Black point of wheat: in vitro production of symptoms, enzymes involved, and association with Alternaria alternata

Abstract

Black point in wheat has commonly been thought to be caused by Alternaria alternata. To obtain a method for screening for resistance to this problem, the process by which A. alternata infects wheat grain was observed in resistant and susceptible varieties. No association was found between infection with A. alternata and black point symptoms. A technique was developed to produce symptoms in vitro which showed the detection and location of the peroxidase enzymes involved. Isoelectric focusing (IEF) determined considerable differences in peroxidase isoenzyme activity from black point resistant and susceptible wheat varieties. The potential exists for using IEF as a tool for rapid screening for black point resistance.