Effect of Alectra Vogelii and Striga Gesnerioides Infestations on the Grain Mineral Elements' Concentration of Cowpea Varieties

Abstract

Effect ofAlectra VogeliiandStriga GesnerioidesInfestations on the Grain Mineral Elements' Concentration of Cowpea VarietiesField trials were conducted in 1999 and 2000 to investigate the effect ofStriga gesnerioidesandAlectra vogeliion the grain mineral elements' concentration of five cowpea varieties at harvest: IT82D-849, IT86D-534, IT89KD-245, KANO 1696 and SAMPEA7. The mineral elements analyzed were: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn) and zinc (Zn). Obtained data showed that the concentration of most elements was generally reduced in the grains of the cowpea varieties IT82D-849 and IT89KD-245 on bothAlectraandStrigainoculated plots. On the other hand, cowpea varieties KANO1696 and SAMPEA7 showed a tendency towards having increased concentration of about 50% of the element analyzed in each year on bothAlectraandStrigainoculated plots. In both KANO1696 and SAMPEA 7 there was a tendency towards the increase in the grain concentration of Mg and Zn and the decrease in K and Mn onAlectrainoculated plots and the increase in P and Mg but the decrease in Ca and Zn onStrigainoculated plots. The concentration of P in all the varieties in 1999 and 2000 (except IT89KD245 in 2000) was increased onStrigainoculated plots. Also, the concentration of Mg and N was increased in IT82D-849 on bothStrigaandAlectrainoculated plots in 2000. This study showed that,StrigaandAlectrainfestation generally reduced the mineral elements' concentration in the grains of cowpea varieties