|
Crop height, quality, and many other agronomic traits are mostly complex quantitative traits. In recent years, with the development of biotechnology, the use of molecular markers for QTL controlling these traits number of locations on the chromosome and genetic effects were studied and analyzed, and made some progress. Unfortunately, the current study reported mostly F2, BC1, DH and RIL population for the study, because the genetic background of these groups is more complex and difficult to fundamentally improve the accuracy of QTL mapping, but also makes it difficult to accurately related QTL effect estimates. Chromosome segment substitution lines refers to a set of the same parent as the genetic background, the replacement of the donor parent chromosome fragments of one or a few lines consisting of groups. Due to its genetic background than a single, can greatly improve the quantitative trait loci for complex positioning accuracy, and by building a secondary population can achieve the target QTL fine mapping. In this study, two sequenced rice varieties as materials, the use of high-generation backcross and marker-assisted selection combined method to construct a set of \chromosome segment substitution lines groups, and for rice quantitative trait genes related to a comprehensive analysis in order to discover and further fine mapping and positional cloning of new QTL for seats for the use of molecular marker-assisted breeding traits of rice lines and rice functional genomics basis for the study. The main results are as follows: 1) from the public database developed from 153 pairs of SSR primers screened out evenly distributed in the rice chromosome 12, 104 pairs of SSR polymorphic primers polymorphic ratio was 68.2%. Using relatively evenly distributed in the 12 chromosomes of rice which 104 pairs of primers molecular marker linkage map was constructed, the rice genome map covering 1494.0 cM, average distance between markers was 14.37 cM. For the analysis of BC4F1 plant genotype and the use of molecular marker-assisted selection target plant. 2) the use of 104 pairs of polymorphic SSR markers detected BC4F1 plant genotype, select heterozygous genome fragment fewer seeds per plant, planting obtain BC4F2 populations, re-use target markers genotyped BC4F2 communities and, ultimately, 122 CSSL. The average estimate of CSSL replacement fragment length of 23.4 cM, most located 1-15 cM ,16-30 cM and 31-45 cM range, respectively, 43, 46 and 21; replacement segment of greater than 45 cM There are 12. 122 CSSL distributed in 12 chromosomes, from 4 and 6 on chromosome 11 to chromosome 6, 16, with an average 10.2 per chromosome replacement segment. Replacement segment substitution lines of a total length of 2854.4 cM, equivalent to the size of the rice genome 1.9 times, the replacement of rice genome fragments covering a total length of 1301.8 cM, the average coverage of 86.7%. 3) to 94 CSSL populations as experimental material analysis CSSL groups and parents long rice (milled rice length, MRL), long rice (cooked rice length, CRL) and cooked rice elongation (cooked rice elongation, CRE). Using the substitution mapping method of positioning a 12 grain elongation associated with QTLs. These QTLs located on rice chromosome 3,4,6,8 and 9, in which two MRL QTLs located on chromosome 3, a MRL QTL located on chromosome 8; 4 CRL QTLs located on chromosomes 3,6,8 and 9; 5 CRE QTLs located on chromosomes 4,6,9,10 and 11. Extension of the additive effect of the QTL ranged from -5.80 ~ -0.14, additive effect percentages -1.72% -12.26%, which qCRE-6 additive effect bigger. QTL for grain elongation Identification and preliminary positioning for its further fine mapping and molecular marker-assisted selection (marker-assisted selection, MAS) laid the foundation for improving rice quality. 4) to 94 CSSL populations as test material, investigation and analysis CSSL groups and parents panicle length. The results show that: In the 17 substitution lines detected in eight control rice panicle length QTL, 9, and are located on chromosome 11; mapping using the substitution method, the positioning of which 8 a panicle length QTL; their additive effect ranged from 0.10 to 3.20, which qPE-9 and qPE-11 additive effect is larger, the average effect size was 3.15 and 2.95, respectively, showing the main effect genetic characteristics; qPE-2-2, qPE-3-1, qPE-3-2, qPE-7 and qPE-8 and other five QTL is positioned within the section is less than 10.0 cM. CSSL can effectively identify the use of rice panicle length QTL, these QTL marker-assisted breeding for the panicle rice lines of moderate length and its further fine mapping foundation. 5) to 94 CSSL populations as experimental materials to P ≤ 0.01 as the threshold, the heading for the replacement segment QTL were identified. Substitution mapping method using co-localization of the four control rice heading date QTL, respectively, located on chromosome 4, 5 and 8 Zi; QTL additive effect is-6.4 - 2.7, additive effect percentages - 6.4% ~ -2.7%; qHD-3 and qHD-8 additive effect is large, the performance characteristics of major genes. To further positioning qHD-3 and qHD-8, in the target area encryption 16 pairs of SSR primers, qHD-3 and qHD-8, respectively, are defined in the third chromosome RM3166 and RM16206, RM4085 and RM8271 on chromosome 8 between the genetic distance were 13.9 cM and 6.4 cM. The result is improved marker-assisted selection laid the foundation for growth period of rice. 6) use in 9311 and built 94 Nipponbare chromosome segment substitution lines as materials, substitution mapping method to control the reaction of phenol rice grains were three QTL localization. The results showed that four chromosome segment substitution lines material phenol reaction level 4, the rest in between 0-1. Which contain eight substitution lines derived from Nipponbare a replacement segment. 3 responsive genes in rice phenol qPH4-1, qPH2 and qPH7 is defined in section 2 chromosome RM406 and RM240, RM280 and RM5709 on chromosome 4 and 7 chromosomes between RM11 and RM6574, genetic distances of 12.9 cM, 9.5 cM and 16.0 cM. qPH4-1, qPH2 and qPH7 identification and preliminary positioning for further fine mapping and positional cloning of the foundation. This study confirmed that the use of constructed CSSL communities related QTL analysis is feasible and effective.
|