Section 1 Biotechnology

**3**

**Chapter 1**

**Abstract**

Observations on Somatic

*Julieta Andrea Silva de Almeida*

as factors that may affect its control.

somatic embryos

**1. Introduction**

industry.

Embryogenesis in *Coffea arabica* L.

Somatic embryogenesis contributes to coffee breeding programs. This is a process of asexual reproduction which is based on the concept of cellular totipotency. Each haploid or somatic cell of the plant tissue has the genetic information necessary to generate a complete and functional plant. The somatic embryogenesis can occur either indirectly or directly. *Coffea arabica* genotypes may respond to direct, indirect, or both. In this species, the indirect somatic embryogenesis is composed of two phases, the callogenesis and the embryogenesis, while the direct pathway occurs in a single phase, without the callogenesis. In *Coffea*, in general, the indirect pathway is induced by the auxin and cytokinin, and the direct pathway with cytokinin only. *C. arabica* genotypes usually respond easily to the indirect route with high production of somatic embryos. But these are inefficient by the direct route because they present low production of embryos and the process occurs for a long time. In this review, emphasis will be given to different events that are part of the somatic embryogenesis of *C. arabica* occurring indirectly and in the direct pathway as well

**Keywords:** Callus, leaf explant, plant hormone, embryogenic structures,

The genus *Coffea* belongs to the Rubiaceae family and has over 100 species [1]. However, only *Coffea arabica* and *Coffea canephora* species are commercial, the former accounting for almost 75% of world coffee production and the latter for the remaining 25%. Brazil is the world's largest producer and exporter of coffee accounting for about 70% of world exports [2]. *C. arabica* has this hegemony for producing pleasant and stimulating drink that is consumed worldwide while *C. canephora* coffee is less palatable and is intended primarily for the instant coffee

*Coffea* breeding aims to combine genotypes of *C. arabica* and *C. canephora* spe-

[3, 4]. In conventional *Coffea* breeding it takes six to eight selection cycles to generate a new cultivar, which is about 40 years. Each cycle corresponds to five years. But it takes four to five harvests to consistently evaluate a generation [5]. In addition, it is important that evaluations are performed on plants over five years of age to obtain reliable yield data [6]. In the breeding program, during the selection phase intermediate populations of progenies are generated and each one of them has dif-

cies to release genetically stable varieties with strong traits of both species

ferent genetic pattern. Thus each progeny corresponds to a single plant.
