Analysis QTL And Its Distribution Characteristics Of Heading Date And Plant Height In A Population Of Multi-genotype Breeding Of Rice

Heading date and plant height are important agronomic traits of rice.Manylinkage maps at high density of molecular markers have ever been constructed forthese two quantitative traits. In this study, Ninety-five SSR markers of rice wereadapted to detect the quantitative traits of heading date and plant height of 11 parentallines and 214 stable fundamental populations of multi-genotype breeding which werecreated by piled-up hybridization. Field experiments of the stable populations derivedfrom 11 parental lines were conducted in Guangzhou in the years of 2002,2004,2006.The agronomic traits investigated included heading date and plant height. Analysis ofquantitative trait locus with SSR marker was carried out against these two traits.The frequency distribution of heading date and plant height in the stablefundamental populations of multi-genotype breeding of the three years displayed anunderlying bimodal distribution and showed transgressive segregation.The results su-ggested that these two traits were controlled by the major and minor QTLs.A total of 95 SSR markers were employed to identify QTLs which associate withheading date and plant height. Based on ANOVA and correlation coefficient analysis(P＜0.01),20 putative QTLs which controll the heading date of 2004 and 2006 weredetected. These putative QTLs were located on chromosomes 1,2,3,4,5,6,7,8,9,11,12respectively. The percentage of phenotypic variations explained by these QTLs rangedfrom 3.36% to 22.89%. Based on ANOVA and correlation coefficient analysis(P＜0.01),6 putative QTLs associate with plant height were found to be located onchromosomes 1,2, 5,8 respectively. The percentage of phenotypic variations in plantheight explained by these QTLs ranged from 2.60% to 10.7%.12 QTLs which controllthe heading date have ever been free mapped for in their linkages, qDTH-1 onChromosome 1,Hd-6 and Hd-9 on the Chromosome 3, Hd-11 on the Chromosome 4,qDTH-5 on Chromosome 5,Hd-1 and Hd-3 on the Chromosome 6,Hd-2 and Hd-4 onthe Chromosome 7,Hd-5 on the Chromosome 8, qDTH-9 on Chromosome 9,Hd-13 onthe Chromsome 12. Among the 6 QTLs associate with plant height which weredetected in the experiment 5 of them including PTHT1, ph2.1, ph5.1, PTHT8, ph8.1located on Chromosome 1,2,5,8 respectively. The pattern of permutation and combination between the genotype of markers andphenotype of traits (including heading date and plant height) were analyzed.A total of184 patterns were detected by 10 SSR markers which associate with the heading datein the year of 2004.And a total of 118 patterns were detected by 6 SSR markers whichassociat with the heading date in the late cropping season of 2006.For plant-heightassociated markers,a total of 151 patterns were discovered.The result indicates thatplants with identical or similar phenotype but with different genotype can be selectedfrom the stable fundamental populations of multi-genotype breeding.