Ecophysiological responses of peanut (Arachis hypogea) to shading due to maize (Zea mays) in intercropping systems
The purpose of this study is to evaluate, in an experimental station, the quantitative impact of shading on the productivity of peanuts, by intercropping with three varieties of maize. Sufficient water and fertilizers were provided and several levels of shading were induced. During the 2003 growing season, shading was induced with three sowing densities of maize DMR-ESRW, a planophile variety of maize. During the 2004 growing season, three intercropping varieties, TZEEW, DMR-ESRW and Obatanpa, were evaluated for shading of the peanut canopy. The main data collected were etiolation, dry matter productivity and seeds yield. \'Gynophore index\', which integrates both growth and seed yield aspects, was also measured. Results showed significant differences for measured parameters, in correlation with light reduction. According to the density and the variety of the maize intercropped, residual light above the peanut canopy, varied from 72 % to 53 %. The length of main axis varied from 51.4 cm for control plot of peanut alone to 63.9 cm for peanut intercropped, with maize variety DMR-ESRW. Etiolation contributes to reduce the number of pods. The impact of this reduction was estimated with gynophore index; highly correlated with number of pods. Dry matter and seed yield dropped respectively by 35 % under TZEEW and 55% under DMR-ESRW. The relationship between the yield reduction and the extent of shading reflected the steps of adaptation of groundnut to the lack of light stress.
Keywords: Peanut, Maize, Intercropping, Etiolation, Gynophore index.
Cameroon Journal of Experimental Biology Vol. 4 (1) 2008: pp. 29-38