Effects of Water Deficit on Growth, Yield and Seed Oil Content of Sunflower (Helianthus annuus L.)

Abstract

Studies  on  the effects  of  water deficit  0n  growth,yield  and  seed  oil  content  of  sunflower,  was  carried  out  by using a Stripplot  design  in  RCB  with  3  replications,   The vertical  plot  consisted  of  two two sunflower  cultivars: Pacific 33 and  Pacific 55, The  horizontal  plot consisted of  three  water stress  treatments  namely  control (T₁), plants  were watered  to  field  capacity throughout  the  experiment; water  stress  during  flower   flower  initiation(T₂): water  was  withheld  during  flower  initiation  until  wilting and  plants  were  then  rewatered, and  water  stress  during  anthesis (T₃) : water was  withheld  during  anthesis  until wiltimg   and  plants  were  then  rewatered, The  study  was  conducted  in  the  experimental  field  of  Agronomy  Department. Faculty  of Agriculture,  Kasetsart  University, Kamphaeng  Saen  campus,  Nakhon  Pathom   province  during November 2007  to March  2008. The results  indicated  that  water deficit  at  anthesis ( T₃) caused  the  greatest  reduction in stem  diameter  of  sunflower, However plant height, dry  weight  accumulation  and  seed  yield  were  not  affected  by water deficit, The  results  also  showed  that  water deficit  at both  flower  initiation (T₂) and  anthesis (T₃) had  no  effect on seed oil  content  of  sunflowers  but  altered  levels  of  some fatty  acid, especially  in Pacific  33  cultivar which  had  higher oleic acid  level  under  stress  conditions.