IDENTIFICATION AND EVALUATION OF TURNIP MOSAIC-VIRUS (TUMV) RESISTANCE GENE IN KALE MONOSOMIC ADDITION LINES OF RADISH

TuMV resistance in seven types of monosomic addition lines of radish w ith kale chromosomes (a similar to g types, 2n=19, B-5) was surveyed b y scoring the symptoms after the mechanical inoculation, The level of the resistance was also evaluated by ELISA in five f-type addition lin es (B-7, B-8, B1F1 and B2F1) obtained by crossing f-type plants (2n=19 , B-5) with five radish cultivars, Among the seven types of monosomic addition lines, the f-type line rarely showed detectable symptoms, The scores of the symptoms were 0.1 in f-type line, 1.6 to 2.7 in the rev ertants (2n=18) and 2.4 in the radish cultivar 'Shogoin', respectively , The f-type plants in the subsequent generation (B-6) derived from th e f-type addition lines by backcrossing with the radish cultivar 'Shog oin' gave a score close to that of the f-type plants (B-5) These resul ts suggest that the gene (s) for TuMV resistance may be located on the added f-chromosome of kale and that this trait was transmitted domina ntly to the next generation along with the transmission of the f-chrom osome. ELISA value in the youngest leaves of five f-type lines (2n=19, B-7 and B1F1) derived from the crossing between the f-type line (B-5) and five cultivars of Japanese radish was remarkably low (Av, 0.154) three weeks after inoculation, The values of the revertants (2n=18) an d five radish cultivars were 1.259 and 0.774 on the average, respectiv ely. The ELISA values were also low in the sequentially growing leaves from the youngest leaves to the older ones in all the f-type lines ni ne weeks after inoculation. The symptoms and ELISA values in the young est leaf of the five f-type progenies (2n=19, B-8 and B2F1) were simil ar to those of the maternal f-type plants, where ring spot symptoms we re sometimes observed only in the leaf immediately above the inoculate d one in four f-type lines. ELISA value in the leaves immediately abov e the inoculated ones was somewhat higher in a few plants of all the f -type lines than the youngest leaves, Based on these results, the mech anism of TuMV resistance in the f-type lines was attributed to the low level of propagation and inactive transfer of TuMV.