Objective   Effects of seed sowing time and ambient temperature at grain-filling on the agronomic traits and rice quality/flavonoid content of Ziliangyou 737 were analyzed for improved the cultivation.

  Method   Seeds of Ziliangyou 737 were sowed at intervals to vary the growing period and harvest season for studying the effects of sowing time and atmosphere temperature at grain-filling stage on the agronomic traits of the plants and quality and flavonoid content of the rice. In 7, 10, 14, and 21 d after start of grain-filling as well as at grain maturity, data were collected for a statistical analysis on the rice crops sowed on various dates.

  Result   Under a shorter growing season, the plant height declined; the spike length became longer, then shorter; the seed setting rate and yield reduced, then increased; and the effective accumulated temperature (EAT) decreased gradually. The ∑H (High temperature hours) and ∑Th (Thermal accumulated temperature hour) within 10 d after grain-filling significantly affected the seeding rate of the mature seeds, so did the TA (Average temperature) within 14 d after grain-filling. When TA was 31.645 ℃, the seeding rate reached the lowest level, but the effect was lessened with increasing ambient temperature as the grain matured. High ∑Td (Daily thermal accumulated temperature) at 21 d after initial filling resulted in higher rate of failed grain-filling which translated to a lower seeding rate. VB₅, VB₆, and VB₂ were the vitamins in the greatest amounts found in the grains, but no significant correlation was found between vitamin contents and sowing time. Late sowing caused linear decline in grain amylose due to decreased ∑H, ∑Td, and ∑Th. High temperature affected the amylose content positively, but the effect was less at the late filling stage. Controlling TA at a level below 26.84 ℃ could help maintain the quality of the waxy rice crop sowed in late season in Fujian. The contents of anthocyanins and flavonoids correlated to the sowing time as shown by the color of seed hull that changed from reddish brown to dark black. From 14 d after grain-filling till maturity, ∑Td, TA, and EAT became extremely significant factors in the color change as a rising temperature mitigated anthocyanins and flavonoids.

  Conclusion  Scheduling of Ziliangyou 737 sowing significantly affected the growth and grain quality of the waxy rice. By controlling a TA less than 26.84 ℃ and an EAT at 2336.69–2390℃·d during grain-filling, crop yield and rice quality could be maximized. In Fujian, sowing between June 15 and 25 would thus be desirable. For other localities, cultivation in areas at high altitude or those that provide low TA at grain-filling stage would be recommended for Ziliangyou 737.