Effects of temperature, light regime and substrates on the production and germination of Stenocarpella maydis pycnidiospores

Abstract

This study aimed to evaluate the production and germination of Stenocarpella maydis pycnidiospores under in vitro conditions as affected by substrate composition (sorghum, wheat, black oat or barley), light regime (continuous dark, 12-h light dark(-1) or continuous light conditions), and incubation temperature (21, 24, 27, 30 or 33 degrees C). Each substrate (20 g of grain) was soaked in 100 mL of water for 24h and sterilized twice for 20 min at 127 degrees C. Three plugs (5 mm diameter) of a single-spored culture of S. maydis were used as inocula for each substrate. Assessments of pycnidiospore production per gram of grain and percent germination were made 14 days after inoculation. Barley, black oat or wheat grains were the best substrates for the mass production of S. maydis pycnidiospores and the maintenance of high germination rates. The highest pycnidiospore production (67,600 pycnidiospores g(-1)) was obtained using barley grain as a substrate with incubation at 27 degrees C under a 12-h light dark(-1) cycle.