Identification Of Cold Tolerance Of High Quality Rice Varieties In Eastern Jilin Province

The experiment was carried out in the pot experiment in the Academy of Agricultural Sciences of the Yanbian Korean Autonomous Prefecture from 2019 to 2020.10 new high-quality japonica rice varieties in and out of Jilin Province were used as test materials,and low temperature stress treatment was performed at the bud,seedling,tillering,meiosis,and filling stages.The light intensity inside the artificial climate box was simulated in natural overcast and rainy conditions for 12 hours each day and night.Rice was grown under intelligent greenhouse conditions as a control.The cold tolerance of the germination rate and dead seedling rate was identified at the bud and seedling stage.The study of physiological growth characteristics,yield components,and quality effects was conducted at the division stage and the filling stage to provide scientific basis for the prevention of cold damage and selection of high-yield and high-quality varieties in Yanbian.1.Longdao 18,Jijing 816,and Suijing 14 with strong cold tolerance during germination have been screened;Yanjing 22 has strong cold tolerance.Jijing 515,Jijing 809,Tongxi 935,Tongxi 933,and Jiyujing with strong cold tolerance at the bud stage were screened.2.Plant height,tiller,and chlorophyll content changed significantly after tillering under low temperature stress.Among them,the growth rate of dragon rice 18,Tongxi 933,Yanjing 22,Jiyujing,and Tong 35 was faster than normal,the number of tillers of Longdao 18,Tongxi 933,Yanjing 22 and Jiyujing increased rapidly,the chlorophyll content of Jijing 809,Jijing 816,Tongxi 933 and Jiyujing recovered quickly in the early stage.The changes of protective enzymes in leaves of different cultivars under low temperature stress varied greatly.After low temperature stress at seedling stage,Longdao 18,Tongxi 935,Jijing 816,Suijing 14,Yanjing 22,and Tong 35 had stronger enzyme activities and after low temperature stress at the tillering stage,the enzyme activities and increase of Longdao 18,Jijing 816,Tongxi 933,and Yanjing 22 were stronger and after low temperature stress during meiosis,Longdao 18,Jijing 816,Suijing 14,and Tongxi 935 had stronger enzyme activity and increase and the enzyme activity and the increase rate of Jijing 816,Yanjing 22,Suijing 14 Jijing 511 were stronger after low temperature stress during the filling stage.The CAT,POD,and SOD enzyme activities of rice were all increased under low temperature stress.Some of these varieties had strong SOD enzyme activities,which increased in all periods,while the CAT and POD enzyme activities differed between varieties at different periods.3.Different breeds in different periods caused reduced yield after being subjected to low temperature stress.In terms of yield components,the number of ears,grains per ear,seed setting rate,and thousand-grain weight were all affected to varying degrees,resulting in reduced rice yield and a significant increase in empty grains.The varieties that were less affected by delayed chilling injury yield were Longdao 18,Yanjing 22,Suijing 14,Jijing 816,and Tongxi 933.The varieties that were less affected by obstacle chilling injury yield were Longdao 18,Yanjing 22,Suijing 14,Tong 35.4.Different varieties and low temperature stress have great influence on the nutritional quality of rice.In particular,when low temperature stress is encountered during the grain-filling maturity period,it will affect the development of the grains and thus have a greater impact on amylose content.Among them,Tongxi 935,Longdao 18,Jijing 515,and Jijing 809 had relatively low protein or amylose content and good quality.