Rice

Chemistry and Technology

Jinsong Bao

• Publisher: Woodhead Publishing and AACC International Press
• Year: 2018
• Print ISBN: 9780128115084
• eBook ISBN: 9780128115091
• Edition: 4
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Rice Chemistry and Technology, Fourth Edition, is a new, fully revised update on the very popular previous edition published by the AACC International Press. The book covers rice growth, development, breeding, grain structure, phylogenetics, rice starch, proteins and lipids. Additional sections cover rice as a food product, health aspects, and quality analysis from a cooking and sensory science perspective. Final chapters discuss advances in the technology of rice, with extensive coverage of post-harvest technology, biotechnology and genomic research for rice grain quality.With a new, internationally recognized editor, this new edition will be of interest to academics researching all aspects of rice, from breeding, to usage. The book is essential reading for those tasked with the development of new products.- Identifies the nutrition and health benefits of rice- Covers the growing and harvesting of rice crops- Includes the use of rice and byproducts beyond food staple- Explains rice chemistries, including sections on starch, protein and lipids- Contains contributions from a world leading editorial team who bring together experts from across the field- Contains six new chapters focusing on rice quality

1

Origin, taxonomy, and phylogenetics of rice

Xin Wei, and Xuehui Huang College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China

Abstract

Rice (Oryza sativa L.) is one of the most important staple crops, feeding almost half of the world population. It is cultivated worldwide with a concentration in Asia. Rice domestication has greatly influenced the history and civilization of humans. Despite the primacy of rice, when, where, and how rice was domesticated was debated for decades. With much effort and the development of genomics, a comprehensive domestication map of rice subspecies was built recently. In this chapter, we discuss recent genetic work that is related to the origin, taxonomy, and phylogenetics of rice, and we describe the genomic research into the domestication of indica and japonica. Characterization of domesticated rice genes will lay a solid foundation for molecular breeding in the future.

Keywords

Domestication; Genomics; Geographic origin; Oryza rufipogon; Phylogenetics; Rice; Taxonomy

Rice, generally referred to as Asian cultivated rice (Oryza sativa L.), is one of the most important staple crops, feeding almost half of the world population. It is widely cultivated around the world and mainly in Asia. Domesticated rice has played a central role in human nutrition and culture during the past 10,000 years. The domestication of rice is one of the most important technological innovations in Asian history, significantly supporting the formation of two of the four ancient civilizations. There is no doubt that rice is one of the most important influential crops in Asia. However, the origin and the domestication processes of cultivated rice have been debated for decades, which is inconsistent with the important position of rice. In this chapter, we discuss recent genetic and archaeological work that reveals the origin, taxonomy, and phylogenetics of rice, and we describe the genomic research into the domestication of subspecies of rice. The development of genomic methods provides a clear picture of the domestication of rice and will certainly benefit the rice functional genomics studies and molecular breeding in the future.

1. Natural genetic variation in rice

1.1. Geographic distribution of rice and its phenotypic diversity

Nowadays rice is widely planted in more than 120 countries across the world, from 35°S to 53°N, with a concentration in tropical and subtropical areas of Asia. From 2010 to 2014, the world harvest area of rice was 163 million hectares per year, led by India, China, Indonesia, Bangladesh, and Thailand with a combined 67% of total (FAO, 2014). The planting area of rice increased approximately 42% in the last 50 years and is still increasing gradually. The increased planting area was mainly in Southeast and South Asia (about 75%), led by India, Indonesia, Thailand, China, and Vietnam. China and India are the biggest rice production countries, which produced approximately 50% of the world's rice. Rice is mainly grown in the Yangtze River basin, southeast coastal area, and northeast area of China. The planting region of rice in northeast area increased quickly in the last decades. The Gangetic Plain and coastal areas are the major rice production areas in India.

