Allelopathic effect of Jatropha curcas (Lin) leachate on germination and early seedling growth of five (5) agricultural crops in Kano, Nigeria

Abstract

Allelopathy refers to the chemical inhibition of one species by another. Decline in crop yields in cropping and agroforestry system in recent years has been attributed to allelopathy effects.Laboratory studies were  conducted at Research Centre for Tissue Culture, Kazaure, Jigawa state (Longitude08¢ª 41 . N and Latitude12^o 65 . E). The aim of this study is to investigate the allelopathic potentials of aqueous leaf extract of Jatropha curcason seed germination and early seedling growth of five (5) crops. J. curcas aqueous leaf extract was prepared by 100g, 50g, 20g powder  dissolved in 500ml double distilled water and were tested for their  allelopathic effect on some growth parameters of maize, millet, guinea  corn, cowpea and ground nut. The effect of the different concentrations was compared with that of distilled water (control). Healthy seeds were sought and surface sterilized with 1% sodium hypochloride for 20 minutes.  Laboratory study was conducted using sterilized petri dishes with double layer of Whatman filter paper at averagely 27^oC and 70% humidity. An interval of 24, 48, 76 and 92 hours were recorded on germination studies
while radicle and shoot lengths at 92nhours respectively. Decreased in germination percentage, shoot and radicle lengths of the crops studied were observed to be concentration dependent.All the concentration of the different extracts had inhibitory effect on the germination of all the crops
compared to control. Phytochemical screening of the J. curcas leaf extract was also determined.

Keywords: Allelopathy, Jatropha, Germination, Phytochemicals, Extract.