Effects of Main Meteorological Indicators on Eating Quality of Rice in Lower Reaches of the Huai River

The main meteorological indicators affecting the eating quality of rice (Oryza sativa L.) in the lower reaches of Huai river were studied and the optimal sowing time range for obtaining good eating quality was put forward. Compared with solar radiation, rainfall, and humidity, temperature is the primary meteorological factor affecting the eating quality of rice in the lower reaches of the Huai river. Sowing the rice on different dates altered the heading and maturity dates of rice, and the difference between the mean daily temperature (Tmean) from the heading to maturity stage reached 4.6–5.0 °C. The Tmean from heading to maturity for all treatments was less than 23.5 °C. When the temperature was lower than 20.2 °C during the grain filling period, the value of the comprehensive evaluation of eating quality (CEQ) of the three types of rice decreased significantly. The medium-maturing japonica soft rice varieties (SMR), late-maturing japonica soft rice varieties (SLR), and late-maturing japonica non-soft rice varieties (LR) varieties that were subjected to low temperatures had a higher amylose content and protein content. Overall, the eating quality of rice in the lower reaches of the Huai river was affected by the low Tmean after the heading stage. The mean daily temperature (Tmean) range from the heading to maturity stages of SMR, SLR, and LR varieties that produced relatively high CEQ were 20.2–23.3 °C, 20.2–22.1 °C, and 20.3–22.1 °C, respectively. The optimal sowing date ranges of SMR, SLR, and LR were 16 May to 1 June, 16 to 18 May, and 16 to 20 May, respectively