EFFECTS OF FUSARIUM HEAD BLIGHT AND SEED TREATMENT ON GERMINATION, EMERGENCE, AND SEEDLING VIGOR OF SPRING

In 1993, following the worst fusarium head blight epidemic on record i n southern Manitoba, two seed lots of each of the hard red spring (HRS ) wheat cvs. Glenlea, Katepwa, and Roblin, the durum cv. Sceptre, and the Canada Prairie Spring (CPS) cv. AC Taber were tested for germinati on, emergence, dry weights of shoot and root, and response to seed cle aning and fungicide seed treatment. Seed treatment fungicides included DB-Green L, Dithane M-45, NM Drill Box, Vitaflo 280, and Vitavax S. S ound seed from 1992 and both cleaned and uncleaned seed from 1993 were used as controls. Fusarium graminearum was the predominant species is olated from the 1993 seed. Seed of Sceptre durum was of very poor qual ity; cleaning did not improve grade and fungicide treatment had minima l effect on germination or emergence. Cleaning reduced tombstone level s in Katepwa, Glenlea, and Roblin, and improved the grade of the latte r two cultivars. Fungicide treatments generally improved germination a nd emergence but efficacy was dependant on temperature at germination and cultivar. Dry shoot weight in Glenlea was significantly lower than in controls after treatment with DB-Green L and Dithane M-45; no othe r significant differences in dry shoot weight were recorded. Dry root weight of plants from 1993 seed, treated and untreated, was significan tly less than that of 1999 control seed, and seed treatment did not af fect root weight.