Two field experiments were undertaken between 2008 and 2009 at the Teaching and Research Farm of the University of Agriculture,Makurdi and at the National Root Crops Research Institute Sub-Station, Otobi (both located in Southern Guinea Savanna agro ecological zone of Nigeria) to evaluate fourteen improved extra-early-and early-maturing cowpea varieties in sole and in intercropping systems. The work aimed at assessing the productivity of these cowpea varieties and competitive interactions with the maize component as well as the profitability of cowpea/maize intercropping systems. The first experiment was laid out in randomized complete block design with three replications in each of the two locations. IT04K-221-1, IT03K-316-1,IT03K-324-9,IT03K-351-1,IT00K-1217, IT98K-692, IT99K-377-1, IT03K-378-4 cowpea varieties proved superior to the Ife Brown(check) in number of pods produced per plant, dry pod weight and grain yield, and therefore were selected for further investigation under intercropping .Grain yield advantage of IT04K-221-1 over Ife Brown was370.69%.The selected cowpea varieties, along with the Ife Brown(check), were intercropped with maize in split-plot experiment laid out in randomized complete block design with three replications at Otobi for two seasons.. Intercropping depressed the number of branches per plant and the dry grain yield of cowpea but did not influence the number of pods per plant, number of seeds per pod and the pod length of cowpea. Maize grain yield reductions resulting from intercropping varied from 49.26% to 72.41%, depending on the cowpea variety. Intercrop advantages measured by land equivalent ratio, area x time equivalency ratio; land equivalent coefficient indicated that IT04K-221-1, IT03K-316-1, IT03K-324-9, IT98K-692 and IT00K-2117 proved most productive under intercropping. Competitive indices (competitive ratio and aggressivity) showed that cowpea was the more competitive component of the intercropping. Sole cowpea had a mean net benefit of-N560.00/ha, while intercropped cowpea gave a mean value of N 11330.00/ha, implying that growing extraearly-and early-maturing cowpea in sole systems would result in losses. Intercropped IT04K-221-1 produced the largest net benefit (N 42425.00/ha), while IT03K-378-4 gave the lowest (-N 16300.00/ha).

Aim:To investigate the performance of some improved sweet potato varieties obtained from the National Root Crops Research Institute (NRCRI), Umudike, Nigeria, for root yield and other yield components.

Field experiments were conducted at the National Root Crops Research Institute sub-station, Otobi, in 2006 and 2007 to assess the suitability of improved sweet potato varieties for intercropping with pigeonpea and also to determine the planting pattern and the productivity of the intercropping system. Intercropping decreased total fresh root and saleable root yields of sweet potato when mixed or row-intercropped with pigeonpea. All intercropping combinations of sweet potato varieties and pigeonpea had land equivalent ratio above 1.0, except intercropping with WA Gabolige, signifying high intercrop advantages. TIS 87/0087 produced the highest total fresh root and saleable root yields in both cropping systems, irrespective of the planting pattern used. TIS 2532.O.P.1.13 and TIS 86/00356 sweet potato varieties had comparable yields with TIS 87/0087 in both cropping systems. Pigeonpea was the more competitive component of the intercrop. Farmers showed willingness to adopt the sweet potato + pigeonpea intercropping.

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