Abstract:
Soilfertilitydeclineisoneoftheprincipalfactorscontributingtolowproductivityof
cropsandfoodinsecurityinEthiopia.AstudywasconductedatDoyogenaWoderawiththe
aimtodeterminetheeffectofdifferentnitrogen levelsi.e.0,23,46and69kg/haNonyield
andyieldcomponentofthreebreadwheatvarieties.Afactorialapproachinrandomized
completeblockdesignwiththreereplicationswasused.Fromthedatacollectedand
analyzed,resultsshowedthatthereexistsignificantdifferenceamongthewheatvarietiesin
maturityday,plantheight,spikelength,grainsperspike,grainweightperspike,1000grain
weight,biologiqalyieldandgrainyield.Digaluwassuperiorwithplantheight,numberof
grainsperspikeandgrainweightperspikeandalsoproducinghighergrainyieldand
biologicalyieldbutstatisticallyatparwithHidassevariety.Ontheotherhand,Hidasse
varietysurpassedothervarietiesby1000-grainweight.Digaluexpressedlatematurity
whileHidasseappearedtobeearlymaturingvariety.Exceptthousandseedweight,allother
yieldanditscomponentswasincreasedwithincreasingrateofnitrogengenerally.The
interactionofwheatvarietiesandNfertilizationsignificantlyaffectedspikelength,grain
weightperspike,thousandgrainweight,grainyieldandbiologicalyield.Thecorrelation
analysisrevealedthatgrainperspike;grainweightperspike;spikelengthandbiological
yieldwerethemostimportantcontributingcharactersinthetotalvariabilityofgrainyield.
ThemaximumagronomicefficiencyofvarietieswasrecordedinDigaluwhereasminimumin
Danfecultivar.Applicationof46kg/hanitrogenobservedthemaximumagronomicefficiency
whiletheminimumagronomicefficiencywasrecordedat69kg/hanitrogenlevel.Grainyield
responseindexshowedthatDigalubelongedtonon-efficientbutresponsiveandHidasse
xii
appearedtobeefficientbutnon-responsivewhileDanfevarietyindicatedneitherefficient
norresponsive.
