Genetic Analysis Of Plant Architecture Traits And Fine Mapping Of QPH5.04 In Maize

Reasonable plant type can effectively increase maize planting density and yield per unit area.It is of great significance to analyze the genetic basis of maize plant architecture and excavate important locus genes.In the early stage of this study,Ye478 was used as the recipient parent and Qi319 as the donor parent,and 200 molecular markers were used to construct a set of chromosome fragment substitution lines containing 180 families.Using the RIL population constructed by Ye478 and Qi319,it was identified that there were major QTLs controlling plant height in bin5.04 region,while CL86 contained the genome segment of Qi319 donor in bin5.04.In this study,the phenotypic analysis of chromosome segment substitution lines in three environments in 2018 was carried out,and the genetic analysis of plant height,leaf angle,leaf width,leaf length and leaf area was carried out to find out the chromosome regions and their distribution rules regulating plant architecture traits in maize.At the same time,F2 segregated population was constructed by CL86 and Ye478,and the main QTL q PH5.04 controlling maize plant height by fine mapping of trans-superimposed lines was screened.The results are as follows:1.Five plant architecture traits including plant height,leaf angle,leaf width,leaf length and leaf area were analyzed in three environments.A total of 83 QTLs were detected,including 20 plant height,19 leaf angle,14 leaf width,14 leaf length and 16 leaf area.26 QTLs were detected in three environments,and 17 of them controlled at least two plant architecture traits.In the bin1.03-1.04 and bin8.01 regions,the QTLs controlling plant height,leaf length and leaf area were detected simultaneously;in the bin1.06 and bin8.09 regions,the QTLs controlling leaf angle,leaf width and leaf area were detected simultaneously;and in the bin2.08 region,the QTLs controlling leaf width,leaf length and leaf angle were detected simultaneously.2.In summer of 2017,q PH5.04 was initially located by F2 segregated population containing 312 individual plants;in winter of 2017,q PH5.04 was relocated by F2 segregated population containing 581 individual plants;in summer of 2018,q PH5.04 was validated by F2 segregated population containing 1098 individual plants;nine types of recombination architecture exchange individual plants were screened out to construct cross-overlapping line fine mapping q PH5.04,which will eventually be the target.The marker QTL was locatedbetween M5-12 and M5-20,and its physical location was 168,712,169 bp-170,067,158 bp,about 1.35 Mb(refer to B73 genome AGPv3).Twenty candidate genes with functional annotations were identified from the maize genome database(http://www.maizegdb.org/).According to functional annotations,Zm00001d016735 encodes SMAX1-LIKE protein,participates in the regulation of signal transduction of monocrotaline,and also affects auxin and cytokinin transport.