Heterosis Estimates for Yield and Yield Components in Sunflower (Helianthus annus)

The study was carried out to determine magnitude of heterosis for six heritable traits in sunflower. Study was conducted during 2000-2003 at NWFP Agricultural University, Peshawar on a 8x8 diallel cross of sunflower to find out the extent of heterosis for parameters like head size, achene yield/plant, achene number/plant, 100-achene weight, achene yield (kg ha^-1) and oil content. Heterosis was observed for all the parameters studied. The magnitude of heterosis for different characters varied for the parameters studied and it was the maximum (32.88%) for head size and minimum (1.29%) for achene yield ha^-1. No cross combination was consistent in heterosis for all characters studied. Maternal effects were significantly visible for traits like achene number/plant, achene yield ha^-1 and oil content but not significantly visible for head size, achene yield/plant and 100-achene weight. For most of the characters except head size and achene number, heterosis was more in those cross combinations where parents were phenotypically at distance.