| Maize(Zea mays L.),as a combination crop of food, feed, industrial raw materials, etc. with the rapid development of the processing and breeding industry, high quality maize are increasingly needed, while the high-quality special type of maize varieties is rarely found in China,so it cannot meet the demands for animal husbandry further processing. It has become the essential way to solve this situation by improving and creating high-quality special type germplasm resources and then future to cultivate new varieties. Therefore, the studying of maize quality molecular genetic mechanisms related to the traits will not only promote the selection of high-quality special type of new varieties and molecular marker-assisted selection, but also has great significance for the molecular mechanism to resolve quality-related traits such as grain starch formation. In this study, two groups containing 208 (Pop.l) and 197 (Pop.2) RIL were constructed from the cross Yu 82 maize inbred lines (as female parent) X Yu 87-1 and Shen 137and the phenotype were identified under different environmental conditions. Genetic linkage maps were constructed by SNP markers, mapping and analysis of QTL associated with four kernel quality traits were conducted by using composite interval mapping(CIM) method; QTLs with epistatic effects and -environmental interaction effects for two RIL populations by linear mixed model approach; By using BioMercator version 2.1 software, we integrated genetic linkage maps of two RILs population and by using meta analysis method we identified the consistency of QTLs analysis and future explored the molecular and genetic mechanisms and the genetic relationship between maize grain quality traits,which help to judge and select the stable main effect QTL to control maize grain quality traits.The major results are as follows:1. Under different environmental conditions, combined analysis of variance showed that F values of families among groups reached a significant level on crude starch, crude protein, crude fat and lysine in maize kernel., indicating that the true genetic differences between the various lines were existed in these two RIL populations; and all these contents ranged between two parents, perfoming the mid-parent heterosis (Except for individual points); Every quality traits showed one or both transgressive segregation.2. By using JoinMap 4.0 software two contains 1179 and 1116 SNP markers for genetic linkage map were constructed, the total length of the map in Pop.is 1884.85 cM, the average distance isl.60 cM, and the average genetic distance between two markers on chromosome 10 is around 0.92-2.13 cM 1; The total length of map is 1837.60 cM, the average distance is 1.65 cM, and the average genetic distance between two markers on chromosome 10 is between 0.92-2.57 cM in Pop.2. By integrating all of the markers in the genetic maps for these two RIL populations though using BioMercator 2.1 to, we got one genetic linkage map. containing 1689 SNP markers, which has a 1848.59 cM total length and the average 1.09cM distance.3. Under three different environmental conditions,we detected 34 QTLs related to maize grain quality traits from these two RIL populations. Among them22 QTLs were found in Pop.l, the contribution of individual QTL was 5.51-18.52% on chromosome 1,2,4,5,7,and 8 and the largest distribution located in the first chromosome, which has 8 QTL loci in Pop.l; 4 QTL in a combined analysis of location and condition was detected simultaneously in Pop.1.while in the Pop.2 12 QTL were detected, the contribution of individual QTL was 6.10-17.00%,and distributed on the chromosome 1,2,5,7,and 9, with the largest distribution in the 7th chromosome including 4 QTL loci; 3 QTL in a combined analysis of the location and were detected simultaneously.4. Using BioMercator version 2.1 software we detected 8 consensus of the QTL on four quality-related traits from two RIL populations,which are located in chromosome 2(2),5(2),7(2), and 8(2); mQTLs (mpQTL2-1, mpQTL2-2, mpQTL5-1, mpQTL5-2, mpQTL7-1, mpQTL7-2, mpQTL8-1, mpQTL8-2) comprises an initial QTL contribution rate above 10% and has been detected in one location and condition of the combined analysis of these regions which are hotspot region to regulate the maize grain quality traits:PRO1-8-1 located between PZE-108017379-PZE-108018815 on Chromosome 8, qLYS 1-2-1 presented between SYN32408-SYN27033 on chromosome 2, qpLYS2-5-1 found between PZE-105067019-PZE-105079533 on chromosome 5, and mapped the new QTL loci which showed a higher stability and contribution rate:qzPRO1-1-1 of PZE-101001044-PZE-101001107 on chromosome 1, qpOIL2-7-2 of PZE-107137587-PZE-107137996 on chromosome 7, the qLYS1-2-1 of SYN32408-SYN27033 on chromosome 1, qnLYS1-7 of PZE-107009674-SYN20419 on chromosome 7, qLYS 1-1-1 of SYN15084-PZE-101213558 on chromosome 1, qLYS1-5-1 of PZE-105157980-SYN7969 on chromosome 5, qLYSl-8-1 of PZE-108017379-PZE-108018815 on chromosome 8. |
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