Construction Of A SSSLs In Maize And Analysis The Plant Traits As Well As Its Heterosis

Abstract:Single segment substitution lines(single segment substitute line,the SSSLs)is an important secondary mapping population which is a good material for genetic analysis,in particular,QTL analysis.In this study,chang7-2 is the donor parent and 1x9801 is the receptor parent,we build the genetic background of 1x9801 of the Chang 7-2 chromosome single segment substitution lines(Single segment substitution lines,SSSLs)groups with affinity of this hybrid,backcross,and SSR(Simple Sequence Repeats)method of molecular markers to track the donor chromosome segment.We have analysis about the donor gene composition trends in process of the build of SSSLs,and carry out QTL analysis of plant traits and heterosis of maize fields.The main findings are as follows:1.A total of 107 homozygous SSSLs and 115 CSSLs are got after four generations of backcross and three generations of selfing,combined with the SSR marker-assisted selection.The total length of 107 SSSL fragment is 3161.98cM and the average length is 29.55cM,covering genome 2819.79cM,the coverage rate is 34.90%.107 substitution fragment length is between 2.38cM?179.42cM,mainly distributing in 1.00cM?50.00cM within 91 accounting for 85.4%of the total;the substitution fragment length distribution between 1LOOcM?10.OOcM is up to 28,accounting for 26.17%;fragments which are greater than 50.00cM only is 16,accounting for 14.95%of the total.In the 115 CSSL material,two fragments of 71 accounted for 61.74%,three fragments of 30 accounted for 26.09%,four fragments of 11 accounted for 9.57 percent,five fragments of three accountied for 2.16%.2.In the present study,32 SSSLs were identified in controlling of plant height.we speculated that contains the 27 QTLs associated with plant height due to the substitution fragment overlap,29 SSSLs correlation ear high contain 21 ear height QTLs,there are four SSSLs which present significant differences performance in plant height and ear height between zhengzhou and xunxian.12 SSSLs plant height are different with the control in detected significant performance,11 SSSLs ear high are different with control,there are 4 SSSLs which their plant height and ear height are significant differences with control,indicating that the phenotype of the two pilot sites SSSLs groups present stability.The tag umc2165-umc2166-bnlgl136 section in 6.07 district,where a SSSL in plant height,ear height achieve a very significant difference with control between two points.We predict a main-effect QTL exist in controlling plant height and ear height.3.We detect five plant height QTL from the Zhengzhou and Xunxian in 58 CSSLs,which could explain the phenotypic variation between 6.14%-9.24%and 3 ear height QTL for explaining phenotypic variance 6.94%-8.77%;the QTLs which are linkage with mark phi083 umc1492 are also detected the relevant fragments in SSSLs.Comparing with traditional methods such as t-test,Windows of QTL IciMappingv2.0 can detect QTL for the small number,but the positioning is more accurate,higher credibility.Smaller cssl groups and selected lower marker density,it may be detected by overlapping fragments that the target traits are not precise enough and the corresponding need further investigation to prove indoor mark whether these QTLs is indeed correlate to ear height and plant height.4.We find 19 SSSLF1s in plant height with the control show the excessive advantage in the scope of-8.78%-9.87%,27 SSSLF1s ear height with the control show excessive advantage in the scope of-13.18%-16.70%,19 SSSLF1s silking stage show excessive advantage with the control in the range of-4.58%-5.94%,14 SSSLF1s the shedding with control show the excessive advantages in the scope of-4.13%-5.91%.We find a SSSLF1 in 1.08 district show the excessive advantage in plant height for 9.88%?ear height for 16.02%?silking stage for 3.35%and shedding for 6.44%with control,We detected 16 QTLs with plant height exceeded advantage,22 QTLs with ear height exceeded the advantages,17 QTLs with the the silking excessive advantage,13 QTLs with shedding excessive advantage.Because some substituted segments are overlap,we can assume that the QTL controlling the trait exists in the overlap of two fragments if the additive effect in the same direction,shorten the length of the target fragment for further fine mapping.Some fragments may also be a result of several minor QTL together,so we need to verify whether the fragment contain the major QTL by building subgroups.