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

Nianbing Zhou,Hongcheng Zhang,Qiang Shi,Haiyan Wei

doi:10.3390/agriculture11070618

Abstract

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.

Highlights

The rice planting area along the lower reaches of Huai River accounts for about 45% of the rice planting area in Jiangsu Province [1]
Previous studies can typically be divided into two categories: the first is to use an artificial climate chamber or incubator with different temperatures and light environments during a key growth stage of rice to study how temperature and light influence the formation of rice yield or quality [12]; the second is to study the influence of single factor of temperature or light on rice yield and quality through open active warming or shading, which has little influence on other environmental factors on farmland [13,14]
We studied the response of rice eating quality to environmental factors

Summary

Introduction

The rice planting area along the lower reaches of Huai River accounts for about 45% of the rice planting area in Jiangsu Province [1]. Since 1960, the yield per unit area of rice in this region has significantly increased [2], primarily due to improvements in rice varieties and innovative cultivation techniques [3,4,5,6]. Much research has been performed on the effects of temperature and solar radiation (T and R) on rice production. It is difficult to study the effects of temperature and light on rice yield and quality for several reasons. Seven different environmental treatments were used to grow rice to study the effects of temperature and light on the yield and quality of high-quality rice, which represent the actual field growth conditions of rice. Solar radiation affects rice quality during the grain-filling period. The ability of the plant to synthesize carbohydrates weakens and the number of carbohydrates transferred to the grain decreases, while the amount of N and protein transferred to the grain per unit increases [27]

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Discussion

Conclusion