Nitrogen fertilization and head rot in broccoli

Abstract

An increase in the amount of N supplied (from 0 to 196 kg N/ha) to broccoli (Brassica oleracea var. italica) cv. Emperor led to an increased incidence of head rot (probably caused by a number of Pseudomonas and Erwinia species), which resulted in a decrease of the amount of marketable produce. Indications were found that head weight and head DM content are, probably indirectly, involved in limiting head rot at low N levels. The harvest index was not influenced by N treatment. Identification of the mechanisms which resulted in limited head rot at low N levels, could help to identify breeding characteristics for screening in agronomic evaluation programmes for broccoli cultivars under normal N levels.