Abstract:

Four mapping methods, the interval mapping(IM) , the composite interval mapping(CIM), the mixed composite interval mapping(MCIM) and the multiple interval mapping(MIM), were employed to detect the quantitative trait loci（QTL） of rice plant height with an F₂ data from the intercross PA64S×Nipponbare. The results are as follows: (1) 7 significant QTLs were detected by IM，10 QTLs by CIM，3 QTLs by MCIM，1 QTL by MIM for the trait at the same significant level. So CIM had the highest detective capability among the four methods. (2) The loci detected by IM were also detected by the method of CIM, and aiming at the same QTL, their distance to the left marker was almost coincidence.（3）Only a same QTL could be detected by all the four methods, respectively, and the locus had the biggest contribution to plant height. (4) The differences for average of additive effects (absolute values) or dominant effects(practical values) of QTLs were insignificant among four methods and the dominant effects of the same QTLs had the same direction. (5) The epistatic effects could be estimated by MCIM and MIM in the four mapping methods. Only MCIM was employed to estimate the epistatic effects under the significant level at 0.005 because only one QTL was detected by MIM in the paper. (6) A suggestion for mapping QTLs is that multiple methods should be considered, and it is preferential to declare the QTLs confirm simultaneously by the four methods.

Key words: QTL mapping, IM, CIM, MCIM, MIM