Study On The Regulatory Effect Of Green Control Agent On High-Stalk And High-Quality Small-Seeded Peanut Cultivar

Anhua red-skinned small-seed peanut has excellent quality and has become a national geographical indication agricultural product in 2019,but the plant height reaches 65-70cm,which is easy to lodge,which is not conducive to mechanical and manual harvest,and has few branches and low yield.In order to reduce plant height,prevent lodging and increase yield,ethephon and uniconazole recommended by the national agricultural industry standard"guidelines for the use of Green Food pesticides NY/T393-2018"were adopted.Two chemical control agents with different concentrations（ethephon 150mg/L,200mg/L,uniconazole 20mg/L,30mg/L）were sprayed at seedling stage,flowering stage and podding stage,the chemical control experiment was carried out with clear water as control.The field cultivation method was used to study the effects of ethephon and enoxazoli on plant morphology,photosynthesis,fluorescence,yield,kernel quality and stem lodging resistance,analyze the differences among different treatments,and comprehensively evaluate the results.To explore the best period and concentration of chemical control agents,to provide a theoretical basis for high-yield and high-quality cultivation and quality improvement of peanut.The main results are as follows:1.The two chemical control agents had obvious effects on the growth and development of peanuts.Enrithine and uniconazole significantly decreased the plant height and lateral branch length of peanut,while reducing the leaf area,increasing the root-shoot ratio and economic coefficient,and significantly reducing the vegetative body/reproductive body（V/R）ratio at maturity.Among them,ethephon sprayed at a concentration of 150 mg/L at the flowering needle stage（E3 treatment）had the best effect on controlling vigorous growth and improving the root-shoot ratio,and spraying at a concentration of 200 mg/L at the pod setting stage had the best effect on reducing the vegetative body/reproductive body（V/R）ratio,the effect of improving the economic coefficient is the best;the height control effect of uniconazole is better than that of ethephon,spraying 30 mg/L concentration（U4 treatment）at the flowering needle stage had the most obvious inhibitory effect on plant height and lateral branch length,which were shortened by 30.71%and 24.56%compared with the control,respectively,at the pod setting stage,spraying at a concentration of 30 mg/L had the best effect on reducing the ratio of vegetative body/reproductive body（V/R）,and had the best effect on root-shoot ratio and improving economic coefficient.2.The two chemical control agents could increase the chlorophyll content,net photosynthetic rate and stomatal conductance of peanut in the middle growth stage,and increase the Tr in the flowering stage and mature stage,but had no obvious regularity in the intercellular CO₂concentration.Among them,ethephon 150 or 200mg/L spraying at podding stage was more beneficial to increase chlorophyll content,and after uniconazole treatment,the chlorophyll content increased better under 20mg/L concentration at flowering stage.3.The two chemical control agents have different effects on chlorophyll fluorescence.Ethephon decreased the Fo and Fv/Fm values at the flowering needle stage and increased the Fm value at the pod setting and mature stages;while uniconazole decreased the Fo value at the flowering needle stage and increased the Fm and Fv/Fm values at the pod setting stage.Among them,the treatment of 150 mg/L ethephon and 30 mg/L niconazole at the flowering needle stage had the best effect on improving the maximum photochemical efficiency（Fv/Fm）at the mature stage,and the heat dissipation increased greatly,which was beneficial to the photosynthetic electron transfer.speed increase.4.The two chemical control agents have a good effect on improving the lodging resistance of peanuts,especially uniconazole,which can effectively reduce the height of the center of gravity of the peanut stem,increase the thickness of the stem,and increase the internode bending resistance and internode puncture.strength,improve the mechanical strength of the stem.Among them,after ethephon treatment,spraying at a concentration of150 mg/L at the flowering needle stage had the best effect on enhancing the stem thickness and internode flexural strength of peanuts,which were increased by 19.33%and 21.60%respectively compared with the control.The height of the center of gravity decreased most obviously by spraying 150 mg/L concentration,which was 26.89%lower than that of the control;Compared with the control,the stem thickness increased by 11.71%,45.45%and14.76%respectively,and the effect of spraying 30mg/L concentration on the height of the peanut center of gravity in the pod setting stage was obvious.The two chemical control agents had different effects on the cellulose content and lignin content in the base of the main stem at the mature stage.Among them,the content of cellulose and lignin was the lowest after spraying 200 mg/L of ethephon at the seedling stage,which was 4.56%and27.48%lower than the control,respectively;the content of cellulose and lignin was the lowest in the treatment of 30 mg/L of niconazole at the flowering needle stage,the 30 mg/L treatment at the pod setting stage had the best effect of increasing the contents of cellulose and lignin,which were 5.08%and 70.19%higher than the control,respectively.5.Chemical control agents have different effects on the yield and quality of peanut.Among them,the ethephon treatment did not increase the yield significantly or decreased the yield,and the higher yield was the 150mg/L treatment at the flowering stage,which increased by 11.08%compared with the control.The source of the increase was that the number of blighted fruits per plant was the least,while the weight of 100 fruits and 100kernels was the largest,slightly reducing fat and increasing protein.It shows that ethephon spraying must grasp the appropriate period in order to achieve the effect of increasing production.Most of the uniconazole treatments increased the yield,and the highest yield was the 30mg/L treatment at the podding stage,which increased by 17.33%compared with the control.the source of the increase was that the number of full fruits per plant was the most,the number of chaff fruits per plant was the least,the weight of 100 fruits was larger,and the weight of 100 kernels was the largest,slightly increasing fat and reducing protein.In summary,the yield-increasing effects of two green chemical control agents on Anhua red-skinned small-seeded peanut were mainly reflected in reducing plant height,increasing root-shoot ratio and economic coefficient,promoting the transport of matter from vegetative organs to reproductive organs,increasing 100-fruit weight and 100-kernel weight,and improving lodging resistance.but it has little effect on photosynthetic efficiency.Both of them should not be sprayed prematurely,which can easily lead to a decrease in yield or a small increase in yield due to the inhibition of plant growth and development.The yield and lodging resistance effect of uniconazole is better than that of ethephon.Finally,it is recommended that 30mg/L uniconazole is sprayed at podding stage（U6 treatment）to increase yield,At the same time,the plant height decreased significantly,and the lodging resistance was improved,which was more beneficial to mechanized production.