Management of pearl millet downy mildew caused by sclerospora graminicola (Sacc.) Schroet

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Date
2015
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CCSHAU
Abstract
Downy mildew of pearl millet incited by Sclerospora graminicola (Sacc.) Schroet is the most widespread and destructive disease of pearl millet in India and other pearl millet growing area of the world. This disease is a major factor limiting full exploitation of high yield potential hybrids in India. In the present investigation biochemical characterization of pearl millet genotypes - HHB 223 and 7042 S was carried out at 30, 40, 50 and 70 DAS. Orthodihydroxy phenol and flavanol were higher in HHB 223 at early stages of growth and at later stages they started decreasing in HHB 223 but remained higher in comparison to susceptible. Total phenolic content was found to be higher in resistant genotype at 30 and 40 DAS but at 40 and 50 DAS it was higher in susceptible genotype but flavanol content decreased at later stages in susceptible genotype. Total chlorophyll and carotenoid content decreased with the progression of systemic infection in both resistant and susceptible genotypes. Total soluble sugars were higher in resistant genotype in comparison to susceptible genotype. Peroxidase and catalase activities were higher in susceptible genotype at early stages of growth but at later stages they were higher in resistant genotype. Polyphenol oxidase did not show any significant difference in resistant and susceptible genotype. Phenylalanine Ammonia Lyase activity was higher and continuously increased in susceptible genotype at all stages of growth whereas Tyrosine Ammonia Lyase activity was found in traces in both the genotypes. Protein content was initially higher in susceptible genotype at 30 DAS and 40 DAS but it decreased with disease progression. In field experiment, maximum germination and grain yield was observed on soil application of molybdenum whereas minimum disease incidence was recorded with molybdenum + copper + boron. Among different fungicides evaluated, minimum disease incidence was observed on seed treatment with metalaxyl 35 SD + spray of Ridomyl MZ 72% and seed treatment with metalaxyl 35 SD + spray of propiconazole. Among the different bioagents tested field emergence was maximum in treatment Bacillus pumulis (INR 7) + Chitosan and the disease incidence was minimum. Out of 209 entries of pearl millet screened against downy mildew, 25 were free from downy mildew, 124 showed < 10% downy mildew incidence, 57 ranged between 10-25% downy mildew incidence and only 3 entries exhibited more than 25% downy mildew incidence.
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Keywords
Diseases, genotypes, Sowing, Millets, Enzymes, Fungi, Planting, Biological phenomena, Phenols, Seed treatment
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