Abstract

GARCIA-MATEOS, Ma. del Rosario; SANCHEZ-NAVARRO, Claudia; MARTINEZ-SOLIS, Juan  and  PEREZ-GRAJALES, Mario. Phytotoxic activity of manzano hot pepper (Capsicum pubescens R & P) extracts. Rev. Chapingo Ser.Hortic [online]. 2013, vol.19, n.4, pp.23-33. ISSN 2007-4034.

The search for new natural herbicides was performed using studies of phytotoxic substances because they do not affect the environment and are less toxic than synthetics. In literature there is little evidence of phytotoxic effects of capsaicinoids, present in the genus Capsicum, thus the objective of this research was to evaluate in vitro the phytotoxic effects of the extracts of the manzano hot pepper (Capsicum pubescens R & P) fruit on germination and vigor of Amaranthus hybridus L., Lactuca sativa L., Ipomoea purpurea L. and Bidens odorata Cav. A germination test was performed according to the methodology of the International Seed Testing Association. The effect of six concentrations of extracts (0.5, 1.5, 2.5, 5.0, 10, 20 % v/v), capsaicin (0.1 w/v) and ABA (0.01 w/v) was evaluated in an experiment using a completely random design with four replications of 50 seeds each. The control was distilled water. The variables evaluated were: number of germinated seeds (NGS) and vigor (length of radicle, RL, length of the aerial part, LAP). Variance analysis and Tukey comparisons (P ≤ 0.05) were performed. The dichloromethane extract, compared to the ether extract, caused the most phytotoxic effect on the germination of A. hybridus and L. sativa, in which the percentage dropped to 100 %; it also negatively affected the vigor of I. purpurea. The phytotoxic effect of capsaicin on germination and vigor was only evident in A. hybridus.

Keywords : Capsaicin; extracts; phytotoxicity; germination; vigor.