Water-conservation Traits To Increase Crop Yields In Water-deficit Environments: Case Studies (springerbriefs In Environmental Science)

This volume explores specific approaches that have shown to result in crop yield increases. Research on the physiological understanding of these methods has led to the development of practical applications of plant breeding approaches to genetically improve crops to achieve higher yields. Authoritative entries from crop scientists shed new light on two water-conservation traits: one that is based on an initiation of the decrease in transpiration earlier in the soil drying cycle, and the second that is based on a sensitivity of transpiration rate under high atmospheric vapor pressure deficit that results in partial stomatal closure. Both these approaches involve partial stomatal closure under well-defined situations to decrease the rate of soil water loss. Readers will be able to analyze the circumstances under which a benefit is achieved as a result of the water-limitation trait; and key discussion points in the case studies presented will help answer questions such as what species, which environments, how often will yield be benefited for various crop species? Contributions also review the genetic variation for these two traits within each crop species and the physiological basis for the expression of these traits. Preface 5 Contents 6 Contributors 8 Chapter 1: Introduction 10 References 12 Chapter 2: Early Partial Stomata Closure with Soil Drying 13 2.1 Background for Stomatal Response to Soil Drying 13 2.2 Consequences of Early Stomatal Closure 15 References 17 Chapter 3: Limited-Transpiration Rate Under Elevated Atmospheric Vapor Pressure Deficit 18 3.1 Introduction 18 3.2 Benefit of Limited-Transpiration Trait 19 3.3 Genetic Variation 20 3.4 Mechanistic Basis for Limited Transpiration 22 References 22 Chapter 4: Soybean 24 4.1 Water Conservation with Soil Drying 24 4.2 Water Conservation by Sensitivity to Vapor Pressure Deficit 26 4.2.1 Slow-Wilting Phenotype 26 4.2.2 Observations of Water-Limitation Trait 26 4.3 Aquaporin Involvement 27 4.4 Genetic Variation for Limited-Transpiration Trait 29 4.5 Germplasm Release 30 4.6 Extent of Yield Advantage 30 References 32 Chapter 5: Peanut 34 5.1 Water Conservation with Soil Drying Cycle 34 5.2 Water Conservation with Sensitivity to Vapor Pressure Deficit 35 5.2.1 Observations of Water-Limitation Trait 35 5.2.2 Hydraulic Conductivity and Aquaporins 37 5.2.3 Response to the Environment 38 5.3 Inheritance of TRlim Trait 38 References 40 Chapter 6: Chickpea 41 6.1 Transpiration Response to Soil Drying 42 6.2 Transpiration Response to Increasing Vapor Pressure Deficit 43 6.3 Hydraulic Limitation 45 6.4 Aquaporin Mediated Water Transport Pathway 47 6.5 Water Extraction During Growing Season 48 References 50 Chapter 7: Lentil 52 7.1 Water Conservation by Sensitivity to Soil Drying 53 7.2 Water Conservation by Sensitivity to Vapor Pressure Deficit 54 7.3 Extent of Yield Advantage from the Water-Saving Traits 55 References 58 Chapter 8: Maize 59 8.1 Decrease in Transpiration with Progressive Soil Drying 59 8.2 Transpiration Sensitivity to Vapor Pressure Deficit 60 8.2.1 Influence of High Temperature 61 8.2.2 Hydraulic Conductivity and Aquaporin Inhibitors 63 8.2.3 Extent of Yield Advantage 64 References 66 Chapter 9: Sorghum 68 9.1 Crop Responsiveness to Soil Drying 69 9.1.1 Sorghum Growth and Transpiration Response to Soil Drying 69 9.1.2 Simulated Impact on Grain and Stover Yield 69 9.2 Plant Responsiveness to Atmospheric Drought (Vapor Pressure Deficit) 69 9.2.1 Limited Transpiration Rate Under High Vapor Pressure Deficit in Sorghum 69 9.2.1.1 Environmental Conditions Affect Plant Responsiveness to VPD 72 9.2.2 Plant Processes Underlying Transpiration Responsiveness: Hydraulics and Aquaporin Expression 72 References 73 Chapter 10: Pearl Millet 75 10.1 Water Conservation with Soil Drying 76 10.2 Water Conservation from Sensitivity to Vapor Pressure Deficit 77 10.3 Water Transport Pathways 78 10.4 Leaf Abscisic Acid (ABA) Regulation for Low TR 80 10.5 Gene Expression of Water-Saving Traits 80 10.6 Effects of Water Conservation on Yield 83 References 83 Chapter 11: Wheat 86 11.1 Water Conservation in Response to Progressive Soil Drying 87 11.2 Water Conservation in Response to Increasing Atmospheric Vapor Pressure Deficit 87 11.2.1 Diversity in Transpiration Response to VPD in Wheat and Relationship with Yield Performance under Drought 87 11.2.2 Involvement of Roots in Restricted TR in Response to VPD 89 11.2.3 Genetic Basis for Water Conservation in Response to VPD 91 References 92 Index 94 Front Matter....Pages i-x Introduction....Pages 1-3 Early Partial Stomata Closure with Soil Drying....Pages 5-9 Limited-Transpiration Rate Under Elevated Atmospheric Vapor Pressure Deficit....Pages 11-16 Soybean....Pages 17-26 Peanut....Pages 27-33 Chickpea....Pages 35-45 Lentil....Pages 47-53 Maize....Pages 55-63 Sorghum....Pages 65-71 Pearl Millet....Pages 73-83 Wheat....Pages 85-92 Back Matter....Pages 93-95