Proportions of morphological fractions of oats (Avena sativa L.) as affected by variety and growth stage

摘要

nbsp;Thispaperpresentsrelativeproportionsofmorphologicalfractionsof20oats(AvenasativaL.)varietiesharvestedatdifferentgrowthstagesatHoletta,centralhighlandsofEthiopia.Onaveragetheproportionofleafbladedecreasedfrom52.2to15.6%withparallelincreaseintheproportionofstemfrom19.4to57.6%asgrowthadvancedfrombootstagetograinmaturitystage.Theaverageproportionofleafsheathdecreasedfrom28.4to18%asgrowthadvancedfrombootstagetothesoftdoughstage,butittendedtoregainatgrainmaturitystage(26.8%).Thepanicleproportionwasfoundtoberelativelystableincreasingonlyby4%unitswithadvanceingrowthfromheadingtothesoftdoughstage.nbsp;Thedifferentvarietiesalsoexhibitedconsiderabledifferenceswithrespecttotheproportionofmorphologicalfractionsoverthedifferentgrowthstages.Takingthephysiologicalmaturityforforageharvestofthesoftdoughstageasareference,theoatsvarietiesPI#8211;5800,CI#8211;8251andGrayalgeriswerefoundtocontainahigherproportionofleafintheirdrymatter(DM)thantheothervarieties,whiletheoatsvarietiesPI#8211;244480,SRCPX80Ab2291andSRCPX80Ab2806hadcomparativelyhigherproportionofstemintheirDM.nbsp;Theresultsshowedthepresenceofconsiderablevarietaldifferencesintheproportionofmorphologicalfractionstherebysuggestingthepossibilityofimprovingforageproductioninoatsthroughproperexploitationofthevarietaldifferences.