Abstract: 10 varieties including sterile lines, indica rice and japonica rice, were chosen as experimental materials.The daily and hourly flowering percentage of single panicle,first flowering panicles in each day and total flower amount were measured.The theoretical flowering percentage was modeled by using the normal distribution function,and the stepwise regression was established to calculate the departure of flowering percentage considering the effect of temperature, humidity, precipitation and sunshine duration. Then the diurnal variation of the population flowering habit could be simulated by the daily and hourly flowering percentage, first flowering panicles in each day and total flower amount. The results showed that rice flowering habit was mainly decided by the genetic characteristics of varieties. Japonica rice had an obvious peak of flowering percentage during 11:48am-12:22pm and a longer flowering period for 7.7d. While the flowering peak of indica rice was earlier than that of japonica rice (9:36am-10:53am) and they had a shorter flowering period for 6.0d. The sterile lines had not obvious peak of flowering percentage and its flowering period was 7.0d between japonica rice and indica rice. Moreover, the meteorological factors would change the rule of rice flowering mentioned above, which led to the ralative departure of daily and hourly flowering percentage in-16.85% to 28.78% and -66.88% to 95.03%, respectively. Especially for indica rice and sterile lines,the departure was sensitive to the meteorological factors, which was showed in the correlation coefficient P<0.05 and P<0.01.Therefore, with considering the meteorological factors,the precision of flowering amount for a single panicle would be improved, which was also better to estimate the population flowering amount. It was positive to master the biological characteristics of rice flowering, understand the effect of meteorological conditions on rice flowering habit, which could provide a basis reference to understand rice hybrid breeding and male sterile line.

Key words:  Rice population, Japonica rice, Indica rice, Flowering period, Flowering time, Flowering amount