Advances in Rice Science

Botany, Production, and Crop Improvement

Ratikanta Maiti, PhD, Humberto González Rodríguez, PhD, Ch. Aruna Kumari, PhD, Narayan Chandra Sarkar, PhD, Sameena Begum, Dasari Rajkumar

• Publisher: Apple Academic Press
• Year: 2020
• ISBN:
  9781000517569
• Edition: 1
• Topic: Art
• Subtopic: Culinary Arts

During recent decades, tremendous progress and innovations have been made in rice science with the goal of increasing production to meet the world's growing demands. This new volume provides a concise overview of rice, covering the background and importance of rice; origin, evolution, and domestication of rice; and the world rice production. It goes on to provide new and important recent research advances on many different aspects of rice science and production. The authors look at advances in rice ideotypes, abiotic stress management techniques, biotic stress affecting crop productivity, new methods and technology for cultivation, and new methods and techniques in rice grain quality analysis and processing. It also describes new rice varieties, new hybrid rice technology, and new breeding methods for rice.

CHAPTER 1

Background and Importance of Rice

ABSTRACT

This chapter presents the background and importance of rice (including its various industrial products) at the global level and discusses rice-growing environments together with the prospects of rice production. Rice is a staple food and has high demand across the World. Additionally, rice is also a vital source for the supply of essential elements.

1.1 BACKGROUND AND IMPORTANCE OF RICE

Rice is a very important cereal crop. It is under cultivation for more than 7,000 years. At present, it sustains the food necessities of more than half of the World population. Significant research advances have been attained. This involves efficient transformations, development of saturated molecular maps and massive analysis of expressed sequence tags. In this respect, we analyzed the number of complementary DNAs of rice and that of Arabidopsis are near equal numbers. Therefore, it is being considered as a model plant of the monocotyledonous group (Takeshi and Shimamoto, 1996).

Besides, its food value for millions of population, various rice products viz. rice brans, husks, etc., are utilized for various purposes.

1.1.1 ORIGIN AND DISPERSAL OF RICE

Khush (1997) discussed the origin, dispersal, cultivation, and variations of rice. He mentioned that the genus of rice Oryza contains both two cultivated and 21 wild species. The O. sativa, usually referred to as the Asian cultivated rice, all across the global regions is grown in many areas. The African cultivated rice, O. glaberrima, when compared to the Asian cultivated rice its cultivation is confined to small regions of West Africa. This genus Oryza was assumed to be originated 130 million years in the past in Gondwanaland. Further, with the shuffling up of Gondwanaland region, different species might have been dispersed into different continents. Most of these cultivated species of rice were opined to have their origin from a common ancestor that had AA genome. The perennial and annual ancestors of O. sativa are O. rufipogon and O. nivara. Likewise, O. longistaminata and O. breviligulata were the perennial and annual family relatives (ancestors) of O. glaberrima. O. glaberrima might have been domesticated probably in Niger River delta. On the basis of genetic affinity backgrounds, the varieties of O. sativa are generally categorized into six groups. Among this widely known rice is that of the indicas and this matchup to group (I) and japonicas to group (VI). The javanica rice does also belong to group (VI). These are nominated as tropical japonicas, in disparity to temperate japonicas, grown largely in temperate climates. The indica and japonica rice had a polyphyletic derivation (origin). The indicas were perhaps mostly cultivated (domesticated) in the Himalayan foothills of Eastern India while the japonicas were evidenced to be domesticated in South China. The indica rice from India was dispersed all over the regions of tropics and of subtropics; while the japonica rice had a move northward from South China. They turned out as temperate ecotypes. The japonica rice, moved southward to Southeast Asia and later from there to West Africa and Brazil and became the tropical ecotype. Rice is now grown between 55°N and 36°S latitudes, under dissimilar growing environments such as irrigated, rainfed lowland, rainfed upland, and flood-prone ecosystems. Numerous cultivars have resulted because of their adaptations to varied environments and human selections. Estimations revealed that there are about ~120,000 varieties of rice existing within the World. With the founding of the International Rice Research Institute (IRRI) in 1960, intensification of rice, varietal improvement programs have occurred; several high yielding varieties that were developed were released. Most of these rice varieties are planted across 70% of rice lands in the World. With the extensive taking up of cultivation of these improved varieties of rice, rice production was doubled between 1966 and 1990. In spite of the presence of doubled production for feeding the surplus rice consumers and increased populations, presently; there is a requisite for an increase in rice production by 2025 to an extent of 60%. The novel paraphernalia of molecular and cellular biology viz., anther culture, molecular markers which have aided in the selection and genetic engineering will have additional mounting roles to bring about rice improvement.

Chang (1984) reported about the ethnobotany of rice in Island Southeast Asia with reference to the perspectives of Asia. He mentioned that this genus Oryza, containing the rich cultigens O. sativa L. and O. glaberrima has long antiquity. These had their origin to Gondwanaland and have undergone interspecific differentiation, before the supercontinent were fragmented and drifted apart. This was indicated by the pantropical distribution of the wild species of the genus in a nondisjunct manner across Africa, Oceania, and Latin America. The geographic distribution of the wild species with known genomes (chromosomal complements) reflects a charming picture of a widely dispersion of semiaquatic grass, rice.

