Bull. Spec. CORESTA Congress, Harare 1994, p. 129, PPOST 1

Resistance to four diseases in tobacco somaclones NC89-TT and NC89-V1 regenerated from toxin-stressed tissue culture of cv. NC89, and unstressed tissue culture of its resistant derivative

Shandong Agricultural University, Dept. of Plant Protection, Taian, Shandong, China
Tobacco somaclone NC89-TT was obtained from the flue-cured cv. NC89 from tissue culture challenged by AT-toxin of brown spot pathogen Alternaria alternata, and somaclone NC89-V1 was obtained from tissue cultures of plants previously inoculated with hypovirulent strain N14 of ToMV (tomato mosaic virus) which had been shown to be the best inducer of virus resistance in tobacco. The two clones were tested for resistance to brown spot (BS), wildfire (WF), black lowering (BL), and black shank (BSh). Frequencies of resistant regenerated tobacco showed the same model of gradual decrease from the first to the second selfed progenies in BS and BL, and showed an inverse model of gradual increase in WF and BSh. Degree of resistance of the second selfed progenies of the two somaclones were tested and compared with the parent NC89. The NC89-TT progeny had increased resistance at 92,2% to BS, 44,4% to WF, 43,8% to BSh, and 43,3% to BL. The NC89-V1 progenies had enhanced resistance at 80,7% to BS, 77,8% to WF, 68,8% to BSh, and 40,0% to BL. The reasons and potential application of the multiple-induced resistance are suggested.