Objective This study aims to compare the effects of ratoon and direct seeding cultivation methods on rice yield, and identify high-performing ratoon rice and direct-seeded rice varieties. It will provide important references for variety selection of late-season ratoon rice and direct-seeded rice in South China, and offer theoretical support for regional variety optimization and the application of simplified cultivation techniques.

Method Field experiments were conducted in Guangzhou using 15 conventional rice varieties for ratoon cultivation and 15 varieties (seven conventional and eight hybrid) for direct seeding. In the ratoon experiment, the main crop was manually harvested at maturity, leaving a 15 cm stubble, and the ratoon crop was allowed to regrow naturally. Yields of both the main and ratoon crops were measured based on 18 plants, and growth durations were recorded. In the direct-seeding experiment, both transplanting and direct-seeding methods were applied to assess seedling establishment rate, heading date, maturity period, plant height, and yield performance.

Result All 15 ratoon varieties exhibited lower yields than their main crops, with an average reduction of 33.69%. 'Hefuzhan' achieved the highest ratoon yield (393.00 g) and annual total yield (877.58 g), followed by 'Yueyitang 1. Henongsimiao' 'Hefuzhan' and 'Yueyitang 1' also had the longest ratoon growth duration (80 days). In the direct-seeding trial, 'Yuenuo 2' recorded the highest seedling establishment rate (77.34%). 'Tailiangyou 1' 'Yuehesimiao', and 'Hefuzhan' exhibited the longest growth duration (111 days) under direct seeding, while 'Yuenuo 2' 'Yuefujinzhan' and 'Huanghuazhan' matured 6-7 days earlier than their transplanted counterparts. The highest yield under direct seeding was obtained by 'Wolianyouyueyasimiao' (646.17 g).

Conclusion Based on ratoon yield and total productivity, 'Hefuzhan' and 'Yueyitang 1' are recommended as promising ratoon rice varieties for Guangdong and the broader South China region. Considering seedling establishment and yield performance, 'Yuenuo 2' 'Yuefujinzhan' and 'Huanghuazhan' are identified as representative varieties suitable for direct-seeding cultivation.