| Wheat yield is comprised by Spike number per acre, Grains number per spike and Thousand grains weight. And increase of yield by improving the three yield components is one of the important targets in the wheat genetic and breeding reaearch. So, it is very important to the effective utilization of the novel elite wheat germplasm and improving the level of productivity that the genes mapping and genetic analysising for the related traits associated with the three yield components.The wheat-A. cristatum derivative 3228 was the progency of the cross between the common wheat Fukuho and the A. cristatum. It possesses the superior numbers of florets and grains. This special characteristic showed as its number of spikelets, florelets and grains per spike were 25, 6-8 and 90-100, respectively. In this study, the genetic analysis and QTL mapping of the superior grain number and the yield related traits were conducted for the wheat-A. cristatum 3228, and obtained the following results:1. The F2:3 population derived from the cross between the wheat-A. cristatum 3228 and Jing4839 was developed for the first time, and the inheritance analysis for the GNS,TGW,SNP, FPS and SL of the population were accomplished using mixed major gene plus polygenes inheritance model of quantitative traits. Results showed that GNS of the population was suited to the A-4 genetic model and mainly controlled by one major gene, the heritability value of the major gene was estimated as 27.81%. While the other yield traits including TGW, SNP, FPS and SL, were suited to B-1 genetic model and controlled by two major genes, respectively. The heritability of these major genes with the effect of additive-domiance-espatic were estimated as 73.89%, 61.86%, 23.45% and 99.47%, respectively. Moreover, all the yield traits of the F2:3 population performed well, which suggested it would have the high utility value in wheat breeding in the further.2. A total of 233 the polymorphic primers of SSR and EST-SSR were used to genotype the F2 population from the cross between the wheat-A. cristatum 3228 and Jing4839, 197 primers of which were used to constrct the linkage map. This genetic map, covering the genetic distance of 2304cM with an average primer interval of 16.6 cM, covered all the wheat chromrosomes except the chromosome 1D.3. Based on the constructed genetic map and the investigation of the yield traits from Beijing, Shanxi and Sichuan, QTL analysis of the mapping population for the yield traits including PH, ESN, SL, SNP, FNS, GNS, TGW, SSP and LSN were conducted. As a result, a total of 99 QTLs were detected. Of which, 37 QTLs were indentified for yield components, that including 9 QTLs for spike number, 14 QTLs for grains number per spike and 14 QTLs for thousand grains weight. The number of QTLs detected for spike traits was 48, which including the QTLs for spike length, spikelets number per spike and florelets number per spikelet. The remaining QTLs were for the yield-related traits, contains 8 QTLs for plant height, 3 QTLs for the first internode length below spike and 3 QTLs for seed set percentage.These QTLs distributed on all the wheat chromosomes except the chromosomes 2A, 2B, 1D and 5D.4. In this study, ten important chromosome regions were also found, which including the maker interval Xbarc1055-Xbarc37 on the chromosome 6A, Xbarc20-Xwmc238 on the chromosome 4B, Xgwm126-Xgwm291 on the chromosome 5A, Xbarc170-Xwmc707 and Xbarc1047-Xwmc718 on the chromosome 4A and Xbarc243-Xbarc59 on the chromosome 5B. The number of QTLs mapped in each chromosome region was over three and these QTLs also formed some important QTL-clusters.5. The distribution of QTLs on the chromosomes, homologous groups and genomes were different. The QTLs were detected on all the linkage groups except 2A, 2B and 5D, the number of QTLs on the linkage group 6A was most, and then were the linkages groups 4A, 4B and 7B. The number of QTLs on the four linkage groups was 55, which accounting for over half of the total QTLs. For the different homologous groups, the number of QTLs on the homogroups 6 and 4 were most, its number were 26, respectively, and also account for over half of the total QTLs. The difference also be found for the QTLs distribution on genomes. The most of QTLs were detected on A genome, while the major QTLs were mainly from B genome.6. In order to explore the genetic effect of the related yield traits of the wheat-A. cristatum 3228 in the background of the different wheat cultivars, 3228 was crossed with the five main wheat cultivars from huanghuai winter wheat areas and they were planted in Beijing, Yangling of Shannxi and Chendou of Sichuan. The results showed all the yield traits of the wheat-A. cristatum 3228 perform well in the different environments, especially to GNS, SNP and SL. The yield traits of the different F1 were also stable across all the environments. The wheat-A. cristatum 3228 has the siginifcant positive additive effect in GNS, SNP and SL, GNS also has the siginifcant positive dominance effect, which suggested the wheat-A. cristatum 3228 was the excellent wheat germplasm in greatly improving GNS, SNP and SL of wheat in the further. The inheritance analysis and QTL mapping of the main yield traits and the yield related traits were conducted for the wheat-A. cristatum derivative 3228, and the genetic effects of the yield related traits of 3228 in the background of the different wheat cultivars was also made, which would provided the important basis for the effective utilization of the wheat-A. cristatum derivative 3228 in the wheat breeding practice in the future. |
