YIELD FORMATION AND YIELD STRUCTURE OF WINTER OILSEED RAPE (BRASSICA-NAPUS L) .2. COMPARISON OF PARENTAL LINES AND THEIR F1 GENERATIONS AND F2 GENERATIONS

Hybrids of winter oilseed rape are now under development. This study was conducted to compare parental, F1- and F2 generations for yield structure and several important yield formation traits. Fourteen randomly chosen European winter oilseed rape (Brassica napus L.) breeding lines and cultivars were crossed in an uncomplete factorial design. The F2-generations were produced by selfing each several plants of all 21 F1- generations. Parental, F1- und F2 generations were tested at four environments under north german conditions. Mean heterosis in seed yield amounted 16.7 %. Furthermore, heterosis was detected for seeds per silique, seeds per area, biomass before winter, LAI before winter, biomass at anthesis, LAI at anthesis, biomass at maturity and harvest index but not for individual seed weight and number of branches. Comparing the genotypic correlation coefficients for parental, F1- and F2 generations, they were almost consistent. Seed yield was correlated to siliques/area, seeds/area, biomass at anthesis and harvest index. With the exception of biomass the gca-effects were more important than the sca-effects.