Influence of within-row spacings on distribution patterns of yield components in cowpeas

Abstract

Yield distribution patterns of cowpeas ( Vigna unguiculata (L.) Walp.) cultivar ‘California Blackeye No. 5’ were evaluated at 5, 10, 15 and 20 cm within-row spacings during spring and fall seasons of 1986 near Fort Pierce, FL. Yield components were partitioned by origin, main stem or branches, and by node and seed weight into 4 nodal groups 1–4 with node numbers 1–4, 5–8, 9–12 and 13–18 nodes, respectively, with Node 1 equal to the cotyledonary node. Pod and seed number and weight originating from branches, main stem or totals per plant increased linearly with decreasing within-row spacing. Seeds per pod and seed size (g seed −1) were unaffected by within-row spacing, however, a higher seed number occurred in pods originating from the main stem as compared with branches. Yield productivity per reproductive node increased with wider within-row spacings. The majority of the total seed weight originated from branches and main stem in nodal Group 1. Plants spaced 5 or 10 cm apart had a lower percent seed weight from branches in nodal Group 1 than plants spaced 15 or 20 cm apart. Averages of 10.3 and 1.7% of the total seed yield originated in nodal Groups 3 and 4, respectively. A higher percent seed weight originated from the main stem in plants spaced at 5 or 10 cm apart as compared with plants spaced 15 or 20 cm apart. The data suggest that distribution patterns of yields or plant architecture can be differentially influenced by plant density. Breeding for improved branch yield productivity, particularly in nodal Group 2, may ultimately increase total seed yields, regardless of plant density.