2002 年 52 巻 4 号 p. 253-257
The suitability of background selection using DNA markers was assessed in a tobacco backcross breeding program for introgression of a potato virus Y (PVY) resistance gene (va/va) derived from a novel resistant source, Kerti No. 1, into the genome background of a commercial variety, Coker319. Ten randomly amplified polymorphic DNA (RAPD) and 76 amplified fragment length polymorphic (AFLP) markers specific to the Kerti No. 1 genome background (background markers) were identified based on the polymorphism analysis with Coker319 and they were used for background selection at loci not linked to va. Two markers flanking va on each side (linkage markers) were used for background selection of the va-carrying chromosome. In each backcross generation, 200 plants were developed and surveyed with only the background markers, while 300 plants were similarly treated with both the background and linkage markers in the BC3S 1 generation. One plant, where all the 86 randomly extracted background marker loci and 2 linkage marker loci were recovered in the recipient genotype, was obtained through only 3 backcrossings and 1 selfing. CKM1 (BC3S2) derived from this BC3S1 plant did not display any significant differences from Coker319 in terms of characters (e.g., yield, number of leaves, length and width of leaves, leaf-color change during the maturation period, yellowing rate in the curing process). In addition, CKM1 was similar to Coker319 in terms of aroma, taste and low smoke quality. These results demonstrated that the genomic background of CKM1 was almost identical with that of Coker319 and that background selection on both a carrier and noncarrier chromosome(s) by DNA markers significantly accelerated the progress of a backcross program in tobacco. CKM1 did not display any adverse effects on the line introgressing the PVY resistance derived from other sources. Therefore, Kerti No. 1 appears to be the most suitable source of PVY resistance for tobacco breeding programs.
