Abstract: Based on the phenological observation data of winter wheat and meteorological data (temperature, precipitation, and sunshine durations) in Nyingchi from 1991 to 2020, we identified the leading meteorological factors influencing the key development stages of winter wheat in southeastern Tibet, following the analysis of the variation in phenology in the context of global warming by statistical methods such as linear propensity estimation method, Pettitt method, correlation analysis and dominance analysis method. The heat resources of vegetative growth period (VGP), reproductive growth period (RGP) and whole growth period (WGP), including average, maximum, and minimum temperature, exhibited increasing trends in the southeast Tibet in recent 30 years, while precipitation, relative humidity and sunshine duration showed decreasing trends. In the last 30 years, the dates of three-leaf, tillering and booting of winter wheat in southeastern Tibet were delayed by 0.16 to 4.12 d·10 a^-1, while that of other growth periods were advanced by 0.41 to 4.42 d·10 a^-1, with the largest advance of the flowering period. The lengths of four growth stages, including tillering-turning green, booting-heading, heading-flowering, and milking-maturity, were shortened by 0.71 to 6.12 d·10 a^-1, while the lengths of the remaining growth stages were extended at the rate of 0.34-4.02 d·10 a^-1. Both the VGP and WGP lengths were shortened, while the length of RGP showed no response to climate change. The abrupt changes, occurring mainly at the beginning of the 21st century, were significantly detected in 67% of the growth period dates and 70% of the growth period lengths. The obvious decrease in the lengths of VGP and WGP of winter wheat was mainly attributed to significant increase in accumulated temperature of ≥0 ℃ in southeastern Tibet in recent 30 years, with a contribution rate of 24.2% and 24.7%, respectively. The milking-maturity period was the key period determining the length of WGP, with a contribution rate of 19.8%.

Key words: winter wheat, growth and development period, change trend, abrupt, southeastern Tibet.