2015年在四川省德阳市进行大田水稻直播试验，以早稻、早熟中稻、中熟中稻、迟熟中稻等4种类型水稻品种为材料，设置3个播期茬口（前茬作物分别为蔬菜、油菜和小麦），研究不同茬口和品种类型对直播稻产量形成的影响，为茬口及品种类型的科学搭配提供依据。结果表明，随着播期的推迟，水稻播种至齐穗、齐穗至成熟的生育期缩短；早稻、早熟中稻、中熟中稻的产量先增加后下降，迟熟中稻的产量显著降低。蔬菜茬口和油菜茬口以中熟中稻的产量最高，分别为8.47 t/hm2和9.30 t/hm2，小麦茬口则以早熟中稻的产量最高，为7.99 t/hm2。随着播期的推迟，早熟中稻、中熟中稻的干物质积累量呈先增加后降低的趋势，而早稻、迟熟中稻的干物质积累量呈降低趋势。由此可见，成都平原蔬菜茬口和油菜茬口水稻直播以选用中熟中稻品种较为适宜，小麦茬口水稻直播则选用早熟中稻较好。

The present study was conducted to investigate the effects of crop rotation systems and variety type on yield formation under direct seeding rice. The result will provide a theoretical basis for scientific adoption of suitable variety types under direct seeding for different crop rotation systems in Deyang City, Sichuan Province. A field experiment with early rice （ER）, early-maturing mid-season hybrid rice （EM）, medium-maturing mid-season hybrid rice （MM）and late-maturing mid-season hybrid rice （LM） were conducted to clarify the characteristics of yield formation and biomass production of variety types under direct seeding condition and cropping rotation systems. The results showed that, with the delay of sowing date, the growth duration from sowing to heading and heading to maturity were shorten, the grain yield of ER, EM and MM increased first and then decreased, and the grain yield of LM decreased significantly. MM produced the highest grain yield with 8.47 t/hm2 and 9.30 t/hm2 in green vegetable-rice cropping system and rape-rice cropping system, respectively; while EM get the highest grain yield in wheat-rice cropping system, which reached 7.99 t/hm2. With the delay of sowing date, the biomass of EM and MM increased first and then decreased, while the biomass of ER and LM decreased significantly. It is suggested that high grain yield could be achieved by adopting medium-maturing mid-season hybrid rice under direct seeding condition in green vegetable-rice and rape-rice cropping system, and early-maturing mid-season hybrid rice was suitable for wheat-rice cropping system under direct seeding condition.