Seed storage with PGPR for seedling vigor and downy mildew reduction of sweet corn
2007
Kasem, S. | Prathuangwong, S., Kasetsart Univ., Bangkok (Thailand). Dept. of Plant Pathology
Research was initiated on seedling vigor and induced systematic resistance against downy mildew infection using plant promoting rhizobacteria (PGPR)strain Bacillus amyloliquefaciens KP546 to coat and store seeds of sweet corn (Zea mays) cv. Insee 2. Seeds were surface sterilized with 10% Clorox and dripped in KPS46 suspension (10sup5 cfu/ml and 20 ml/1 kg seeds) for 15 min and dried overnight at room temperature. The KPS46 seed coating was compared with those seeds treated with chemical (metalaxyl), KP546 + metalaxyl and conventionalism (metalaxyl + carbendazim). After these were preserved at 10 or 28 deg C (room temperature), seed germination and seedling vigor (root length and shoot height)were determined every 30 days using blotter techniques under laboratory investigation. At 150 days storage, these were also tested for enhanced resistance against downy mildew which the coated seeds were sown in mini plot(3x3 m plot size and 3 replications with RCBD design )and the 7-day old seedling were in oculated with pathogenic Perenosclerospora sorghi(10sup6 spores/ml)using a backpack sprayer under field conditions.In room temperature and 10 deg C stored for 90 days, treatment KP546 + and metalaxyl exhibited highest efficacy in seed germination , seedling vigor and fresh weigh, but 10% seed germination decreased in both treatments stored at room temperature was found at 120-day incubation. However,these two treatments stored at 10 deg C were observed that all parameters were still highest measurement with over 90% seed germinations at either 120- and 150-day preservation. When 150-day storage seeds at 10 deg C were sown and inoculated with, downy mildew pathogen at National Corn and Sorghum Research Center, Nakhon Ratchasima, the induction of plant resistance was achieved by coating seeds with KP546 + metalaxyl resulted 72% reduction of downy mildew incidence over the nontreated control, followed by metalaxyl, KP546 and conventional coating, respectively. A present study indicates that temperature influences storage time and ability of PGPR strain in enhanced seed quality.The PGPR strain KP546 combined metalaxyl have the ability to increase reliable seed germination,seedling vigor and plant resistance against disease which were more consistent than the individual coated seeds done after a long storage time.
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