Panicle Architecture of Rice and its Relationship with Grain Filling

Description

This book shows the importance of rice for human consumption. It focuses on the rice panicle, its morphology and characteristics. High genetic diversity of rice has been economically profitable for mankind; the crop provides food calories to half of the human race on earth and because of its adaptability to diversified and unstable ecological conditions, the plant has an asynchronous flowering system in the panicle. The International Rice Research Institute has a collection of panicles with numerous branching phenotypes and lengths varying from 10 to 43 cm. Due to the heterogeneous architecture, grain filling depends on the position of the spikelet within a panicle. Spikelets on apical branches fertilize early and fill faster compared to their basal counterparts and therefore, individual grain weights of panicle vary widely. The discrepancy in grain filling between spikelets changes with panicle architecture but the relationship of variation in individual grain weight with panicle architecture has not been studied. Spikelet number has increased highly in the newly developed rice cultivars, but it has no benefit accrued on grain filling and yield. This book is recommended for students, researchers and teachers working in this field of expertise. Preface Contents Chapter 1: Importance of Rice as Human Food Introduction Rice Is Unique Rice in Different Parts of the Globe Rice for Food Security Origin and Biodiversity Dissemination of Rice Demand for More Production from Rice Lands Increase in Rice Production and Consumption Breaking the Yield Frontier of Rice Measurement of Yield Potential of Rice Method 1 Assumptions Calculation Method 2 New Calculations for Yield Potential Low Yielding Traditional Rice The First Approach to Improve Yield Potential New Plant Type Rice The Second Approach to Improve Yield Potential Demerits of Hybrid Rice Phenotypic Modification of Rice with the Progress of Time Salient Features of Different Rice Cultivars Traditional Rice Semidwarf High Yielding Rice New Plant Type Rice Hybrid Rice Super Rice References Chapter 2: Botany of Rice Plant Taxonomy of Rice Plant Karyotype of the Rice Genome Characteristics of the Rice Plant Morphology of Rice Plant Vegetative Phase Reproductive Phase Organs of the Rice Plant Root System Shoot System Tillering Leaf Leaf-Sheath Lamina Auricles Panicle Structural Organization Spikelet Rice Grain Grain Yield Grain Yield Components References Chapter 3: Ontogeny of Organ Development in Rice Plant Vegetative Stage and Leaf Development Phaseic Development Primordium Development Formation of Terminal Spikelet Staging of Panicle Development Booting Stage Heading Stage Anthesis (Flowering) Events of Anthesis The Culmination of the Reproductive Stage Genes Involved in Panicle Organogenesis References Chapter 4: Fertilization and Seed Development in Rice Dehiscence of Anther Pollination Germination of Pollen Fertilization First Fertilization Second Fertilization Embryo Development Endosperm Development Nuclear Stage Cellular Stage Differentiation and Development of Endosperm Cells Aleurone Layers Parenchymatous Tissue for Storage of Starch Storage of Food Reserve Ripening Phase Seed of Rice Parts of Rice Grain and their Composition Hull Pericarp Seed Coat Endosperm Chemical Composition of Rice Grain References Chapter 5: The Cellular Basis of Rice Seed Growth Phases of Seed Growth Cell Cycle Types During Endosperm Development Endoreduplication Functions of Endoreduplication Cell Cycle Regulators Endoreduplication in Rice Seed Programmed Cell Death (PCD) References Chapter 6: Genetic Analyses of Floral Development on Rice Panicle Spikelet Development Floret Development Genetic Mechanism of Flower Development MADS-Box Genes of Rice Spikelet Lemma and Palea Development Lodicule Development Stamen Development Abnormalities of Megagametophyte Development References Chapter 7: Diversity of Panicle Architecture and Traits Influencing Grain Filling The Uniqueness of Rice Biodiversity Diversity of Panicle Architecture Determination of Branch and Spikelet Number in Panicle The Difference in Termination Mode of Rachis and Branch Meristems Identification of QTLs for Grain Yield Cumulative Genes QTLs for Yield Components Analyses of Population Structure Molecular Genetics of Panicle Meristems Regulation of Panicle Architecture Using Genetic Mutants APO, DEP, TAW, and LAX Genes FZP Gene Cytokinin Oxidase/Dehydrogenase Gene Wealthy Farmer’s Panicle Genes Controlling Panicle Length QTLs for Panicles Per Plant QTLs for Tiller Number QTLs for Grain Weight QTLs for Grain Size References Chapter 8: Change of Panicle Architecture During Domestication Domestication Domestication Syndromes Shape of Panicle Relationship of Panicle Architecture with Grain Filling Characteristics Genotype and Environment Interaction Determines Architectural Variation Modification of Panicle Architecture for Improved Grain Filling High Panicle Spikelet Number for High Yield Relationship of Panicle Architecture with Grain Filling High Spikelet Laxity