Abstract: Based on the late rice variety Yanfeng 47 as the research object, the experiment of sowing by stages was carried out in Panjin city in 2015. The effects of different sowing date and greenhouse seedling microenvironment on seedling quality of single season japonica rice were analyzed. The results showed that with the delay of sowing date, the growth period of japonica rice seedlings was shortened and the growth process was accelerated, which was mainly embodied in sowing-seedling stage and emergence-1.5 leaf age. The growth rate of japonica rice seedlings was significantly negatively correlated with accumulated temperature and sunshine time, and was not significantly correlated with daily mean temperature and daily average relative humidity. The different sowing date had little influence on the final plant height of japonica rice seedlings. At 1.5-leaf-age to 2.5-leaf stage, japonica rice seedlings mainly developed root system, but it mainly concentrated on the accumulation of dry matter in the ground at 2.5-leaf to 3.5-leaf-age period, and the root system of the seedling with late sowing date was strong. There were no significant correlations between rice seedling height, dry matter, root-shoot ratio, daily average temperature, accumulative temperature, sunshine time and daily mean relative humidity. Combining with local production practice, the suitable sowing date of late maturing japonica rice was determined around April 18.

Key words: the single season japonica rice, seedling by stages, micrometeorology, seedling quality