Research Of Pure Lines Breeding On Herbicide-induced Parthenogenesis In Maize

In order to provide a reference for the use of herbicides to induce maize parthenogenesis pure line breeding technology and the improvement,innovation and utilization of maize germplasm resources.In this experiment,herbicides(trifluralin,glyphosate,glufosinate)were used as inducers,and hybrids of temperate and tropical blood were used as test materials.Three concentrations of 40,80,and 160 ?mol/L were set,and distilled water was used as a control.To study the induction rate of different inducers at different concentrations on Parthenogenesis of maize,and the induction rate of herbicides on different genotype corns was analyzed,and select the best treatment agent and the corresponding best treatment concentration.Field identification of the induced one generation(Pa1)and induced second generation(Pa2)plants,to determine parthenogenetic pure lines,use 20 K SNP chip for genetic diversity analysis of the pure lines.The main findings are as follows:1.Different concentrations and different herbicides have different induction effects.The average fruiting plant rates of glufosinate in Hainan winter in 2018 and Guizhou spring in 2019 are 8.81% and 9.10%,respectively,and the average soliding rate of glyphosate is 8.10% and 8.60%,respectively,and the average fruiting strength of trifluralin plant rates were 7.85% and 7.72%,respectively.Glufosinate had the best induction effect on maize parthenogenesis,followed by glyphosate,and trifluralin was the worst;and the same herbicide in different locations and different seasons induced corn parthenogenesis,the induction effect is basically stable.Both glyphosate and glufosinate had the highest average fruiting plant rate at 80 ?mol/L,3.30% and 2.76%,respectively;40 ?mol/L trifluralin had the highest average planting rate at 1.9%.That is,treatment concentration of 80?mol/L glyphosate and 80 ?mol/L glufosinate has the best induction effect,and the trifluralin treatment concentration of 40?mol/L can obtain better induction effect.2.The rate of herbicides to induce maize from different germplasm sources was obvious different.The average seed setting rate of temperate germplasm in Hainan in winter 2018 and Guizhou in spring 2019 is 10.82% and 9.33%,and tropical germplasm is 4.83% and 7.32%,respectively.The results of two locations in two years experiments showed that the rate of herbicide induced temperate germplasm was higher than that of tropical germplasm,and tropical materials may be more suitable for induction treatment in Guizhou.3.The frequency range of obtaining pseudo-pure lines after the herbicide induction treatment is 4.12%~6.63%,with an average of 5.31%,and the frequency range of obtaining pure lines is 0.36%~3.30%,with an average of 1.44%,that is,an average of 69 per treatment one female ear may acquire a pure line.The frequency of the pure line of induction combination GD932/NP5213 is the highest,which is 3.30%,which is equivalent to the treatment of 30 female spikes to obtain one pure line.4.Using 20 K SNP,a total of 16 parthenogenetic material and obtained its 12 parents were analyzed for genetic diversity.The results of cluster analysis can be divided into two categories: the first type is represented by the typical Suwan inbred line QR273,including A1~A11 tropical blood parthenogenetic lines and 9 parents.The second type is represented by the Reid group maize inbred line PH6 WC,which contains 3 parents and 5 temperate consanguinity parthenogenetic lines with A12~A16.The genotype analysis shown in the figure shows that the homozygosity of the self-breeding 2 generations of maize parthenogenesis breeding line induced by herbicides can reach 85.46% ~ 96.24%,which is equivalent to the efficiency of conventional breeding 5 generations;A1,A2,A3,A4,A5,A6,A10,A11 and A12 are similar to the maternal materials,and A7,A8 and A9 are analogy to the paternal materials.5.The preliminary determination of the combining ability of the tropical blood line pure line obtained with the experiment and the typical temperate germplasm PH6 WC shows that the output of the A7,A3,A1,and A4 combination combinations all increased by more than 10% compared with the control,and increased by 23.42%,18.99%,11.39%,and 11.39%,respectively.Pure lines bred with this technique can be used and improved through the temperate / tropical heterosis model.In summary,the frequency of breeding pure lines using herbicide-induced maize parthenogenesis technology is higher,and the pure lines obtained have higher homozygosity and better combining ability.This technology has good utilization value.