The middle early tomatoes in Bulgaria were completely destroyed by CMV in 1986 and 1989. Up to now no resistant varieties are available and what is more the sources of resistance are very limited. Some tolerance to CMV is found in S. lycopersicoides (Phills et al., 1977; Laterrot, 1979) and in L. peruvianum (Laterrot, 1979; Ciccarese, 1987).
In 1988 we tested five L. peruvianum numbers and one L. hirsutum offered by P. Lindhout and two of our cultivated lines derived from crosses with L. chilense. High level of resistance was found in L. peruvianum LA 2388G 1567 having only one susceptible plant out of 12 plants inoculated with CMV field cucumbers. One of our lines - 5351/86, showed also resistance. We didn't detect any symptoms on the plants till the end of the vegetation.
The next year ten new numbers from our breeding material were tested using different CMV-isolates-from field tomato, field and green house cucumbers and from Hungary, the last one being the most pathogenic. All tested lines segregated for resistance and the ratio resistant: susceptible plants differ in every line depending on the CMV-isolates. Lines 5352/86, 5362/86 and 5363/86 showed the best results with fur CMV-isolates. They had 15 resistant out of 20 inoculated plants. The plants selected for future breeding program remained healthy and showed normal fruit setting. The fruits are round with middle size.
According to our information this is the first report on resistance to CMV found in cultivated breeding lines derived from crosses with L. chilense. The genetics of the resistance to CMV found in above mentioned lines is under investigation.
Literature cited:
Ciccarese, F., et al. 1987 Synopses of X Eucarpia tom. meet., Sa. Italy.
Laterrot, H. 1979 Sta. d'Amel. Pl. Maraich., Rapport d'activite, 110-112
Phills, B.R. et al. 1977 Tomato Genetics Cooperative Report, 27: 18.