Options for increasing seed yield of winter oilseed rape ( Brassica napus L.): a simulation study

Abstract

Options for increasing seed yield in winter oilseed rape were evaluated quantitatively by means of sensitivity analyses with a crop growth model. Then, crop ideotypes were designed for high-yielding winter oilseed rape under optimal growth conditions, and their relative effects on seed yield for six different locations in Western Europe were simulated. Exploration of options indicated that higher seed yields may be obtained through (in descending order of importance): (a) delayed maturity; (b) improved seed set: (c) smaller petals or apetalous flowers; (d) increased potential growth rate of individual seeds; (e) earlier flowering with retention of the duration of total growth period and (f) erect clustered pods. The results also showed that increased average seed yields can best be obtained by simultaneously increasing the average sink and source capacity for seed filling. The most promising crop type for high seed yield matures late, combines early flowering with a maximum LAI of about 3 for almost maximum light absorption and has erect clustered pods for source improvement. To take full advantage of the source, the sink has to be increased through a high rate of seed set, a large sink capacity of individual seeds, apetalous flowers or a combination of these characteristics. This crop type showed large cumulative light absorption, light-use efficiency, harvest index and potential seed yield at different locations in Western Europe. Without a delay in maturity, the potential increases in seed yield were smaller.