Evaluating Wheat Pre-Harvest Sprouting Risk Using Indicator Based on Meteorological Data From 1981 to 2020 in China

Abstract

The occurrence of wheat pre-harvest sprouting (PHS) has been intensified with global climatic change and increasing rainfall from 1981 to 2020, which has led to a drastic reduction in wheat quality and yield. Therefore, scientific assessments of the potential climatic risk of wheat PHS in different areas based on historical meteorological data help identify the high-risk areas, select suitable wheat cultivars and optimise cultivation measures for wheat production. However, to date, risk assessment criteria have not been established for evaluating the potential climatic risks associated with wheat PHS in different areas. This study analysed temperature and relative humidity change trends and identified the boundary line between the Yellow and Huai River Valley Facultative Wheat Zone and the Middle and Lower Yangtze River Valley Winter Wheat Zone using climatically similar points. The experimental material comprised the wheat PHS-sensitive variety Xiaoyan 22. Wheat PHS risk assessment criteria were proposed based on the whole ear germination test and daily temperature and relative humidity data collected during the wheat harvest period from 1981 to 2020 in the two wheat regions. The climatic risk associated with wheat PHS was graded for these two areas. Our results showed that from 1981 to 2020, the temperature increased by 0.38°C/10 years and 0.26°C/10 years, while the relative humidity decreased by 1.8%/10 years and 0.39%/10 years during the wheat harvest period in the two wheat regions. Further analysis of the factors influencing the climate boundary between the Yellow and Huai River Valley Facultative Wheat Zone and the Middle and Lower Yangtze River Valley Winter Wheat Zone revealed that, from 1986 to 2020, the eastern section of the climate boundary exhibited significant southward or northward migration trends in Anhui and Jiangsu Provinces. The central section of the similar climate boundary in Henan and Hubei Provinces also showed a southward trend but a relatively small range, whereas the western section fluctuated up and down the original dividing line, with a northward migration trend in Gansu Province. A new risk assessment indicator, P, was proposed in this study based on meteorological data from 1981 to 2020 in China. During this period, the wheat PHS risk increased from north to south and west to east in the Yellow and Huai River Valley Facultative Wheat Zone and from north to south in the Middle and Lower Yangtze River Valley Winter Wheat Zone. Furthermore, the overall wheat PHS climate risk in the Yellow and Huai River Valley Facultative Wheat Zone was lower than that in the Middle and Lower Yangtze River Valley Winter Wheat Zone. Risk assessments of wheat PHS distribution and damage will provide a scientific basis for the accurate distribution of pre-harvest sprouting-resistant wheat varieties and improve the resistance to natural disasters and the safety of wheat production.