Thisbookisconcernedwiththewaysinwhichcropsmightbedevelopedfor
soilsthatare, atthepresent, agriculturallyunproductivebecauseofexcesses
and/ordeficienciesofcertainminerals. Wehaveconcentratedonsoils, rather
thanonenvironmentalconditionsthatlimitproductivity, sincetherehavebeen
anumberofrecenttextsdealingwithtopicssuchasdroughtandtemperature.
Theaimisthatthoseworkingtoderivecropsforgrowthontheseproblem
soilsshouldbeawareofthemanydiverseavenuesthatareavailable. These
comefromthedisciplinesofplantbreeding, geneticsandphysiology, andthe
interfacesthataredevelopingbetweenthem. Thebackground,
therequirementstofeedtheprojectedincreaseinhuman population,
issetoutintheintroductorychapter. Thenextfivechaptersthen
dealwiththeapproachestocropimprovement: themeritsofaconventional
breedingprogramme, theimportanceofphysiologicalcharactersinmaking
selections, theuseofinvitrotechniques, ofcytogenetics, andthevalueof
developingnativeplantsintocropsintheirownright. Althoughsalinityisoften
usedasanexample, reflectingtheresearchinterestsofmanyoftheauthors, the
methodsandapproachesdescribedhavemuchwiderapplicability.Twochap-
tersarethenconcernedmorespecificallywithbreedingfortolerancetoother
metaltoxicitiesandwithdeficienciesandtoxicitiesofmicronutrients.
Finally, in theconcludingchapter,
wesummariseandfindcommongroundbetweenthe
differentapproachesandpointsofview. Brighton, April1994 ANTHONYR. YEO
TIMOTHY J. FLOWERS Contents Chapter1 Introduction:
WorldPopulationandAgriculturalProductivity T. 1. Flowers 1. 1
HowManyPeopleAreThere? . 1 1. 2 AgriculturalRequirements. . 2 1. 2. 1
FoodRequirements...2 1. 2. 2 FoodSupply...4 1. 3
Population-CarryingCapacity...5 1. 4 HowMuchLandIsThere? . 6 1. 5
IncreasingFoodProduction . 7 References...9 Chapter2
ConventionalPlantBreedingforTolerancetoProblemSoils C. N. ChaubeyandD.
Senadhira 2. 1 ScreeningTechniques . 11 2. 2
VariabilityinToleranceforSoilStresses . 14 Rice . 15 2. 2. 1 2. 3
GeneticsofToleranceforSoilStresses...16 19 2. 3. 1
GeneLocationandLinkages...CorrelatedChanges...20 2. 3. 2 2. 4
Crop-Improvement . 21 2. 4. 1 Introduction...21 2. 4. 2
PureLineandMassSelection...21 2. 4. 3 HybridisationandSelection. 23 2.
4. 3. 1 PedigreeMethod...23 2. 4. 3. 2 BulkMethod...23
BackcrossBreeding...2. 4. 3. 3 26 2. 4. 3. 4 RecurrentSelection...26 2.
4. 3.5 RapidGenerationAdvanceProcedures...27 2. 4. 4
MutationBreeding...28 2. 4. 5 PolyploidBreeding. 28 2. 4. 6
HeterosisBreeding. 29 2. 5 Summary...29 References...29 VIII Contents
Chapter3 PhysiologicalCriteriainScreeningandBreeding A. R. Yeo 3. 1
Introduction...37 3. 2 ReasonsfortheUseofPhysiologicalSelection . 38 3.
2. 1 TheComplexityofTolerance...38 3. 2. 2
ImportingTolerancefromWildRelatives . 39 3. 2. 3
MeasuringStressTolerance . 40 3. 2. 4
InteractionBetweenEnvironmentalStresses...42 3. 2. 5
LimitationstotheUseofYieldasaSelectionCriterion...42 3. 3 Salinity . 43
3. 3. 1 BasicProblems...43 SaltExclusion...44 3. 3. 2 3. 3. 3
ConditionsRequiringOsmoticAdjustment. . 45 3. 3. 4
CharacteristicsNeededinSalt-TolerantPlants . 46 3. 3. 4. 1 Con
