Fffects Of Different Dehydrating Agents On Seed Dehydration And Vigor And Other Characters In Hybrid Rice Seed Production

Hybrid rice production has played an important role in the development of agriculture in China.If accelerating dehydration during seed maturation of hybrid seed production,it will bebenefit for reducing seed broken when harvesting mechanically,avoiding pre-harvest sprouting and so on.In this study,two hybrid rice varirties,Qianyou No.1 and Y Liangyou 689 were used to study the effects of different dehydration agents with diquat and paraquat as the main components on seed quality,physiological and biochemical changes during hybrid rice seeds maturity and physiological and biochemical changes,gene expression after seed storage.The main results were as follows:The effects of 11 kinds of dehydrating agents on seed dehydration and seed quality of hybrid rice production were studied.For Qianyou No.l,No.4,No.7 and No.9 agents had no adverse effects on the 1000-seed weight and seed quality.Five days after spraying dehydrating agents,No.7 agent decreased significantly seed moisture content by 3.1%No.4 agent and No.9 agent decreased significantly seed moisture content by 2.1%and 2.0%respectively,it suggested that the No.7 agent was a suitable seed dehydrating agent for Qianyou No.1 hybrid rice production.For Y Liangyou 689,No.7 and No.9 dehydration agents had no adverse effects on the 1000-seed weight and seed quality.No.7 and No.9 agents decreased significantly seed moisture content by 4.6%and 3.6%when the seeds were harvested 5 days after spraying dehydrating agents.No.7 agent had better effect in decreasing seed moisture content than that of No.9,it suggested that the No.7 agent was a suitable seed dehydrating agent for Y Liangyou 689 hybrid rice production.The effects of 11 kinds of dehydrating agents on physiological and biochemical characteristics in hybrid rice seed production were studied.The changes of soluble sugar,soluble protein,starch,hormones and antioxidant enzyme activities in Qianyou No.1 hybrid rice seeds were measured after spraying dehydrating agents.The soluble sugar content of the seeds treated with No.7 and No.9 agents decreased gradually from 0 to 5 days after spraying and then remained stable.The soluble protein content increased gradually from 0 to 7 days after spraying and then decreased.The contents of ABA and GA3 decreased gradually from 0 to 9 d after spraying.The activities of antioxidant enzymes remained high level from 0 to 9 d after spraying.The effects of dehydrating agents on storage substance,enzyme activities,hormone and related gene expression of hybrid rice seeds after storage were studied.For Qianyou No.1,seeds harvested 5 days after spraying dehydrating agents were storaged at room temperature for 6 months,there were no significant differences in the contents of soluble protein and ABA,and α-amylase activity between No.4,No.7 and No.9 agents and the control(without dehydration treatment but storage for 6 months).For Y Liangyou 689,seeds harvested 5 days after spraying dehydrating agents were stored at room temperature for 6 months,there were no significant differences in the contents of soluble protein and ABA,and a-amylase activity between No.7 and No.9 agents and the control(without dehydration treatment but storage for 6 months).Moreover,OsCYP707A5 related ABA resolving gene increased expression level,resulted in the decline of ABA content in seeds after storage,which might be one of the reasons for increasing germination from seeds treated by dehydrating agents after short storage.