Somatic Embryogenesis and Plant Regeneration in Horticultural Crops

Globalization of agriculture leads to competitiveness in the production of food crops, especially in horticulture. The rate of multiplication of desirable plants by traditional breeding methods is slow and nature-dependent. Horticultural crops such as fruits and plantation crops are perennial and natural and must pass across prolonged juvenile phases for seed production. Somatic embryogenesis (SE) is one of the powerful biotechnology tools by which a somatic or vegetative plant cell is transformed into an embryo for commercial propagation. Somatic embryogenesis can help in the rapid and mass multiplication of newly released and improved varieties. Obtaining true-to-type plants in cross-pollinated plants is difficult because of their heterozygous nature. The mass multiplication of true-to-type plants with desired traits in in vitro conditions within a short period is possible by this method. It is a complex process and is controlled by several types of external and internal triggers. Plant regeneration through somatic embryogenesis offer merits over organogenesis in exploiting the feasibility of single-cell origin and accomplishing spontaneous production of embryos on large scale. Synthetic seeds produced through the process of somatic embryogenesis can be availed for direct field planting, and the plants have less bearing time compared with plants produced by conventional breeding methods. The bipolar nature of embryos produced by somatic embryogenesis permits the development of plantlets without the need for the separate root development stage unlike organogenesis in the in vitro method of propagation. In this chapter, the latest advances in somatic embryogenesis of major and commercially important crops are described.