Effects of Chilling Injury on Rice Yield in Different Periods in Western Liaoning

In order to avoid effect of chilling injury on rice yield, and evaluate yield loss caused by chilling injury correctly, based on TRP-1000D artificial intelligence climate box, rice variety 90-35 was selected to be treated with chilling injury at jointing stage and heading stage, which was 5 °C and 3 °C lower than outside, respectively, and lasted for 5 days, effects of chilling injury at jointing stage and heading stage on panicle traits, yield components and yield of rice were studied．Experimental results showed that, except for A₂ treatment, which significantly increased number of full grains on primary branches of rice, the A₁、A₂、B₁ and B₂ treatments significantly reduced number of primary branches of rice compared to CK treatment, and other panicle traits were significantly reduced compared to CK treatment．A₂ has the most negative effect on panicle length and secondary branch number, and has the least negative effect on solid grain number of secondary branch．B₁ has the least negative effect on number of primary branches and secondary branches, but has the most negative effect on number of solid grains of primary branches and secondary branches．B₂ has the greatest negative effect on number of primary branches and the least negative effect on ear length．Except for A₂ treatment, which significantly increased yield, A₁、A₂、B₁ and B₂ treatments reduced rice yield, primary branch setting rate, and secondary branch setting rate compared to CK treatment．A₂ has the least positive effect on primary branch setting rate and significantly increased yield, while B₁ has the most negative effect on yield, seed setting rate of primary branch and secondary branch．After rice 90-35 was treated with different low-temperature chilling injury at jointing stage and heading stage, its panicle characters, yield and yield components were significantly or extremely significantly negatively affected．Appropriate low-temperature treatment at jointing stage could increase cold resistance of paddy rice, restore normal growth environment at later growth stage, and rice could quickly return to normal growth and grow better．