Yield Improvement in Temperate Maize is Attributable to Greater Stress Tolerance.pdf

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1、YieldImprovementinTemperateMaizeisAttributabletoGreaterStressToleranceM.Tollenaar*andJ.WuABSTRACTtoseparate,asgenotype3environmentinteractionisAretrospectiveanalysisofthephysiologicalbasisofgeneticyieldaprominentfeatureofyieldimprovementinmaize.improvementmayprovi

2、deanunderstandingofyieldpotentialandGenotype3environmentinteractioneffectsongrainmayindicateavenuesforfutureyieldimprovement.Rateofyieldyieldarealmostalwayssignificantforcomparisonsofimprovementofmaize(ZeamaysL.)hybridsinOntario,Canadahasolderandnewermaizehybridse

3、valuatedundertwoorbeen»1.5%yr21duringthelastfivedecades.Comparisonofshort-moredifferentenvironmentalconditions.Duvick(1984)seasonhybridsrepresentingyieldimprovementfromthelate1950sshowedthatdifferencesingrainyieldbetweenoldertothelate1980sshowedthatgeneticyieldimp

4、rovementwas2.5%andnewerhybridswereafunctionofplantpopulationperyearandthatmostofthegeneticyieldimprovementcouldbedensity.Differencesbetweenhybridsweresmallatlowattributedtoincreasedstresstolerance.Differencesinstresstolerancebetweenolderandmorerecenthybridshavebee

5、nshownforhighplantpopulationdensityandbecamegreaterasplantplantpopulationdensity,weedinterference,lownighttemperaturespopulationdensityincreased.Wehaveshownthataduringthegrain-fillingperiod,lowsoilmoisture,lowsoilN,andamorerecenthybridwasinfluencedlessbyweedinterf

6、er-numberofherbicides.Yieldimprovementistheresultofmoreeffi-encethananolderhybridina5-yrfieldstudyconductedcientcaptureanduseofresources,andtheimprovedefficiencyininOntario(Tollenaaretal.,1997).Incontrast,differ-resourcecaptureanduseofnewerhybridsisfrequentlyonlye

7、videntencesingrainyieldbetweenthetwohybridswerenotunderstress.Improvedresourcecapturehasresultedfromincreasedsignificantwhenthetwohybridsweregrownunderopti-interceptionofseasonalincidentradiationandgreateruptakeofnutri-malbelowgroundconditions(i.e.,hydroponically)

8、intheentsandwater.Theimprovedresourcecaptureisassociatedwithincreasedleaflongevity,amoreactiverootsystem,andahigherratiofield(Nissanka,1995).Resultsindi