| Many important agronomic traits are quantitative in nature. It is very important to accurately identify and finely map quantitative trait loci (QTL). In our experiment, a series of single segment substitution lines (SSSLs) in an elite inbred line 87-1 genetic background of maize was developed. Using linkage analysis based on advanceed backcrosse population, a new resistance gene scm3 resistanted to the Sugar Cane Mosaic Virus (SCMV) derived from an elite inbred line Hai9-21was identifid. The main results are as follows:1. A series of chromosome single segment substitution lines was developed, included 26 homogeneous SSSLs and 58 heterogous SSSLs. In the 26 SSSLs, the average substituted segment length was 24.97cM; the total length was 649. 1cM, with coverage of 15.7% of maize genome. In the 58 heterozygosity SSSLs, the average substituted segment length was 24.26cM and the total length was 1407.4cM, with a coverage of 31.24% of entire maize genome. In the 84 SSSLs, the donor segment length is 2056.45 cM in total, the coverage was 32.75 % of maize genome.2. Three genomic parameters were analyzed in the developing process of SSSLs. From BC2F1 to BC4F1, the donor segment number, the donor segment length and the donor genome size reduced 58.92%, 23.19%, 68.48% respectively. From BC4F1 to BC5F1, the donor segment number, the donor segment length and the donor genome size reduced 42.00%, 28.82% and 59.97%, respectively.3. Bulked segregate and microsatellite analysis of a BC2F3 progeny derived from Ye478×Hai9-21 were used to identify the resistance gene to sugar cane mosaic virus, scm3, a new resisitant gene to SCMV was mapped on the short arm of chromosome 3, near the centromere. scm3 was tightly linked to the microsatellite marker, bnlg420. The linkage distances between umc2265 - scm3 and scm3- bnlg420 are 46.5 centiMorgan (cM) and 5.9cM respectively.
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