ABSTRACT

Three field experiments on three vegetable cowpea varieties with contrasting growth habits were conducted at the Eastern Farm of Michael Okpara University of Agriculture, Umudike. LAI and vine length were the evaluated vegetative parameters, while number of fresh pods/plant, weight of fresh pods per plant, fresh pod yield number of seeds/pod, 100-seed weight and seed yield, were the evaluated reproductive parameters. Experiment one conducted in 2007 and 2008 was laid out with split-plot design, while experiments two and three conducted in 2006 and 2007 were with randomized complete block design (RCBD). Experiment one assessed the response of some vegetable cowpea varieties to planting dates. The evaluated varieties were IT8ID-1228- 14 (erect), IT8ID-1228-12 (semi-erect) and FARV-13 (climbing variety), while sowing dates were: May, June, July and August. Experiment two evaluated the response of vegetable cowpea varieties to the rates of P and K fertilizers, while experiment three measured the response of some vegetable cowpea varieties to planting density. The result from experiment one, showed that the erect (IT8ID-1228-14) and semi-erect (IT8ID-1228-12) varieties yielded higher than the climbing variety (FARV-13). The month of May seemed most favorable for vegetable cowpea cultivation, while August planting gave the poorest pod and grain yields. Experiment two revealed that all parameters were increasing significantly as the rates of P and K fertilizers were equally increasing. IT8ID- 1228-14 (erect) and IT8ID-1228-12 (semi-erect), yielded highest at the peak of phosphorus 30 kg P205/ha and Potassium 45 kg K20/ha fertilizers application. Interaction equally revealed that combined application of P and K, seemed better than sole application because of observed complement between the two. Experiment three indicated that higher fresh pod plant were obtained from 1T8ID-1228-14 and IT8ID-1228-12 at 50cm x 40cm (50,000 plants/ha) and 50x30cm (66,660 plant/ha) respectively, while 50x10cm (200,000 plants/ha) gave the highest quantity of seeds and fresh pods yield. Manipulation of vegetable cowpea for growth and yield, therefore involves the adoption of recommended sowing dates of May, June or July, sowing density of 200,000 plants! ha, application of P at 30kg P205/ha or of K at 45 kg k20/ha fertilizers and planting of IT81D — 1228 — 14 (erect) or IT81D — 1228 — 12 (semi- erect) varieties.