Long-Term Dynamic of Cold Stress during Heading and Flowering Stage and Its Effects on Rice Growth in China

Zhenwang Li,Changwen Du,Haixiao Ge,Zhengchao Qiu

doi:10.3390/atmos13010103

Abstract

Short episodes of low-temperature stress during reproductive stages can cause significant crop yield losses, but our understanding of the dynamics of extreme cold events and their impact on rice growth and yield in the past and present climate remains limited. In this study, by analyzing historical climate, phenology and yield component data, the spatial and temporal variability of cold stress during the rice heading and flowering stages and its impact on rice growth and yield in China was characterized. The results showed that cold stress was unevenly distributed throughout the study region, with the most severe events observed in the Yunnan Plateau with altitudes higher than 1800 m. With the increasing temperature, a significant decreasing trend in cold stress was observed across most of the three ecoregions after the 1970s. However, the phenological-shift effects with the prolonged growing period during the heading and flowering stages have slowed down the cold stress decreasing trend and led to an underestimation of the magnitude of cold stress events. Meanwhile, cold stress during heading and flowering will still be a potential threat to rice production. The cold stress-induced yield loss is related to both the intensification of extreme cold stress and the contribution of related components to yield in the three regions.

Highlights

Extreme climate events have brought considerable uncertainty to the quantity and quality of crop yields, and as such are broadly recognized as a serious threat to agricultural production [1,2,3,4]
In Northeastern Plain (NEP), Yunnan Plateau (YNP) and SMLYR, the regression coefficients of the selected best linear functions of ∆yield with ∆cold degree days (CDD) were −0.042, −0.053 and −0.016, respectively, which means that, with each one degree per day increase in ∆CDD during heading and flowering, the yield decreased by 42 kg/ha, 53 kg/ha and 16 kg/ha in the three ecoregions, respectively
Using a long-term, site-specific climate- and yield-variable dataset across three rice cultivation regions of China that are frequently hit by cold stress, the spatiotemporal trends of cold stress during the heading and flowering stages of rice were investigated in this study, and the impacts on growth and yield analyzed

Summary

Introduction

Extreme climate events have brought considerable uncertainty to the quantity and quality of crop yields, and as such are broadly recognized as a serious threat to agricultural production [1,2,3,4]. Cold stress can damage rice plants during any developmental stage from germination to maturity [13,14,15], with the reproductive phases, especially heading and flowering, being susceptible [9,16]. Low temperature during these stages may lower the physiological metabolism and growth and development of rice, induce flower abscission, pollen sterility, pollen tube distortion, ovule abortion and reduce the fruit set process, which cause yield reduction [9,14,17]. As shown in a field experiment by [18], exposure to low temperature in the flowering stage can result in rice spikelet sterility at a rate as high as 89.7%, and, compared to tolerant genotypes, it can reduce the fertilization efficiency and quantity of pollen grains on stigma in lowtemperature-susceptible genotypes by 97% and 76%, respectively

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Discussion

Conclusion