More than 400,000 rice accessions have been collected in the public germplasm repositories. The large germplasm resources conservation center of rice includes the International Rice Research Institute (>100,000 rice accessions), National Crop Genebank of China (>80,000), National Plant Germplasm System of United States Department of Agriculture (USDA, >18,000), and National Bureau on Plant Genetic Resources of India (>60,000). These accessions show various phenotypes and many agronomic traits, such as heading date, plant height, seed shape, pericarp color, and grain weight. Take the seed color for example, it could be white, red, black, brown, purple, or green. Rice is classified into two subspecies by their grain shapes and texture: indica and japonica. Generally, indica is long grain, relatively less sticky, with less amylopectin, while japonica is short grain and more sticky. Besides seed shape and texture, indica and japonica show significant differences in plant height, leaf shape, leaf color, plant type, awn length, density of glume pubescence, germinating rate, cold tolerance, lodging resistance, disease resistance, seed shattering, tiller number, and many other agronomic traits. Compared to indica, the japonica varieties have shorter plant height, shaper leaf shape, light leaf color, strong cold tolerance, strong lodging resistance, are nonshattering, but have lower tiller number, slower germinating rate, are sensitive to rice blast, have long and dense glume pubescence and long awn in some varieties. Differences between nonsticky (indica) and sticky (japonica) rice are even documented in Chinese literature as early as AD 100 (Matsuo et al., 1997).

Indica varieties are concentrated in the mostly submerged region in South Asia and Southeast Asia, while japonica varieties are mainly grown in the fields with less water, such as northern latitudes of East Asia, upland areas of Southeast Asia, and high elevations in South Asia. The planting area of japonica is about 13 million hectares, less than 10% of the total. Most japonica is grown in China (about 60%), and over 80% of it is in Northeast China, East China, and Yunnan-Guizhou Plateau.

1.2. IRGSP and OMAP

To meet the projected food demands of growing populations, the world rice production must increase by 30% over the next 20 years. The utilization of biotechnology and molecular breeding to increase the rice yield potential and yield stability is particularly important, in which a high quality reference rice genome sequence is much required. The International Rice Genome Sequencing Project (IRGSP), established in 1998, set the power of sequencing groups from 10 nations to draw a complete precise map of the rice genome (Nipponbare, a japonica cultivar). The IRGSP released a high-quality finished genome sequence of japonica rice in 2005. The rice genome is the first completely sequenced monocot plant genome and the second plant genome after Arabidopsis (a dicot). The highly accurate and public IRGSP sequence opened the door for functional characterization of the rice genome and permitted rice geneticists to identify the genes underlying complex agronomic traits. Based on the rice genome, understanding of the biological function of rice genes and the genetic improvement of rice production and quality has been greatly facilitated. Through comparative analyses, the domestication and evolution research of rice and other cereal crops was also largely promoted (Paterson et al., 2004; Salse et al., 2008; Wang et al., 2005; Yu et al., 2005). Benefiting from the high quality genome and other research for rice, such as the smallest genome of the major cereals, dense genetic maps and relative ease of genetic transformation, rice has been developed to be one of the model species for molecular and genetic research in pla...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Preface to the fourth edition
• Preface to the third edition
• Preface to the second edition
• Preface to the first edition
• 1. Origin, taxonomy, and phylogenetics of rice
• 2. Gross structure and composition of the rice grain
• 3. Rice starch
• 4. Rice proteins and essential amino acids
• 5. Rice lipids and rice bran oil
• 6. Rice minerals and heavy metal(oid)s
• 7. Rice vitamins
• 8. Rice phenolics and other natural products
• 9. Rice end-use quality analysis
• 10. Rice milling quality
• 11. Rice appearance quality
• 12. Rice cooking and sensory quality
• 13. Impact of climate change on rice grain quality
• 14. Biotechnology for rice grain quality improvement
• 15. Postharvest technology: Rice drying
• 16. Postharvest technology: Rice storage and cooling conservation
• 17. Rice noodles
• 18. Rice in brewing
• 19. Utilization of rice hull and straw
• Index