Genetic Diversity Of Maize P18-7 Related Lines And Analysis Of Traits Of Their Offspring

The experiment mainly used the SSR molecular marker method to analyze the genetic diversity of 26 maize P18-7 relatives and 7 test species.The UPGMA cluster analysis method was used for preliminary clustering,and the genetic relationship of 33 maize inbred lines was preliminary.Divide and combine the field test results and SSR molecular marker results,select 10 from the 26 P18-7 relatives as the test line and 7 test species,use NC? design,set up 70 cross combinations,pass one year The two-point joint identification was conducted to study the general combining ability of 13 main agronomic traits of 17 maize inbred lines,special combining ability of 70 hybrid combinations,total combining ability of yield and heterosis,grain moisture content and dehydration rate.The main research results as follows:1.A total of 119 alleles were detected in 26 pairs of SSR primers.The variation range of the loci detected by each pair of primers ranged from 2 to 7,with an average of 4.57.The polymorphic information content(PIC)of each SSR marker site ranged from 0.3802 to 0.8402,with an average of 0.687.According to the database established by the SSR marker results,the genetic similarity coefficient(GS)between 33 maize inbred lines was calculated using NTSYS 2.10 e software,and the variation range of GS was 0.3076 ? 0.9038,with an average value of 0.6193.According to the UPGMA cluster analysis method,the 33 inbred lines were initially clustered.Based on the genetic distance of 0.57,they can be divided into 6 categories.2.The results of the joint analysis of variance showed that in the inner block of the location,traits reached very significant differences except for the male flower branch,the number of leaves of the whole plant,the length of the bald tip,the yield per plant and the 100-kernel weight.Among the locations,except for the ear thickness and the number of grains in the rows did not reach a significant difference,other traits reached a significant difference,indicating that most of the traits are obviously affected by the ecological environment and regional conditions.Between the combinations,all traits reached extremely significant levels,indicating that there are real genetic differences between the hybrid combinations.In the location × combination interactions,except for the stem thickness did not reach a significant level,other traits reached significant differences,further indicating that the interaction between genes and environment has an effect on 12 traits such as plant height and ear height.3.Among the 10 tested lines,6 of them have a positive effect,indicating P18-7,P18-3,15-6,P343,PH6 WC,and P337 have great potential for using.The comprehensive analysis of GCA of other agronomic traits showed that P18-7,P18-3,and 15-6 have more using potential in Guizhou screened out of 10 tested lines,and their utilization potential was P18-7> P18-3> 15-6.4.The analysis using the top ten combinations of the two-point yield SCA of 70 combinations shows that the output SCA has a relatively large range of relative effect values,and its SCA value ranges from-18.69 to 19.51,of which 35 combinations show a positive effect,p343 × Su 37,p18-7 × Su 37,15-6 × P-162,15-7 × Dan 340,PH6 WC × Dan 340,PH6 WC × 78599141,P117 × P-162,120 × Anlk01-1,p337 × 78599141,173 The SCA of 10 combinations including × 7859914 is higher,and the production GCA of inbred lines 15-7 and Dan 340 all show negative effects,but the production SCA of 15-7 × Dan 340 ranks fourth,which can be seen There is no inevitable connection between the yield of the hybrid combination SCA and the GCA of the parents.Only when the GCA of both parents is higher and the SCA between the two parents is also higher,the high-yield hybrid combination can be selected.5.TCA and heterosis model analysis were conducted on the yield of 70 hybrid combinations,of which 41 combinations had positive TCA effect values and 29 combinations were negative.The top ten in output TCA are: P343 × Su 37,P18-7 × Su 37,15-6 × P-162,P18-3 × W527,P18-3 × P-162,15-6 × Su 37,PH6 WC × Anlk01-1,P117 × P-162,P337 × W527,PH6 WC × Dan 340.The TCA effect value performance of the yield of the hybrid combination is consistent with the yield performance result.The larger the TCA effect value,the higher the yield of the hybrid combination.The variation range of yield is between 337.84kg-612.64 kg,the highest is P343 × Su37.The heterosis model analysis of the top 10 hybrid combinations of yield,the heterosis models of these combinations can be roughly divided into P343 and P18-7 and Suwan tropical germplasm,15-6 and P117 and improved Reid,PH6 WC and 15-7 with Luda Red Bone,PH6 WC,P337 and 173 with 78599,120 and PH6 WC with Lancaster and P18-3 and P337 with Guizhou local germplasm selection It is a heterosis group with potential utilization value.6.Correlation analysis of the genetic distance obtained by SSR molecular markers and the yield of hybrid combinations and other agronomic traits SCA shows that,for the top 10 hybrid combinations with good potential,the genetic distance of SSR molecular markers is related to male flower branch,number of ear rows,and ear thickness.It showed a significant positive correlation with the yield per plant,and the correlation coefficients were 0.46,0.42,0.38,and 0.31,respectively.However,it showed a significant negative correlation with the spike length and bald tip length,and the correlation coefficients were-0.64 and-0.61;the other traits show no obvious correlation.7.Analysis of the grain moisture content and dehydration rate of 70 hybrid combinations shows that the grain moisture content and dehydration rate both gradually decrease with the increase of days after pollination,but there are significant differences due to different genotypes of varieties.After 46 days of pollination,the average moisture content ranged from 22.8% to 34.5%,and the minimum value of grain water content was less than 40%,indicating that 46 days after pollination,the physiological maturity period has been completely entered.After pollination for 53 days,the average moisture content ranged from 19.30% to 30.60%.The combination with the lowest grain moisture content during harvest was P117 × Huangzaosi,followed by the combination with lower water content: P18-3 × Huangzaosi,120 × Huangzaosi,15-7 × Huangzaosi,P337 × Huangzaosi and PH6 WC × Huangzaosi.According to the calculation results of grain dehydration rate in different periods after pollination,the range of grain dehydration rate after pollination is 2.01% / d,the range of change from 32 to 39 d after pollination is 1.68% / d,and the range of change from 39 to 46 d after pollination is 1.18 % / d,the change range from 46 to 53 d after pollination is 1.29% / d.With the increase of days after pollination,the dehydration rate of grains gradually decreases,and the fitting equation of the average change trend is y =-0.464 x + 2.474,R2 = 0.930.