Abstract:

Five sunflower varieties were grown at the National Semi Arids Resources Research Institute Five sunflower varieties were grown at the National Semi Arids Resources Research Institute (NaSARRI) and on 24 farmers’ fields in the districts of Soroti, Kumi, Pallisa, Mbale, Sironko, Katakwi, Kaberamaido and Apac in Uganda, with and without fertilizers. Two commercial varieties (one hybrid called PAN 7351 imported from South Africa and one open pollinated variety called Sunfola, bred in Uganda) and three candidate hybrids (372/271, 383/271 and 404/271) developed from NaSAARI, Uganda were used. Two fertilizer application rates (N30P60 and N60P60) referred to here as midfertilizer and high fertilizer rates respectively, were compared with a no fertilizer control (N0P0). Single super phosphate (ssp) provided the phosphorous, and urea provided the nitrogen. With no fertilizer, mid-fertilizer and high fertilizer rates Sunfola yielded 344.1, 445.1 and 547.2 respectively. The NaSARRI candidate hybrid 383/271 yielded 418.4, 595.5 and 642.5 kg/acre respectively, compared to 372/271 which yielded 354.8, 552.4 and 594.0 respectively, and to hybrid 404/271 (361.1, 491.0 and 624.1 kg/acre respectively). The trend for PAN 7351 was 502.3, 668.5 and 765.2 kg/acre respectively. With the commercial hybrid PAN 7351, a 30 kg increase in Nitrogen applied, from N0 to N30 was associated with a 166.2 kg/acre increase in yield, while a 30 kg increase from N30 to N60 caused a yield increase of 96.7 kg/acre. The mid fertilizer rate was more recommendable for farmers compared to the higher one in order to optimize yield return to every unit of applied nitrogen fertilizers. But both fertilizer rates ensued big volumes of sunflower seed for the oil industry. Low buying price of Uganda Shillings 500=/kg of row sunflower prevented many farmers from realizing positive net gains from fertilizer use, especially in Sunfola, but a projected minimum buying price of 800= would have led to big net incomes among many of the farmers. RRI) and on 24 farmers’ fields in the districts of Soroti, Kumi, Pallisa, Mbale, Sironko, Katakwi, Kaberamaido and Apac in Uganda, with and without fertilizers. Two commercial varieties (one hybrid called PAN 7351 imported from South Africa and one open pollinated variety called Sunfola, bred in Uganda) and three candidate hybrids (372/271, 383/271 and 404/271) developed from NaSAARI, Uganda were used. Two fertilizer application rates (N30P60 and N60P60) referred to here as midfertilizer and high fertilizer rates respectively, were compared with a no fertilizer control (N0P0). Single super phosphate (ssp) provided the phosphorous, and urea provided the nitrogen. With no fertilizer, mid-fertilizer and high fertilizer rates Sunfola yielded 344.1, 445.1 and 547.2 respectively. The NaSARRI candidate hybrid 383/271 yielded 418.4, 595.5 and 642.5 kg/acre respectively, compared to 372/271 which yielded 354.8, 552.4 and 594.0 respectively, and to hybrid 404/271 (361.1, 491.0 and 624.1 kg/acre respectively). The trend for PAN 7351 was 502.3, 668.5 and 765.2 kg/acre respectively. With the commercial hybrid PAN 7351, a 30 kg increase in Nitrogen applied, from N0 to N30 was associated with a 166.2 kg/acre increase in yield, while a 30 kg increase from N30 to N60 caused a yield increase of 96.7 kg/acre. The mid fertilizer rate was more recommendable for farmers compared to the higher one in order to optimize yield return to every unit of applied nitrogen fertilizers. But both fertilizer rates ensued big volumes of sunflower seed for the oil industry. Low buying price of Uganda Shillings 500=/kg of row sunflower prevented many farmers from realizing positive net gains from fertilizer use, especially in Sunflower, but a projected minimum buying price of 800= would have led to big net incomes among many of the farmers.