THE EFFECT OF INTRASPECIFIC COMPETITION ON GROWTH AND PRODUCTIVE CHARACTERISTICS OF COWPEA (Vigna unguiculata L. Walp)

Cowpea (V. Unguiculata (L.) Walp) is consumed as human food and animal feed in many countries; in Mexico it is also used as green manure to improve soils. The study was conducted in La Paz, Baja California Sur, Mexico to determine if there is an intraspecific competition in V. Unguiculata and its effect on productive characteristics of the crop under field conditions. Three treatments consisting in placing 1, 2 and 3 seeds every 25cm in rows 15m long separated by 70cm, with 5 replicates, were compared. The following variables were evaluated: stem diameter, stem length, number of leaves, number of pods, forage weight and number of secondary stems. A multivariate analysis of variance was performed to explore the correlation between these variables. The performance of the studied variables decreased (P<0.001) as plant density of seeds increased. It is concluded that V. Unguiculata under field conditions presents infraspecffic competition with regard to the variables studied here.