Core Ideas Pearl millet and cowpea intercrop production is important in the Sahel. Inadequate nutrient supply constrains crop growth. Pearl millet sole crop nutrient response information is applicable for intercropping. Application of N and P to intercrop compared to sole crop has more profit potential. In the Sahel, crop production is dominated by pearl millet [Pennisetum glaucum (L.) R. Br.] cropping systems including intercropping with cowpea [Vigna unguiculata (L.) Walp]. The research objectives were to determine pearl millet sole crop (PMSC) and intercrop nutrient response functions, profit opportunities from fertilizer use, and a means of relating intercrop to PMSC response. Pearl millet–cowpea trials were conducted in Niger and Mali. The treatment structure was an incomplete factorial with five, four, and four levels of P, N, and K, respectively. Response functions were determined for intercropping with cowpea yield converted to a pearl millet grain yield equivalent for ratios of cowpea to pearl millet grain value (CpPm) ranging from 1 to 5 kg kg−1. Response functions were also determined in consideration of fodder value. A method of adjusting PMSC response coefficients with CpPm as the independent variable was developed for determination of intercrop response functions. Yields and responses to nutrients were low but adequate for profitable N and P use. Value of intercrop production ranged from 50 to 125% more compared with PMSC for CpPm of 2 and 4, and the respective response to 10 kg ha−1 P was 28 and 135% more with intercrop. Consideration of fodder added 23% to the yield value. Application of N and P for intercrop compared with PMSC production has much more profit potential. The ability to apply PMSC functions in determination of pearl millet–cowpea responses to applied nutrients offers a means to improve fertilizer use for the intercrop.

There are several hurdles to ensure sustainable seed production and consistent flow of improved legume varieties in sub‐Saharan Africa (SSA) and South Asia (SA). The unreliable demand, autogamous nature of most of the grain legumes, and slow variety replacement rate by smallholder farmers do not provide strong incentive for private seed companies to invest in legume seed business. Unless a well thought‐out and comprehensive approach to legume seed delivery is developed, current seed shortages will continue, eroding emerging market opportunities. The experiences reported here are collated through a 10‐year partnership project, the Tropical Legumes in SSA and SA. It fostered innovative public–private partnerships in joint testing of innovative market‐led seed systems, skills and knowledge enhancement, de‐risking private sector initiatives that introduced in new approaches and previously overlooked entities in technology delivery. As new public and private seed companies, individual seed entrepreneurs and farmer organizations emerged, the existing ones enhanced their capacities. This resulted in significant rise in production, availability and accessibility of various seed grades of newly improved and farmer demanded legume varieties in the target countries.

Many cowpea varieties (Vigna unguiculata L. Walp) have been proposed by research in Mali. None of these varieties were investigated for their symbiotic potential in terms of root nodulation and mycorrhizal infection. An experiment was conducted at Cinzana Research Station, from 2007 to 2009 with an objective to identify a cowpea variety with high symbiotic potential which may improve millet/cowpea cropping global production. Randomized complete block (RCBD) design with a factorial combination of 3 cowpea varieties (IT89KD-374, CZ1-94-23-1, and CZ11-94-5C) and 2 cropping systems (millet/cowpea intercropping and cowpea-millet rotation) was used. On farm test was conducted to evaluate CZ11-94-5C and IT89KD-374 nodulation performance. Cowpea variety CZ11-94-5-C had the highest nodule number and nodule weight. Millet/cowpea alternate rows intercropping (1/1), only, had a significant influence on cowpea root infection rates by mycorrhizae, on the 45th day after emergence. IT89KD-374 gave the best cowpea grain yield (1540 kg ha −1 ) in sole crop. The highest millet grain yield (1650 kg ha −1 ) was obtained under CZ11-94-5C-millet rotation. Farmers' fields assessments results confirmed CZ11-94-5C performance on research station. The CZ11-94-5C cowpea variety needs to be more characterized.

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