Responses of cowpea (Vigna unguiculata (L.) Walp.) and mung bean (Vigna radiata (L.) Wilczek) to irrigation

Summary Cowpea and mung bean were subjected to three irrigation schedules during summer dry months (May–June). In general, cowpea had higher rates of net photosynthesis (P_n,Figs. 1, 2), dark respiration (R_d,Table 1), absorption of photosynthetically active radiation (PAR, Table 2), and growth (Fig. 7) than mung bean. Mung bean reflected more PAR and maintained a slightly cooler canopy than cowpea (Table 2). Moisture stress decreased P_n, R_d,absorption coefficient of PAR, evaporative cooling and growth in both the species. However, the reductions in P_nrates of stressed leaves were more than the decreases in R_d.Restoration of water supply to stressed cowpea resulted in a more rapid recovery of growth as compared to mung bean.