The paper describes the following problems: the spread and the economic effect of tomato bacterioses in the world and in Yugoslavia caused by Pseudomonas tomato (Okabe) Alstutt, Xanthomonas vesicatoria (Doidge) Dowson, X. gardneri Sutic, Pseudomonas solanacearum (F.F.Smith) and Corynebacterium michiganeuse (E.F.Smith); symptoms of diseases, isolation and pathogenic testing; cultivating, morphological and biochemical characteristics of the investigated isolates; the physiological specialisation of parasites; epidemiology; the sensitivity of tomato varieties to Pseudomonas tomato; the influence of P. tomato on tomato yields in the conditions of spontaneous infection; and the possibility of P. tomato chemical control.

The paper describes the following problems: the spread and the economic effect of tomato bacterioses in the world and in Yugoslavia caused by Pseudomonas tomato (Okabe) Alstutt, Xanthomonas vesicatoria (Doidge) Dowson, X. gardneri Sutic, Pseudomonas solanacearum (F.F.Smith) and Corynebacterium michiganeuse (E.F.Smith); symptoms of diseases, isolation and pathogenic testing; cultivating, morphological and biochemical characteristics of the investigated isolates; the physiological specialisation of parasites; epidemiology; the sensitivity of tomato varieties to Pseudomonas tomato; the influence of P. tomato on tomato yields in the conditions of spontaneous infection; and the possibility of P. tomato chemical control.

Inheritance of resistance to C. coccodes and C. dematium was compared using a 6-parent diallel in 1982. The parents, one set of F1 hybrids and 5 reciprocal crosses were grown at Beltsville and harvested fruits were inoculated hypodermically with spore suspensions of each spp. Reciprocal effects were not present in either set of inoculations of the 2 pathogens for the 5 crosses studied. Mean squares for general combining ability accounted for most of the genetic variability in both sets of inoculations. Mean squares for specific combining ability were only significant for C. dematium inoculations. According to the analysis of variance and covariance of the parental arrays, partial dominance appeared to be in the direction of susceptibility. Narrow-sense heritabilities were 78% for C. coccodes and 64% for C. dematium. The correlation coefficient between inoculations with C. coccodes and C. dematium was 0.87.

In investigations on the effect of virus infection on the tomatine content in tomato leaves the age at which the leaves show the highest tomatine level was at first determined. Systemic infection of tomato plants, caused by CMV, induced a decrease in the concentration of tomatine, manifecting itself in attenuation of the rabbit erythrocyte hemolysis ability of this sap. A similar effect of reduction of the active substance level in plants is exerted by mycoplasma-type organisms