Somatic embryogenesis in Arachis hypogaea: revisited

Abstract

Direct somatic embryogenesis is an efficient method of plant regeneration, allowing rapid multiplication of plants in a short period. Six experiments were conducted to study the influence of auxin level on somatic embryogenesis and to optimise the concentration of auxins. Immature embryo axis was the ideal explant and 20–40 mg L–1 of 2,4-dichlorophenoxyacetic acid was the best concentration range for obtaining the maximum number of free somatic embryos. Significant differences were observed between the genotypes for induction and the number of somatic embryos per explant. The cv. Girnar 1 produced the maximum number of somatic embryos per explant, the number of secondary somatic embryos ranging from 1.5 to 9.4. The overall germination of somatic embryos was 42.8%, and 65% of the plantlets transferred to the field survived. The development of somatic embryos was from the apical region of the embryo axes without undergoing dedifferentiation. The initial cell divided to form a tier of four cells and subsequent anticlinal and periclinal division resulted in the development of globular somatic embryos with small suspensors, followed by heart-shaped, torpedo-shaped and ‘cotyledonary’ stages.

Factors promoting efficient in vitro regeneration from de-embryonated cotyledon explants of Arachis hypogaea L.

“…However, crop improvement through genetic engineering, requires the availability of efficient regeneration systems. Extensive research in recent years has led to the development of protocols for in vitro regeneration of peanut through organogenesis (Cheng et al 1992;Chengalrayan et al 1995;Kanyand et al 1997;Akasaka et al 2000;Sharma and Anjaiah 2000) and embryogenesis (Sellars et al 1990;Ozias-Akins et al 1992;Baker and Wetzstein 1998;Little et al 2000;Radhakrishnan et al 2001) from various explants. However, most of the reports show low regeneration efficiency and time consuming development of the regenerants.…”

Factors affecting somatic embryogenesis and transformation in modern plant breeding

“…For example, out of the five cultivars of Hybrid Tea roses (Rosa hybrida L) investigated, somatic embryogenesis could only be induced in two (Kim et al, 2003). A similar phenomenon has been observed in red clover (McLean and Nowak, 1998), peanut (Arachis hypogea) (Radhakrishnan et al, 2001) and Chinese cotton (Zhang et al, 2001). The presence of varying levels of endogenous phytohormones, particularly cytokinins, in different genotypes might influence their response to somatic embryogenesis.…”

“…Variations in in vitro response have been known to occur due to a number of different factors, such as basal medium (Zegzouti et al, 2001), explant source (Sharma and Rajam, 1995;Haliloglu, 2002) and genotype (Radhakrishnan et al, 2001;Kim et al, 2003).…”

Hemoglobin Promotes Somatic Embryogenesis in Peanut Cultures

“…Such embryos can be exploited directly for the mass propagation of plants or, following further multiplication often under bioreactor conditions, via ''artificial seed'' technology. Protocols have been reported for plant regeneration in peanut through somatic embryogenesis using immature zygotic embryos, seedling cotyledons, hypocotyls and epicotyls, or leaflets (Little et al, 2000;Radhakrishnan et al, 2001), as sources of explants.…”