Chapter 11 - Embryo rescue: A potential tool for improvement of economically important crops

Abstract

Crop improvement has always been a major concern to feed the continuously increasing human population. Since they trigger genetic rearrangement, the flowering traits in plants are the foundation of all breeding approaches. Flowers can set seeds after natural or artificial pollination, which means they can be improved genetically using conventional breeding methods. Unfortunately, any crop reaches the point where its genetic pool is exhausted and can no longer be improved. The breeders are looking for crop wild relatives to identify candidate genes with desirable traits. In general, cross-pollination between cultivated and wild relatives produces unusual barriers. However, in terms of incompatibility, congruity and incongruity lead to unsynchronized floral organ production and disturbances in postfertilization seed setting. However, the embryo can abort even after successful fertilization due to genetic incompatibility and environmental factors. Postfertilization transcription factors suppress embryo growth and prevent viable seed production at the molecular level. To prevent interspecific hybridized embryos from abortion, they are technically excised in vitro and cultured on media, referred to as “embryo rescue” (ER). ER is one of the oldest in vitro plant breeding strategies. Many factors influence the effectiveness of the ER technique, including crop genotype, culture media, plant growth regulators, the age of the fruit, and the more significant stages of the rescued embryos. When compared to other embryo stages, the torpedo stage embryo has the highest success rate. For field and horticultural crops, the ER technique was a boon for interspecific and intergeneric hybrids. Precocious germination, malnutrition, cytological changes during embryogenesis, endosperm balance number, and polar nuclei activation are several triggers of interspecific hybridization failure that can be resolved using this technique. Seed physiology, viability, and dormancy, as well as ploidy and various chromosome elimination research, all benefit from ER. As a result, this method has been very effective for the interspecific hybrid development in a various vegetable, fruits, and ornamental and field crops. The ER technique’s facilitates growers, plant breeders, and the seed industry for global food and nutrition security. This chapter provides updated and detailed information about ER techniques, influences, and applications in commercial crops.