不同生态区播期对直播稻生育期及温光利用的影响

【目的】探讨不同生态区直播条件下播期对不同类型水稻品种生育期及温光利用的影响，为品种及其适宜播期的科学区划布局提供初步理论依据。【方法】苏南太湖稻区常熟（N 31.4°）以迟熟中粳、早熟晚粳和中熟晚粳为材料，苏中里下河稻区姜堰（N 32.3°）以中熟中粳、迟熟中粳和早熟晚粳为材料，苏北淮北稻区东海（N 34.5°）以早熟中粳、中熟中粳和迟熟中粳为材料，通过分期播种试验，比较研究不同播期对直播稻生育期及温光利用的影响。【结果】随着播期的推迟，各类型品种的拔节期、抽穗期和成熟期相应推迟，生育期明显缩短，总体表现为播期每推迟1 d，生育期缩短0.6 d左右。同一品种类型，随纬度的升高，拔节期、抽穗期和成熟期逐渐延迟，生育期依次变长。同一试验点，随播期的推迟一般晚粳品种较中粳品种生育期天数缩短略多。生育期随播期推迟而缩短主要表现在营养生长期和营养生长与生殖生长并进期，变化范围为2-24 d，生殖生长阶段则相对稳定，变化范围仅为-2-1 d。各类型品种生育期积温和光照时数均表现出随播期的推迟呈显著或极显著的减少趋势，其差异主要源于抽穗前积温与光照时数的不同，其中尤以拔节前的差异最为明显，达到显著或极显著水平。同一试验点，各类型品种间生育期的积温与光照时数均表现为晚粳品种大于中粳品种；同一类型品种，随试验点纬度升高，积温呈依次减少的趋势，光照时数除杂交品种以外均呈依次增加的趋势。随播期的推迟，各类型品种的温光利用率均呈显著或极显著的下降趋势。播种至抽穗阶段和生育期的天数随积温的升高而线性增加，随日照时数的增加而线性减小；抽穗至成熟阶段的天数随积温的升高或日照时数的增加不同处理间表现不尽一致。【结论】播期对直播稻生育期及温光的利用有较大的影响。据此，对不同类型水稻品种直播适宜布局范围进行了初步区划，并综合分析后给出其能够安全成熟的可能播期，为大面积生产提供参考。

Effects of Sowing Date on Growth Stage and Utilization of Temperature and Illumination of Direct Seeding Rice in Different Ecological Regions

【Objective】 The objective of the study is to elucidate the effect of sowing date on growth stage and utilization of temperature and illumination of direct seeding rice of different varieties in different ecological regions,and to provide a preliminary theoretical basis for the scientific division and distribution of different varieties and its possible sowing date.【Method】Taking late-maturing medium japonica rice,early-maturing late japonica rice and medium-maturing late japonica rice in Taihu rice-growing district in Changshu(Sunan,N31.4°),medium-maturing medium japonica rice,late-maturing medium japonica rice and early-maturing late japonica rice in Lixiahe rice-growing district in Jiangyan(Suzhong,N 32.3°),early-maturing medium japonica rice,medium-maturing medium japonica rice and late-maturing medium japonica rice in Huaibei rice-growing district in Donghai(Subei,N 34.5°) as experimental materials,the effect of sowing date on growth stage and utilization of temperature and illumination of direct seeding rice was comparatively Studied.【Result】The results showed that along with the delayed sowing date,the date of jointing,heading and maturity of all varieties were correspondingly delayed,growth stages significantly reduced that the growth stages reduced by 0.6 days when the sowing date delayed one day.For the same type varieties,the date of jointing,heading and maturity gradually delayed and the growth stages gradually increased with latitude increasing.In the same site,the number of days of growth stages of late japonica rice reduced slightly more than the medium japonica rice with the delayed sowing date.Growth stages reduced with the delayed sowing date because of the vegetative growth period and the vegetative and reproductive growth period reduced which in a range of 2 to 24 days,the reproductive growth period was relatively stable which in a range of-2 to 1 days.The accumulated temperature and illumination hours at growth stages of all varieties reduced significantly or very significantly,which because of the accumulated temperature and illumination hours before heading,especially before jointing,the difference was significant or very significant.In the same site,the accumulated temperature and illumination hours at growth stages of late japonica rice were more than the medium japonica rice.For the same type varieties,with latitude increased,the accumulated temperature reduced,illumination hours reduced except for japonica hybrid rice.The utilization of temperature and illumination of all varieties reduced significantly or very significantly with the delayed sowing date.The number of days from sowing to heading and growth stages increased linearly with the increase of the accumulated temperature and decreased linearly with the increase of illumination hours.The number of days from heading to maturity was different between different treatments with the increase of the accumulated temperature or illumination hours.【Conclusion】 Sowing date had great effects on growth stage and utilization of temperature and illumination of direct seeding rice.Accordingly,a preliminary division for the direct seeding rice of different variety types was made for providing a reference for the production in the large area.