| Maize ideal plant type breeding is one of the important ways to achieve high yield.Leaf angle is an important part of maize plant type.Therefore,it is of great significance to carry out genetic research on corn leaf angle and mining of related gene loci for corn breeding.In this study,a pair of high-generation sister lines L1(compact)and L2(flat-unfolded)with significantly different plant types were used as test materials to construct the F2 segregation population and related progeny materials.The quantitative trait separation analysis software was used to study the upper ear leaf folder The genetic laws of the horns were explored by the BSA method and the main QTL genes were mapped.The results will lay the foundation for revealing the genetic regulation mechanism of corn leaf angle and related gene cloning.The main research results obtained are as follows:1.The field phenotypes of the sister lines L1 and L2 showed that there were extremely significant differences in the angle of the upper leaves,the number of male branches,the length of the clover leaves,and the length of the ears in the sister lines(P<0.01),There is no significant difference in other traits.2.Set different planting densities for L1 and L2,The results show that planting density will cause some changes in the leaf angle,but this change will not affect the positioning results of leaf angle;With the increase of the density,the light transmittance of the upper ear layer,the ear layer and the lower ear layer gradually decreased.Under high density treatment(75,000 plants/hm2),the light transmittance of the upper layer of L1 increased by 12%compared with L2.Light transmittance increased by 11.6% compared to L2;Net photosynthetic rate(Pn),stomatal conductance(Gs),and transpiration rate(Tr)showed a downward trend with increasing density,and intercellular CO2 concentration(Ci)gradually increased.Under high density treatment(75,000 plants/hm2),the Pn value of L1 increased by7.9% compared with L1.3.The normality test and genetic model analysis were performed on the leaf angle of the isolated population,and the results showed that the leaf angle characteristics of the F2 population and F2:3 families accorded normal distribution;In the mixed genetic model of two pairs of major-genes+poly-genes,the heritability of the major-genes was 65.8% and 58.6%,respectively.Correlation analysis was performed on the data of the included angles of theleaves on the ears of the F2 population and F2:3 families.The results show that the correlation between the leaf angles of the first leaf to the fourth leaf on the ear is greater than 70%,so the average number of leaf angles on the four leaves on the ear is set as the target trait.4.Using the BSA method,linkage markers were screened on chromosomes 3 and 6,and F2 segregated populations were used to construct a linkage map for the two chromosomes.F2:3families verified the initial localization results.4.On chromosome 3,one major QTL locus q LA3.06 was detected to be related to the leaf angle trait.The LOD value of q LA3.06 was9.31 and the phenotypic contribution rate was 30.91%.On chromosome 6,Two QTLs were found to be related to leaf angle traits,q LA6.01 and q LA6.07,respectively.The LOD value of q LA6.01 is 3.29,the phenotypic contribution rate is 4.94%,the LOD value of q LA6.07 is 2.87,and the phenotypic contribution rate is 4.23%.5.The recombinant segment was used for molecular marker encryption of the localization segment,and q LA3.06 was located in the range of about 124.7 Kb between snym03 and snym26.Reference maize B73 genome AGPv4,6 genes were found in the localization segment,According to functional annotations and previous research results,GRMZM2G060216(liguleless2)can encode basic b ZIP protein,and may be involved in the correct initiation of leaf rings in young leaves,The liguleless2 mutant can make the leaves tongue and ears missing,and the leaves appear upright,thereby reducing the corn leaf angle.It is speculated that the liguleless2 gene is a candidate gene for q LA3.06. |
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