kepada banyak faktor antara lain bagian tanaman yang digunakan, umur fisiologis bagian tersebut atau umur pohon induk, jenis tanaman dan prosedur perbanyakan termasuk jenis zat pengatur tumbuh yang ditambahkan pada media (Sudarmonowati et al, 2002).…”

Cassava Biotechnology

“…cotyledons or embryonic axes from zygotic embryos (Stamp andHenshaw, 1982, Konan el al., 1994a,b), immature leaf lobes (Stamp and Henshaw, 1987a;Szabados et al, 1987;Mathews et al, 1993;Raemakers, 1993;Raemakers et al, 1993a;Li et al, 1995Li et al, , 1996Li et al, , 1998, meristems and shoot tips (Szabadosetal., 1987;Narayanaswamietal.., 1995;Puonti-Kaerlaset al, 1997a), and immature inflorescences (Mukherjee, 1995; Puonti-Kaerlas and Woodward unpublished data) on auxin-containing media. Picloram at 1-12 mgll, dicamba at 1-66 mgl I and 2,4-D at 1-16 mg/l have been used to induce primary somatic embryogenesis, the efficacy of the different growth regulators depending on the explant and the cultivar used (Ng, 1992;Mroginsky and Scocchi, 1993;Sudarmonowati and Henshaw~1993;Taylor et al.…”

“…A new method including a culture step on hormone-free medium containing 0.5% activated charcoal followed by desiccation before transfer to hormone-free medium allowed up to 83% plant regeneration from genninating embryos with normal root development (Matthews et al, 1993). Likewise, additional GA J was shown to be beneficial for the further development of shoots from somatic embryos (Matsumoto et al, 1991;Szabados et al, 1987).…”

Induction of cassava somatic embryogenesis in liquid medium associated to floating membrane rafts

“…Based on this system, the production of the first transgenic cassava plant by particle bombardment was reported (Schöpke et al, 1996). Although Szabados et al (1987) and Stamp and Henshaw (1987) suggested the possibility of somatic embryogenesis induction on liquid medium, conclusive data on this subject were not reported.…”