Ability of vitamins to induce downy mildew disease resistance and growth promotion in pearl millet

The use of biotic and abiotic inducers for the development of host resistance is a sustainable approach for plant disease management. In the present study, vitamins, pyridoxine, folic acid, riboflavin, niacin, D-biotin and menadione sodium bisulphite (MSB) were used to treat pearl millet seeds to test their ability to induce resistance to downy mildew disease caused by Sclerospora graminicola. A 6 h seed-soak treatment with vitamins at 20 mM enhanced germination and seedling vigour significantly and also induced downy mildew disease resistance. Among them, MSB treatments offered 73% protection while niacin and riboflavin gave 63% and 62% protection, respectively. The vitamins offering promising protection were used in combination to treat the seeds, but no synergistic action was evident with either combination treatment. Vitamin seed treatment and foliar spray application showed similar results when applied individually. However, seed treatment followed by a foliar spray with a combination treatment of MSB and niacin at 7 d after seedling emergence offered higher protection (74%) against downy mildew disease. Seeds treated with vitamins induced maximum resistance in the seedlings by the fourth day after pathogen inoculation and the resistance persisted till the end of the growth period of the crop. The vitamin treatments had a growth promotional effect and significantly increased the yield compared with the untreated control. Possibilities for controlling downy mildew disease of pearl millet with vitamins are discussed. (c) 2007 Elsevier Ltd. All rights reserved.