DOUBLE HARVESTS: HIGHER HYBRID RICE PRODUCTION IN RAINFED ECOSYSTEMS THROUGH RATOONING

摘要

For the past decades; rice ratooning studies have been conducted under irrigated conditions. To help cope with the increasing demand for food; the thrust of this study is to develop or improve technology with emphasis on increasing hybrid rice production through ratooning (double harvesting) under rain fed ecosystems. The very high cost of hybrid seeds is a major constraint faced by farmers who wish to engage in hybrid rice production. Since ratooning is known to reduce costs; at PhilRice Batac we compared two hybrid rices (Mestizo and Magilas) and two inbred rices (PSB Rcl2; PSB Rcl4) at three cutting heights (5; 10 & 20 cm) following the conventional method of ratooning. The ratoon crops were harvested 72 days after the main crop. Results showed that Magilas outyielded the other varieties at all cutting heights; yielding 4.3 tons /ha; this was 51% of the main crop yield; which was 8.4 tons/ha. This relatively high yield was found associated with higher ratoon rigor and ratoon survival. With a double harvest (main crop and ratoon); the total yield of Magilas was 12.7 tons/ha in 173 days from transplanting of main crop; accompanied with much reduced inputs in the ratoon. In comparison; the Mestizo ratoon crop yielded 2.4 tons/ha less than Magilas.The results emphasize the importance of the ratooning ability of the variety/parent. The net income for the ratoon crop ivas P30;564/ha while that of farmer's practice (main crop; transplanted rice) was P503/ha. The results indicate that with the rightvariety and proper ivater conservation technique; ratooning technology could be successfid in a rain fed ecosystem.