Rainfed performance of different rice ecotypes applied with Paclobutrazol [manuscript]
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Date
2018
Authors
Meliza P. Magtalas
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Abstract
This study aimed to evaluate the effect of paclobutrazol (PBZ) in agronomic parameters of different rice ecotypes under rainfed condition, identify appropriate PBZ concentration for each ecotype, and identify combination of PBZ and rice ecotype with highest grain yield. The experiment was laid out in split-plot design with PBZ concentrations (0, 250, 500 ppm) as main plot applied at 14 days after transplanting while rice ecotypes (rainfed lowland-PSB Rc14; irrigated lowland-NSIC Rc222; upland special quality- Dinorado and lowland special quality- NSIC Rc216) as sub plot arranged in RCBD with three replications.
Water was drained 14 DAT and there was no standing water until harvest time. Peizometer reading at 14 DAT until harvest showed soil moisture at 44 - 66 cm below soil surface and soil moisture content at 18%.
Results showed that PBZ application at tillering stage has short term (21 days) effect of shorter plant height compared to untreated plant (0 PBZ), no effect in leaf chlorophyll content, and long term (14-49 DAT) effect in increasing tiller number which contributed to higher panicle number. PBZ also improved other yield components such as panicle length, number and percentage of filled grains, biomass and grain yield. PBZ concentrations and rice ecotypes for grain yield showed significant interaction incidcating appropriate PBZ concentration varies with rice ecotype. Lower PBZ concentration (250 ppm) gave highest grain yield for PSB Rc14 (4.50 t ha-1_ and NSIC Rc222 (7.75 t ha-1) while higher concentration (500 ppm) for Dinorado (5.76 t ha-1) and NSIC Rc216 (6.78 t ha-1). Over all, highest productivity under rainfed condition was obtained from NSIC Rc222 (7.75 t ha-1) with 250 ppm PBZ.