Two field experiments were. carried out at the Experimental Station, Fac. of
Agric., Mansoura Univ. during the growing seasons of 1997/98 and 1998/99. This
investigation was aimed to evaluate heterosis estimations of different seed yield, its
components and some related traits in some canola parents and their hybrids under
different plant population density. The genetic materials used in this investigation
included four lines of canola representing a wide range of diverse origins. These four
lines are Drakkar, Fido, Serw 4 and Serw 6. These four parental genotypes were
made according to a complete diallel matting design to produce 6 Fl hybrids and 6 Fl
reciprocals: A split plot design with three replicates was used to evaluate canola
parents and their hybrids at different plant population density. It could be summarized
the main findings as follows: The cross combination between S 33 X S 30 also recorded the highest
heterosis values over the mid-parents for leaf area index (LAI), number of siliqua per
plant, seed yield per plant and seed yield (Ufed) in most of cases. While, the cross
combination S 33 X S 34 showed the best cross for oil percentage. Also, the F_1r
hybrid S 33 X S 30 recorded the highest heterosis value over better parent for seed
yield per plant and seed yield (Ufed). The Fl hybrid S 30 X S 34 recorded the highest
values of percent heterosis over better parent for number of primary branches per
plant and 1000 seed weight. In the case of oil percentage, the cross combination
between S 33 X S 34 recorded the best heterosis values over better parent. It could be concluded that maximum seed yield of canola at Dakahlia district
could be gained by planting the F_1r hybrid S 33 x S 30 at dense plant population of 20
plants/rrr' (84000 plants/fed).