Screening And Evaluation Of New Chemical-gametocide In Rapeseed(Brassica Napus L.)

Chemical gametocide induced male sterility is an approach to utilize plant heterosis,which is the most direct and effective method to produce hybrid generation on a large scale.So far,there are few kinds of chemical gametocidal agents in Brassica napus L.,and some of them are not very well.In recent years,our laboratory has found that most sulfonylurea herbicides have gametocidal effect on Brassica napus L.,and we can start with this kind of herbicides to develop new chemical androxicidal agents for Brassica napus L.Some acetolactate synthase(ALS)inhibitory herbicides,such as tribenuron-methyl,have been successfully used as chemical hybrid agents in Brassica napus L.hybrid production,but because tribenuron-methyl has gametocidal effect on different varieties under different climatic and different environmental factors.Therefore,it is necessary to continue to screen new chemical hybrid agents.In order to screen new chemical hybrid agents,four new herbicides were used in this experiment,and several 13 rapeseeds(Brassica napus L.)varieties were treated with two concentrations,and two kinds of pesticides which might be used as chemical hybrid agents for Brassica napus L.were selected.Then the efficacy of these two drugs and the other three drugs selected in the early stage were evaluated on different varieties.The main test results are as follows:1.In 2018,imazapic at the concentration of 0.5 to 1 mg/L and trifloxysulfuron-sodium at the concentration of 2.2 to 4.4 mg/L had a better gametocidal effect on 13 rape varieties,and the sterility rate of the 13 rape varieties was more than 80%,and the male sterility rate of 13 rape varieties was more than 80%,and the male sterility rate of 13 rape varieties was more than 80%.However,penoxsulam and ethoxysulfuron had no gametocidal effect even if the drug damage produced by Brassica napus L.was more serious.However,these four agents had obvious inhibitory effect on ALS of Brassica napus L.,which indicated that the agents that could inhibit the activity of ALS did not necessarily have the effect of killing male.2.The above four agents had a great effect on the ALS activity of flower buds,but had little effect on the enzyme activity of old leaves.The results showed that flower buds were more sensitive to pesticides.2.4 mg/L concentration of imazapic and 2.2mg/L concentration of trifloxysulfuron-sodium could abort stamens but had no significant effect on pistil of rape.3.In 2019,it was found that the gametocidal effect of different agents on different rape plants was different: after treatment with 1.1mg/L concentration of trifloxysulfuron-sodium and 1.5mg/L concentration of oxasulfuron,The sterility rate of all varieties was above 90%,but the drug damage was more serious.The sterile plant rate of F341 and D699 varietiestreated with imazapic at 2.4mg/L concentration was above 90%,and there was no obvious drug damage.Sterility rate of H15,Z267 and D699 varieties treated with 1.5mg/L concentration of flazasulfuronl and 1.225mg/L concentration of triflulsulfuron-methyl were above 90%,and there was no obvious drug damage,but the pistil of each plant after treatment with triflulsulfuron-methy became shorter.4.Using tribenuron-methyl mutant K5 and DS3 as male parents and common inbred line ZH9 as female parents,simulated experiment of hybrid seed production was carried out in small cages covered by nylon net.Both the female and male parents were sprayed with several gametocides.ZH9 × K5 spraying 1.1 mg/L concentration of trifloxysulfuron-sodium resulted in male sterility or semi-sterility,and the seed setting of female parents was very poor.After spraying 0.225mg/L concentration of tribenuron-methyl with ZH9 × K5,the male parents K5 was normal,the female parents ZH9 was completely male sterile and the seed set was good.The male parents DS3 was slightly male sterile after spraying 1.1mg/L concentration of trifloxysulfuron-sodium sodium,and the female parents ZH9 had chemical damage and poor seedset.After spraying 1.2mg/L concentration of imazapic with ZH9 ×DS3,the male parents DS3 was normal and the female parents was sterile,which means the seed setting is good.