Associated with Yield Loss References Chapter 9: Physiology of Variation in Individual Grain Weight of Rice Panicle Grain Filling in Rice Spikelet Heterogeneity of Spikelet Development The Difference in the Growth of Superior and Inferior Spikelets Quality Variation of Individual Grains Assimilate Partitioning Assimilate Pool Is High in Inferior Spikelets Inter-Spikelet Dominance in Grain Filling Pathway of Assimilate Transport in Rice Caryopsis Movement of Solutes Movement of Assimilates and Water in Developing Caryopsis The Function of the Pericarp in Assimilate Transport Bulk Flow of Solutes Irrespective of the Concentration Gradient Sucrose Transporter Role of a Turgor Homeostat in Rice Caryopsis References Chapter 10: Enzymes Controlling Starch Biosynthesis Sub-Optimal Sink Strength Undermines Grain Filling Starch Biosynthesis Begins with the Entry of Phloem Sucrose Synthesis of Grain Starch Enzymes for Starch Biosynthesis Entry of Sucrose into Starch Biosynthesis Pathway Sucrose Synthase ADP-Glucose Pyrophosphorylase (AGPase) Starch Synthase Starch Branching Enzyme (BE) Expression Profile of the Genes Controlling the Activity of Starch Biosynthetic Enzymes Sucrose Synthase Gene Expression ADP-Glucose Pyrophosphorylase Gene Expression Starch Synthase and Starch Branching Enzyme References Chapter 11: Hormonal Regulation of Spikelet Development Hormones as Limiting Factor for the Disparity in Grain Filling of Spikelets Role of Hormones in Inter Spikelet Dominance Positive Regulators for Grain Growth Role of Individual Hormones Auxins Auxin Biosynthesis Auxin Transport Auxin Signaling Auxin Regulates Rice Growth and Development Auxin Response on Panicle Architecture and Grain Development Panicle Architecture Grain Development Auxin Biosynthesis Genes Gibberellins Properties of Gibberellins Biosynthesis of Gibberellins Gibberellin Action Expression of sd1 Allele GA-regulated Gene Promoting Cell Elongation Gibberellin Effects on Rice Spikelet Development Cytokinins Properties and Structure of Cytokinins Cytokinin Biosynthesis in Rice Isopentenyl Transferase (IPT) Gene KNOX1 Transcription Factor for IPT Activity LONELY GUY Genes Cytokinin Oxidase (CKX) Gene Cytokinin Signal Transduction Cytokinin Response in Rice CLV Pathway Genes Controlling Cytokinin Abundance of Rice Genetic Mutations Regulating Cytokinin Biosynthesis APO 1 Allele DEP 1 Allele WFP Allele Cytokinin Effects on Grain Filling of Rice Abscisic Acid (ABA) Introduction Chemical Structure and Biosynthesis of Abscisic Acid ABA Signal Transduction in Plant Cell First Pathway Second Pathway ABA Regulates the Growth and Development of Rice Panicle ABA Improves the Activities of Endosperm Starch Synthesizing Enzymes Endogenous ABA Biosynthesis High in Superior Spikelets ABA Sucrose Synergy Regulates Endosperm Starch Synthesis ABA Interacts with Cytokinin, Auxin, and Ethylene Ethylene Introduction Chemical Structure Ethylene Synthesis and Breakdown Ethylene Signaling Dynamics of Ethylene Production During Rice Panicle Development Ethylene Controls Spikelet Development Boot ethylene Infringes Pericarp Functions Ethylene Production Underscores Yield Barriers Ethylene Perception Induces Over-Expression of Its Signal Transducers Ethylene is a Retrograde Signal for Endosperm Starch Biosynthesis Ethylene Down-Regulates Expression of Genes Encoding starch Biosynthesizing Enzymes Inverse Relationship of Ethylene with Starch Synthesis The interplay of Ethylene with Other Hormones Interaction of Ethylene with Other Hormones in Different Plant Organs Ethylene Interaction with ABA and IAA Ethylene is the Second Messenger for Auxin Signal Ethylene Interaction with Polyamines During Grain Filling Chemical Structure of Polyamines Chemical Structure of Polyamine Polyamine Effects on Grain Filling Brassinosteroids Properties of Brassinosteroids Biosynthesis of Brassinosteroids Early Oxidation Pathway Late Oxidation Pathway BR-signaling Cascade Brassinosteroids and Grain Filling of Rice Gene Manipulation for Brassinosteroid Synthesis in Rice Brassinosteroid Interaction with Gibberellins Chapter 12: Effects of Environmental Stresses on Grain Filling of Rice Panicle Climate Change and Food Security Stress Effects on Panicle Morphology of Rice Genes/QTLs for Stress Tolerance Drought Tolerance Flooding Tolerance Salinity Tolerance Hormone Homeostasis Under Perturbed Environment References Chapter 13: Designer Rice in Quest of High Grain Filling The Gap Between Potential and Actual Yields Manipulation of Panicle Architecture Spikelet-Specific Grain Filling Change of Panicle Architecture in Rice Antiquity Designer Rice Panicle Thematics for Architectural Changes Spikelet Development Pre-Ordained in the Early Reproductive Phase Changes of Hormonal Balance in Transitional Stages Hormones for Organ Differentiation Manipulation of Hormones FZP Controlling Meristem Identity Promotion of Higher-Order Branching Change Over to the Indeterminate Pattern Homogeneity in Secondary Branching of Primary Branches Cylindrical Panicle Architecture for Designer Rice Designing Panicle with Multi-Floret Spikelets References