Deep sowing of dry direct-seeded rice: cultivar differences in seedling establishment and grain yield

Dry direct seeding of rice (DDSR) is being increasingly used in water-scarce areas across Asia. When drought occurs, deep sowing may enable germinating seeds to utilize the residual moisture below surface. Our objective was examine effects different depths on DDSR crop growth. Two yield experiments, one Philippines and other Japan, were established rainfed lowlands, but did not occur. Across at a depth 6 7 cm reduced percentage emergence compared with 1 2 (25% vs. 73%), which resulted lower (3.5 4.4 t ha−1). The relative (deep-sowing/shallow-sowing) positively correlated under sowing. Cultivars no significant reduction maintained high (>30%) Seedling’s ability emerge after greatly differed among cultivars: ranging from 0% 18% 8 10 cm, 11% 44% cm. An ancillary field experiment conducted during dry season Philippines: increased shallow (41% 5%), when soil surface severely dry. results suggest that choosing cultivars can tolerate prerequisite for using DDSR, future breeding should focus this tolerance.