The process of near beginning rice cultivation, followed two pathways for its domestication within India and China. Selection of domestication traits found in the near beginning in Yangtze japonica and a non-domestication feedback system inferred for ‘proto-indica.’ This domestication process was completed approximately 6,000–6,500 years ago in China and about two millennia, later in India. By this time, there was hybridization in Chinese rice. Later, farming populations increased and then stretched over by migration and introgression of pre-existing populations. These spreading outs can be connected to hypothetical language family dispersal models, which include scattering from China southwards by the Sino-Tibetan and Austronesian groups. In South Asia, much diffusion of rice occurred after Indo-Aryan and Dravidian speakers have taken over rice from the speakers of lost languages of parts of northern India (Fuller, 2011). In this process, the combined efforts of information of modern genetics, ecology, and archaeology have helped in unveiling the process of rice domestication and diversification.

Archeological excavations and environmental archeological investigations conducted for several years in the Shanghai Area have offered immense, valuable, and excellent information for Holocene environmental changes, growth which led to subsequent turndown of human settlements and man-land interactions. Wu et al. (2014) discussed Holocene environmental change and its influences on human settlement in the Shanghai area, East China. Division and circulation of archeological sites between 7,000 and 3,000 cal. yr BP demonstrated a regression process. It advanced southward of the coastline. Temporal and spatial analyses of ¹⁴C dates for archeological sites, shell ridges, buried trees, and peat suggested that Holocene environmental changes might have been a major cause of the rise and fall of human settlements and their civilization. A virtual sea-level curve of the Shanghai area which was obtained from dated shell ridges and peat correlated well with the reconstructed sea-level curves of the Yangtze Delta and East China. As this process was going on, the development of human settlements was broken up at least four times in the Shanghai Area, coinciding with four periods of high sea-level, peat accumulation, and amplified in shell ridges. They stated that after this, Neolithic communities migrated to the plain and occupied their lowlands for rice cultivation. In this aspect, the Chenier Ridges played a vital part in giving shelters to the settlers of the Neolithic period. The crumple of Liangzhu Culture about 4,000 cal. yr BP was followed by a lesser amount of developed Maqiao Culture. These studies suggested that the prevalent extreme environmental and hydrological conditions such as terrestrial inundation resulted due to sea-level rise and heavy precipitation led to the end of paddy exploitation and to the social stress that bring about the Liangzhu Culture demise.

Zhu et al. (2012) discussed sequence polymorphisms in wild, weedy, and cultivated rice. The results suggested that seed shattering locus sh4 had a very negligible function in domestication of Asian rice. The major view on domestication of Asian rice was that the preliminary origin of non-shattering is associated with a single gene of large effect, particularly, the sh4 locus through the evolutionary substitution of a dominant allele for shattering with a recessive allele for reduced shattering. Sufficient data have been collected to challenge this assumption. In this respect specifically, a few reports have mentioned about the occurrence of occasional seed shattering plants from populations of the untamed progenitor of cultivated rice (Oryza rufipogon complex). These plants were homozygous for the putative “nonshattering” sh4 alleles. The authors tested the sh4 hypothesis for the domestication of cultivated rice by collecting genotypes and phenotypes from a diverse set of samples of wild, weedy, and cultivated rice accessions. The cultivars were fixed for the putative “nonshattering” allele and nonshattering phenotype, but wild rice accessions were highly polymorphic for the putative “nonshattering” allele (frequency ~26%) having shattering phenotype. All weedy rice accessions are the “nonshattering” genotype at the sh4 locus but with shattering phenotype. These statistics challenge the widely accepted hypothesis that a single nucleotide mutation (“G”/“T”) of the sh4 locus is the major driving force for rice domestication. Instead, the authors hypothesized that anonymous shattering loci are liable for the early domestication of cultivated rice through abridged seed shattering.

1.2 ROLE OF RICE IN HUMAN CIVILIZATION

Rice plays a key part in human civilization and occupies the space of a vital component of human society. It boosted human civilization, increased the human population and the national economy. There are several evidences that rice is closely associated with human culture and their civilization, and an increase in population.

Rice was basically a tropical semiaquatic swamp grass, before the dawn of agriculture. With the commencement of agriculture, it became a supplementary food to those people, who were much dependent on hunting, fishing, and gathering of other food plants for their subsistence living. Its farming serves to be a subsistence level of livelihood, in several regions of humid tropics where many harsh environments prevail. In areas of proper management practices adopted in the conservation of water, nutrients, or with well soil fertilization, tillage, and weeding practices along with good plant selection are practiced, its yields quite astonishingly increased at a faster pace. The surplus food production that was attained with the adoption of the good management practices helped in meeting the food requirements of the increased population. Henceforth, there was an expansion in rice acreage, an increase in rice yield, and multiple cropping systems. These, in turn, boosted the civilizations flourishing in several countries of Asia. Thereby, this lowly swamp plant during the past two millennia in many Asian countries has provided the impetus for accelerated progress in their national economies and the cultural improvements, even though there were increases in the populations (Chang, 1987).

1.3 RICE PRODUCTS

1.3.1 ENRICHMENT OF SELENIUM CONCENTRATION IN RICE PRODUCTS

In Southern China, Qiuhui et al. (2002) analyzed 30 rice products for sel...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• About the Authors
• Contents
• Abbreviations
• Acknowledgment
• Preface
• 1 Background and Importance of Rice Background and Importance of Rice
• 2 World Rice Production
• 3 Origin, Evolution, and Domestication of Rice
• 4 Rice Ideotype
• 5 Rice Botany
• 6 Physiological Basis of Rice Growth and Productivity
• 7 Research Advances in Abiotic Stress Management
• 8 Biotic Stress Affecting Crop Productivity
• 9 Methods of Cultivation
• 10 Rice Grain Quality Analysis, Food Quality, Chemistry, and Food Processing
• 11 Improvement of Rice: Rice Varieties and Hybrid Rice Technology
• 12 Research Advances in Breeding and Biotechnology of Rice
• Index