Organic agriculture can and should play an important role in solving future challenges in producing food. The low level of external inputs combined with knowledge on sustainablity minimizes environmental contamination and can help to produce more food for more people without negatively impacting our

Field trials were conducted during 2002 and 2003 to determine the productivity and compatibility of the cropping systems obtained from intercropping varieties of sesame (E8, PBTil and 530‐6‐1) and sunflower (Funtua, Record and Isaanka) in the humid forest–savanna transition zone which is outside the current growing areas. Intercropping did not affect the number of branches per plant, number and weight of capsules per plant, weight of seeds per plant, 1000 seed weight or seed production efficiency (SPE) of all sesame varieties in both years, except SPE in 2003. In both years, intercropping sesame with sunflower varieties significantly reduced grain yield of PBTil and E8. However, 530‐6‐1 produced grain yield similar to the monocrop when intercropped with Record and Funtua in 2002 and 2003, and Record in 2003. In both years, intercropping significantly depressed the grain yield of the three sunflower varieties because of reduction in their head diameter, head weight, number and weight of seeds per head and lower number of plants per unit area relative to their monocrops. E8, 530‐6‐1 and PBTil intercropped with the three sunflower varieties recorded land equivalent ratio values in the range of 1.13–1.37, 1.32–1.46 and 1.22–1.35, respectively. Based on competitive ratio values, E8 demonstrated the greatest ability to compensate for intercrop competition with taller sunflower varieties. It was concluded that growers can successfully cultivate sesame (530‐6‐1 and PBTil) under intercropping with sunflower in the humid forest–savanna transition zone.

Field trials were conducted during 2004 and 2005 to determine the effect of sowing seeds from plants with multiple heads and seeds from single headed plants of sunflower on seed yield, head characteristics and oil content of three widely grown open pollinated varieties (Funtua, Record and Isaanka) in the humid forest -savanna transition zone which is outside the current growing areas with a view to improving stability and sunflower productivity in this region. Seeds from multiple headed plants produced plants that flowered and matured 2-3 days later than plants from single headed plants. Apart from days to flowering in 2004, number of days to maturity and plant height were affected independently by variety and seed source factors. However, the seeds from single headed plants produced plants that recorded significantly (P < 0.01) higher head weight, head diameter, achene weight and number per head than plants from seeds of plants with multiple heads. Seed source had little effect on sunflower seed yield and oil content. However, Funtua produced significantly (P < 0.05) high seed yield (1956.0 kg ha −1 ± 76.06) when seeds from plants with multiple heads were sown, while Isaanka recorded comparatively high seed yield from seeds of plants from either multiple (1221.0 kg ha −1 ± 165.90) or single heads (1388.0 kg ha −1 ± 135.84) and Record (1201.0 kg ha −1 ± 96.97) when seeds from single headed plants were sown. Therefore, it is recommended that prospective sunflower growers who wish to cultivate Isaanka, can sow seeds from either the multiple or single head and preferably the multiple head for Funtua, and single head for Record.

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There is a need to develop sustainable and productive cropping systems for edible vegetable oilseeds in tropical Africa.