1 Subtropical Agriculture and Environments 67:1-12.2016 Pigeon pea (Cajanus Cajan) is a perennial legu- minous crop and one of the most important pulses in the dry areas of eastern Kenya (Kimani et al., 1994). The crop is grown in regions where moisture deficien- cy is a constraint to other crop production or locations where annual rainfall amounts are less than 1,000 mm (Okoko et al., 2002). The eastern region of Kenya is the most important pigeon pea production area and accounts for approximately 90% of total crop produc- tion in Kenya. The deep tap root system allows the plant to tolerate drought and utilize residual moisture during dry seasons and drought-prone regions of east- ern Kenya and other parts of the world (Gwata and Silim, 2009). It is estimated that the yield potential of pigeon pea grain is approximately 1 ton ha -1 , and its market potential is increasing. Because of its nutritious content, pigeon pea is often used to supplement cereal- based diets and consequently, it is used extensively by many smallholder farmers in Kenya. It has been documented that nitrogen fixation rate by pigeon pea may be in excess of 235 Kg N ha -1 and its assimilation per unit of crop biomass exceeds that Yield components of vegetable pigeon pea cultivars J. D. Ojwang 1 , R.O. Nyankanga 2 , O.M. Olanya *3 , D.O. Ukuku 3 , and J. Imungi 4 1 Solidaridad (SECAEC), P.O. Box 42234 00100, Nairobi, Kenya. 2 Department of Plant Science and Crop Protection, University of Nairobi, P.O Box 30197- 00100, Nairobi, Kenya. 3 USDA-ARS, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA. 4 Department of Food Science, Nutrition and Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi, Kenya. *Corresponding author. e-mail: modesto.olanya@ars.usda.gov ABSTRACT Yield potential of twelve medium maturity vegetable pigeon pea ( Cajanus cajan) cultivars was evaluated at two locations, Kiboko and Kambi ya Mawe in eastern Kenya during 2012 and 2013 cropping years. Pigeon pea pod numbers, seeds per pod, seed mass; grain yield and shelling percentage were quantified in three replicated plots, arranged in a randomized complete block design. Significant differences ( P<0.05) in grain yield (Kg/ha) was recorded among cultivars and cropping seasons. Yield of vegetable pigeon pea cultivars varied between locations as grain weight, pod length and seed mass were greater at Kiboko than Kambi ya Mawe location. Similarly, signifi- cant (P<0.05) and positive correlation coefficients between grain yield and pods plus grain as well as shelling per- centage were recorded, indicating that this is an important variable for cultivar selection in vegetable pigeon pea. The cultivars ICEAP 00068, ICEAP 00540, ICEAP 00554, ICEAP 00902, and MZ 2/9 showed high yield potential under rain-fed conditions, while ICEAP 00902, ICEAP 00068, ICEAP 00557, ICEAP 00554 and MTHAWAJUNI had good yield response when supplemental water was applied. Under both rain-fed and supplementary water ap- plications, the yield response of the cultivars KAT 60/8, ICEAP 00068, ICEAP 00554, and ICEAP 00902 ranged from 1,315 to 4,702 Kg per hectare. Selective deployment of cultivars can greatly improve its productivity and utilization in the dry agricultural regions. Additional Index Words: Cajanus cajan, cultivars, vegetable pigeon pea, yield components, shelling percentage, eastern Kenya Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture, the University of Nairobi or Solidaridad of similar ones not mentioned. ______________________________________________