| Sweet waxy corn and waxy corn are the main types of fresh corn in my country.Because of their excellent taste and texture,they are loved by consumers and the demand is increasing.However,the content of lysine is low and the nutritional value is not comprehensive.In order to increase the lysine content of sweet waxy corn and waxy corn,improve nutritional quality,and create new materials for corn quality breeding,a high-lysine waxy corn inbred line WR1-1(o2o16)was selected as the donor parent in this study.,Sweet waxy maize inbred line WT1791 and waxy maize inbred line Jingnuo 6 are recurrent parents to construct backcross T population(WR1-1/WT1791//WT1791)and N population(WR1-1/jingnuo 6//jingnuo 6).Using molecular marker-assisted selection technology,the target gene selection of individual plants in the separated generations,combined with the field performance of the plants,select individual plants with excellent comprehensive traits,and self-add generations.The genetic background analysis of the innovative materials obtained,combined with lysine and The related quality analysis has created materials of different recessive mutation gene aggregation types to provide material support for maize quality breeding.The main findings are as follows:1.Using molecular marker-assisted selection technology combined with conventional breeding,successfully created 28 different types of special maize breeding materials.Among them,the constructed T population was screened to obtain13 different types of high-lysine sweet waxy corn materials,including 2 o2o16wxsh2 genes,6 o2wxsh2 genes,and 5 o16wxsh2 genes.The constructed N populations were screened to obtain different types of high-lysine sweet waxy corn materials.There were 15 copies of glutinous corn materials,including 4 copies of o2o16 wx gene,5copies of o2wxsh2 gene,and 6 copies of o16wxsh2 gene.2.Based on 440 pairs of SSR primers,105 SSR markers with good polymorphism among parents were screened,and genetic background analysis was performed on 13 materials(T1 ～ T13)obtained from T population screening.The background recovery rate was 78.09%～87.62%,the average background recovery rate is 82.31%,which is 7.31% higher than the theoretical value;the genetic background recovery rate of chromosome 7 where the o2 gene is located is between61.5%-95.8%,and the genetic background recovery rate of chromosome 8 where the o16 gene is located Between 66.7% and 100%,104 SSR markers with good polymorphism among parents were screened,and genetic background analysis was performed on 15 materials(N1～N15)obtained from N population screening,and the genetic background recovery rate was 76.21% ～ 85.57%,the average background recovery rate is 81.40%,6.40% higher than the theoretical value;the genetic background recovery rate of chromosome 7 where the o2 gene is located is between61.1% and 100%,and the genetic background recovery rate of the chromosome 8where the o16 gene is located The rate ranges from 61.8% to 88.2%.3.Perform quality analysis on 13 materials(T1 ～ T13)obtained from T population screening.The analysis results of 17 kinds of aminoacids showed that 2o2o16wxsh2 gene materials(T1 and T2)and 6 o2wxsh2 gene materials(T3 ～ T8)compared with the recurrent parent WT1791,asparticacid(Asp),glycine(Gly),and valine 6 kinds of aminoacids(Val),histidine(His),lysine(Lys)and arginine(Arg)were significantly increased,and the content of T1 and T2 lysine(Lys)were both0.92%,which increased 76.92%;the average content of T3～T8 lysine(Lys)is 0.78%,an increase of 50.00%,the increase is 48.00%～54.50%,the highest is T6 and T8,both as high as 0.80%.5 copies of o16wxsh2 genetic material(T9～T13),in which the content of T9,T11 and T13 lysine(Lys)were 0.59%,0.55% and 0.64%,respectively.Compared with the recurrent parent WT1791,they increased by 14.76%,6.18% and 22.74%,indicating that o2 and o16 gene introgression can increase the lysine content of sweet waxy corn.The analysis results of glucose,fructose and sucrose content showed that compared with the reincarnation parent WT1791,T1 glucose,fructose and sucrose were increased by 12.0%,12.5% and 9.2%,respectively.T4 glucose,fructose and sucrose were respectively Increased by 21.8%,28.1%,and11.4%;T3 glucose and fructose increased by 18.8% and 18.8%,T5 glucose and fructose increased by 12.8.% and 9.4%,respectively;T11 glucose and sucrose content increased by 18.2% and 10.1%,respectively.4.Perform quality analysis on 15 materials(N1～N15)obtained by screening of N population.The analysis results of 17 kinds of aminoacids showed that 4 o2o16 wx genetic materials(N1 ～ N4)compared with the reincarnation parent Jingnuo 6,aspartic acid(Asp),glycine(Gly),lysine(Lys)and arginine(Arg)4 kinds of amino acids increased significantly.The average content of lysine(Lys)was 0.46%,an increase of 53.33%,the increase was 48.77%-63.87%,and the highest was N4,up to0.49%;5 copies of o2 wx genetic material(N5～N9)Compared with the reincarnation parent Jingnuo 6,the five aminoacids aspartic acid(Asp),glycine(Gly),histidine(His),lysine(Lys)and arginine(Arg)increased significantly.The average content of Lys was 0.41%,an increase of 36.67%,an increase of 30.57%-48.27%,and the highest was N7,which was as high as 0.44%.Compared with the reincarnation parent Jingnuo 6,5 copies of o16 wx genetic material(N10 ～ N15),Serine(Ser)and(methionine)Met two aminoacids increased significantly,indicating that waxy corn is significantly regulated by the o2 gene,and the simultaneous infiltration of o2 and o16 genes can further increase the lysine content.The analysis results of starch,total protein and oil content show that N1 ～ N15 amylopectin/total starch is between97.65% and 98.80%,which all meet the national standard of waxy quality(95%);the total protein content is comparable to the reincarnation parent Jingnuo 6(11.26%),among which N6,N14 and N15 are increased by 2.8%,2.2% and 5.6% respectively;the oil content is between 2.65% and 3.43%,which is significantly increased compared with the reincarnation parent Jingnuo 6(2.43%). |
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