High temperature inhibits germination of jalapeno and cayenne pepper

The germination of five commercial cultivars of jalapeno and cayenne pepper were tested to determine cultivar response of Capsicum annuum L. to supra- optimal temperatures. Two seedlots of 'Cayenne, Large Red Thick', 'Ole', 'J alapeno M', 'Mitla', and 'Tam Veracruz' were evaluated on a thermogradient table at temperatures of 20,25, 30, 35, and 40 degreesC. Percent germinatio n and time to 50% of final germination (T-50) were calculated. All cultivar s exhibited thermodormancy, but the degree of inhibition varied within temp erature and cultivar. No cultivar had >1.0% germination at 40 degreesC. Gen erally, the T-50 varied among cultivars, but not among temperatures within a cultivar (T-50 at 40 degreesC was not measured). Cultivar selection shoul d be considered when growing fall transplants in Florida.