RESPONSE OF 21 SPRING WHEAT-CULTIVARS TO FORMALIN SEED TREATMENT

Formalin has long been used as a seed treatment. Very little informati on, however, is available regarding the genotypic response of wheat to this chemical. The response of genetically diverse spring wheal (Trit icum aestivum L.) cultivars to formalin seed treatment was evaluated i n field and laboratory experiments. Under controlled conditions formal in reduced the rate and degree of seed germination, and rate of water uptake. Germination was reduced by between 8 and 14% over exposure per iods ranging from 4 to 72 hours. Germination was reduced by 7, 41, and 90%, respectively, after treatment with the recommended concentration (1X), twice the recommended concentration (2X) and four times the rec ommended formalin concentration (4X). Rate of germination was reduced by 45 and 58% after treatment with the 1X and 2X formalin concentratio ns, respectively. The effect of formalin seed treatment on seedling es tablishment, shoot dry weight, and grain yield of the 21 wheat cultiva rs was assessed under field conditions in 1994 and 1995. Seedling esta blishment and shoot dry weight were affected by seed treatment in both years. There was a significant cultivar by formalin concentration int eraction for all laboratory measurements and seedling emergence under field conditions. The nature of this interaction was such that no cons istent pattern of cultivar difference in response to formalin could be determined.