Amaranthus: A Promising Crop of Future

Description

This book serves the larger community of plant researchers working on the taxonomy, species delimitation, phylogeny, and biogeography of pseudo-cereals, with a special emphasis on amaranths. It also provides extensive information on the nutritive value of underutilized pseudo-cereals, the goal being to broaden the vegetable list. Amaranthus is a cosmopolitan genus of annual or short-lived perennial plants. Most of the species are summer annual weeds and are commonly referred to as pigweed. Only a few are cultivated as vitamin-rich vegetables and ornamentals. The protein-rich seeds of a handful of species, known as grain amaranths, are consumed as pseudo-cereals. Amaranthusmanifests considerable morphological diversity among and even within certain species, and there is no general agreement on the taxonomy  or number of species. Currently the genus Amaranthus is believed to include three recognized subgenera and 70 species. Amatanthus is considered to potentially offer an alternative crop in temperate and tropical climate. The classification of amaranths is ambiguous due to the lack of discrete and quantitative species-defining characteristics and the wide range of phenotypic plasticity, as well as introgression and hybridization involving weedy and crop species. It is a known fact that both vegetable and grain amaranths have evolved from their respective weed progenitors. There are more than 180 different weed species that are herbicide-resistant, and amaranths are considered to be leading members of the resistant biotypes. Amaranth species provide ample scope for investigating herbicide resistance mechanisms. Amaranths also show variability in terms of their mating behavior and germplasm, adaptability to different growing conditions, and wide range of variability in sexual systems, from monoecy to dioecy. A solid grasp of these parameters is essential to the future utilization of amaranths as super crops. There are quite a few amaranth research center and germplasm collections all over the world that maintain and evaluate working germplasms. To date, the genetic improvement of amaranths has primarily involved the application of conventional selection methods. But advances in genomics and biotechnology have dramatically enriched the potential to manipulate the amaranth genome, especially improving the amount and availability of nutrients. In conclusion, the book covers all aspects of amaranths, including their food value, significance as vegetables and pseudo-cereals, taxonomy, phylogeny, germplasm variability, breeding behavior and strategies, cultivation practices, and variability in terms of their sexual systems. It offers a valuable resource for all students, researchers and experts working in the field of plant taxonomy and diversity. Preface Contents 1: Introduction 1.1 General 1.2 Agricultural Development and Global Food Security 1.3 Underutilised Crop 2: Pseudocereals: An Efficient Food Supplement 2.1 General 2.2 Floristic Composition of India 2.3 Pseudocereals: An Alternative Food Resource 2.4 Nutritive Value of Pseudocereals 3: Amaranths: The Crop of Great Prospect 3.1 General 3.2 Grain Amaranths: A Nutritive Supplement to Major Cereals 3.3 Different Species of Grain Amaranths 3.3.1 Amaranthus hypochondriacus L.  3.3.2 Amaranthus cruentus L.  3.3.3 Amaranthus caudatus L. 3.4 Potentiality of Grain Amaranth as Food 3.5 Vegetable Amaranths 3.6 Species of Vegetable Amaranths 3.6.1 Amaranthus tricolor L. 3.6.2 Amaranthus blitum L. 3.6.3 Amaranthus dubius L. 3.6.4 Amaranthus cruentus L. 3.6.5 Amaranthus viridis L. 3.6.6 Amaranthus graecizans L. 3.7 Nutritive Value of Vegetable Amaranths 3.8 Uses of Amaranths 3.8.1 Uses of Vegetable Amaranths 3.8.2 Uses of Grain Amaranths 3.9 Culinary Properties of Amaranths 3.10 Bioactive Components and Medicinal Properties 3.11 Weed Amaranths 4: Infrageneric Classification of Amaranths 4.1 General 4.2 Synopsis of Infrageneric Classifications of Amaranths 4.2.1 Amaranthus Subgen. Acnida Aellen ex K.R. Robertson 4.2.2 Amaranthus Subgen. Amaranthus 4.2.3 Amaranthus Subgen. Albersia Grenier & Godron 4.3 Infrageneric Classification After the Modification by Mosyakin and Robertson (1996) 4.3.1 Amaranthus Subgen. Acnida (L.) Aellen ex K. R. Robertson 4.3.2 Amaranthus Subgen. Amaranthus 4.3.3 Amaranthus Subgen. Albersia 4.4 Provisional Key to Some Edible Species of Amaranthus 5: Taxonomy and Phylogeny of Grain Amaranths 5.1 General 5.2 Morphological Approach in Solving Taxonomic Disputes 5.3 Biochemical and Molecular Approach in Understanding Systematics and Taxonomy 5.4 Cytogenetical Approach in Understanding Species Relationship 5.5 Taxonomic Delimitation in Vegetable Amaranths 5.6 Key to the Varieties of Amaranthus tricolor L. 5.7 Taxonomic Delimitation in Weed Amaranths 5.8 Different Phylogenetic Concepts on Grain Amaranths 6: Weed and Herbicide Resistance 6.1 General 6.2 Resistance to Different Types of Herbicides 6.2.1 Resistance to Photosystem II Inhibitors 6.2.2 Resistance to Acetolactate Synthase (ALS) Inhibitors 6.2.3 Resistance to Protoporphyrinogen Oxidase (PPO) Inhibitors 7: Distribution and Maintenance of Amaranth Germplasm Worldwide 7.1 General 7.2 Germplasm Collection Centres in the World 7.3 Genome Resource Development of Amaranthus 8: Breeding of Amaranths 8.1 General 8.2 Breeding Behaviour in Amaranths 8.3 Objectives in Amaranth Breeding 8.4 Conventional Breeding by Selection 8.5 Hybridisation and Heterosis in Amaranths 8.6 Male Sterility in Amaranth Breeding 8.7 Wild Gene Pool, Landraces and Heritability 8.8 Mutation Breeding 8.9 Polyploidy in Amaranth Breeding 8.10 Genetic Engineering and Biotechnological Approach in Genetic Improvement 8.11 Genetic Transformation in Breeding Amaranths 8.12 Molecular Markers and Genome Research for Using Genetic Resources in Plant Breeding 8.13 Molecular Breeding in Amaranths 8.14 Plant Tissue Culture Techniques in Amaranth Breeding 9: Evolution of Sexuality in Amaranths 9.1 General 9.2 Trend of Sexuality in Plants 9.3 Sexuality in Amaranths 10: Cultivation of Amaranths 10.1 General 10.2 Seed Dormancy and Seed Viability of Amaranthus 10.3 Agroclimatic Condition for Cultivation of Amaranths 10.3.1 Climate 10.3.2 Soil 10.3.3 Temperature 10.3.4 Rainfall 10.3.5 Day Length 10.4 Cultivation Practices 10.4.1 Sowing of Seeds 10.4.2 Seedling Growth and Interculture 10.4.3 Manuring 10.4.4 Obstacles in Productivity in Grain Amaranths 10.4.5 Harvesting 10.4.6 Pests and Diseases 11: Future Prospects in Amaranth Research Appendices Appendix I Appendix II References