Development of a Low Volume Sprayer Nozzle for Ga3 Application: Enhancing Sustainability of F1 Hybrid Rice Seed Production in the Philippines

Abstract

In hybrid rice seed production, Gibberellic acid (GA3), a growth hormone, is normally applied to the mother rice plant (A-line) in order to facilitate panicle exertion and increase its chance to receive pollens from the father plant (R-line) thus enhancing seed setting. At present, the Filipino hybrid rice seed producers are using either the battery-operated ultra low volume (ULV) sprayer or the imported lever-operated knapsack (LOK) sprayer in the application of GA3. The former is being recommended by agricultural technicians however it is relatively expensive hence not all of the farmers are using it. The latter, which most of the farmers are using, requires a lot of water to use (300-500 l/ha) hence taking a lot of time and effort in carrying out the operation. This knapsack sprayer however can be a low-cost alternative for applying GA3 if only provided with a low volume (LV) nozzle. Unfortunately, no available sprayer nozzles could be found in the market that could satisfy the requirement. This study was conducted to develop a LV sprayer nozzle in order to provide Filipino hybrid rice seed producers a low cost but efficient alternative device for applying GA3. The developed LV nozzle was fabricated mostly out from plastic pipe fittings and other commercially available materials. It could be fitted easily on the lance of farmers’ sprayers. Field test results showed that the number of tank loads per hectare was reduced from 10-13 in the accompanying nozzle of a farmer’s LOK knapsack sprayer to 2-4 in the developed LV nozzle. This resulted to savings in time and cost of the GA3 application. Results of survey conducted after a pilot testing showed that all of the 21 farmer respondents preferred to use the developed nozzle over their existing nozzles.

Keywords: Gibberellic Acid, Hybrid Rice, Knapsack Sprayer, Low Volume Sprayer Nozzle, Rice Seed Production