**Abstract**

Cereals are a rich source of vitamins, minerals, carbohydrates, fats, oils and protein, making them the world's most important source of nutrition. The influence of rising global population, as well as the emergence and spread of disease, has the major impact on cereal production. To meet the demand, there is a pressing need to increase cereal production. Optimal seed development is a key agronomical trait that contributes to crop yield. The seed development and maturation is a complex process that includes not only embryo and endosperm development, but also accompanied by huge physiological, biochemical, metabolic, molecular and transcriptional changes. This chapter discusses the growth of cereal seed and highlights the novel biological insights, with a focus on transgenic and new molecular breeding, as well as biotechnological intervention strategies that have improved crop yield in two major cereal crops, primarily wheat and rice, over the last 21 years (2000–2021).

**Keywords:** Seed development, yield related agronomic trait, genetic, molecular and transcriptome studies

#### **1. Introduction**

Cereal seeds are the major source of starch and proteins in staple foods, animal feed, and raw materials for food and fiber-based industries all over the world [1]. Considerable efforts have been made to elucidate the molecular mechanism regulating important agronomic traits in order to improve the cereal seed production. Several agronomic traits, including grain number per spike, spike length, thousand seed weight, seed size and many others, have contributed to grain yield improvement in many cereals plants, with the development of embryo, endosperm and integuments being the most important [2]. As a result, better understanding of the genetic and molecular processes governing seed development is crucial. Here in this book chapter, we provide a comprehensive review on the ontogeny of seed development, followed by genetics, molecular and transcriptional regulation of seed development for improved crop yield.
