| A population of recombinant inbred lines(RIiLs) derived from an elite hybrid, Shanyou 63, was grown in 1999&2000 to measure the quantitative traits,i.e. heading time (HT), plant height (PH), panicle length (PL), 1000-grain weight (KGW), seed setting (SS), grain number per panicle (GNP) and spikelets number per panicle (SNP). A molecular linkage map comprising 221 markers was applied to locate QTL for these agronomic traits, using the method of least-squares-based composite interval mapping. The main results are summarized as follows:1. All examined traits displayed continued variation and approximately normal distribution, indicating that all of these traits were quantitatively inherited. ANOVA showed that there were significant genotypic difference between R1Ls. It also revealed that there were significant differences between the two years for all traits with the exception for GNP and interaction effects between genotype and environment were significant.2.Total 23 QTLs were mapped in the joint QTL analysis of the two years.I )One QTL for HT was detected on chromosome 11 , which could determine HT for about 1?d.2)Five QTLs for PH were detected on chromosome 3, 5, 9 and 12. Among them , htl2a and htl2b were located on chromosome 12 and these two QTLs had opposite effect. The QTL in the marker interval C732桼2672 of chromosome 12 had the largest effect ,which could underly PH about 2.3cm and explained 4.85% of the total phenotypic variance in 2000.3)Seven QTLs for PL were detected on chromosome 1, 2, 7, 9, 10 and11 .Among them two were mapped on chromosome 2. All these QTL had small additive effect ranging from 0.2 1cm to 0.53cm.4)Four QTLs for KGW were detected on chromosome 5, 6, 9 and11 .These QTLs had similar additive effects with range from 0.54g to 0.87g.5)Three QTLs for SS were detected on chromosome 10, 11 and 12 respectively, explaining 21.06% of the total phenotypic variance in 1999 and 16.41% in 2000 ,respectively.6)Two QTLs for GNP were detected on chromosome 5 and ii. The QTL on chromosome 11 had a larger effect, which could explain 13.5% of the total phenotypic variance in 1999 and 14.9% in 2000 respectively.7)Only I QTL for SN? was detected on chromosome 6. Its additive effect was larger in 2000 than in 1999. In 2000, It could determine SN? for about 8 grains and explained 6.38% of the total phenotypic variance.3. The two years data were analysised separately. Twelve QTLs were discovered including 1 for HT, 4 for PL, 1 for 55 and 2 for GNP in 1999&eighteen QTLs including 5 for PH, 5 for PL, 3 for KGW, 2 for GNP and I for SN? in 2000.The number of the same QTL detected in the joint analyses and separated analysis for two years was 2 for PL(pl2b and p17), 2 for KGW (kgw6 and kgw9)and I for GNP(gnpll).These 5 QTLs are stable in the two years,while the others are sensitive to environmentsin conclusion,the joint analysis were sensitive in QTL detection than the separated analysis.4. Both the interval between marker RM26 and C 1447 in chromosome 5 and the region near the marker C794 exists QTLs that effect GNP and KGW, and the QTLs for two traits had opposite effect that could explained the negative phenotypic correlationship. The two QTLs, gnp9 and kgw9 with the same effects direction, were located in the same interval between marker C 1232 and C732. It抯 usefiul for rice breeding programe. The region near the marker RG236 could affect both SN? and PL.In the last of the paper, the QTL number, the QTLx environment interaction, the distribution of QTL and the relationship between pleiotrphism and close linkage of different QTLs were discussed. |
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