Resistance of lines from three-genome hybrid (Lycopersicon esculentum Mill. - L. chilense Dun. - L. peruvianum Var. humifusum Mill) to Pseudomonas syringae pv. tomato

Sotirova, V., Bogatzevska, N. Institute of Genetics, Sofia - 1113, Bulgaria

Bacterial speck of tomato caused by Pseudomonas syrangae pv. tomato (Okabe) Young et al. has become a serious problem in many tomato production areas (Goode and Sasser, 1980; Bogatsevska, 1988). The efforts of selection on world scale are directed towards creating varieties resistant to the agent of this disease.

A series of backcrosses of plant from three-genome hybrid with L. esculentum resulted in development of lines with a valuable biological and economic characters. These lines were tested for resistance to race 0 and race 1 of P.s.t. The plants were inoculated by vacuum infiltration method in the phase 4-5 true leaves with race 0 and race 1 of P.s.t. (Sotirova, Bogatsevska, 1990). The evaluation of disease severity was made by Chambers' and Merriman's scale (1975).

The data obtained from the inoculation of lines from three genome hybrid with race 0 and race 1 of P.s.t. are presented in Table 1. Some lines are distinguished on degree of resistance to race 0 and race 1. The lines LCH 36, LCH 47, LCH 165, LCH 168 are resistant to race 0, but are susceptible to race 1. One line LCH 54 is resistant to race 1. The lines LCH 50, LCH 166, LCH 167 and LCH 177 are resistant to both of races. These lines are distinguished by abundant pollen production and high percentage of fruit set unfavorable climate conditions. Both of lines LCH 50 and LCH 177 are distinguished by large fruits with excellent favor.

The lines with resistance either to race 0 or either to race 1 deserve attention, but the lines possessing resistance to both races are especially valuable. These lines could be used in selection program for creating tomato varieties resistant to P.s. pv. tomato.

Table 1. Resistance of lines from three genome hybrid (L. esculentum -L. chilense -L. peruvianum var. humifusum) to race 0 and race 1 of P.s.t.

______________________________________________________________________________
Lines                   Race 0                            Race 1
      _________________________________   _____________________________________
      Total # of  # of    mean   Av. # of Total #    # of   mean    Av. # of
        Plants   healthy  score spots per of plants healthy score  spots per
                 plants           plant              plants          plant 
_______________________________________________________________________________
LCH 36    25       25     0.0      0          25        10      1.0      5 
LCH 44    25       25     2.8     18          25         5      2.2     21 
LCH 47    25       20     0.6      6          25         -      3.6     45
LCH 48    25        5     2.9     12          25         3      3.2     34 
LCH 49    25       12     1.4     13          25        10      1.1     15 
LCH 50    25       25     0.0      0          25        25      0.0      0 
LCH 54    25       22     0.5      3          25        25        0      0 
LCH 58    25        -     3.5     32          25         -      3.8     40 
LCH 60    25        4     2.2     24          25         2      2.5     41 
LCH 62    25        -     4.0     59          25         -      3.6     47 
LCH 90    25        5     2.6     22          25         -      3.1     32 
LCH 91    25       10     2.0     23          25         -      4.0     52 
LCH 93    25       12     1.0     12          25        10      2.1     32 
LCH 94    25       10     1.5     10          25        12      2.3     18 
LCH 101   25        -     1.0     43          25         -      2.6     39 
LCH 108   25        -     1.3     30          25         -      2.8     29 
LCH 161   25        -     1.9     16          25         -      2.0     18 
LCH 163   25        3     1.7     14          25         -      1.9     15 
LCH 164   25        7     1.4     13          25         -      2.3     20
LCH 165   25       25     0.0      0          25        21      0.5      3 
LCH 166   25       25     0.0      0          25        25      0.0      0 
LCH 167   25       25     0.0      0          25        25      0.0      0 
LCH 168   25       25     0.0      0          25        20      0.5      3 
LCH 172   25       25     0.0      0          25         -      2.2     20 
LCH 177   25       25     0.0      0          25        25      0.0      0 
Ontario   25       25     0.0      0          25        20      1.0     15
7710
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Literature cited

Bogatsevska, N. 1988. Plant Science
Good, M.M. and Sasser, M. 1980. Plant Dis. 64:831-834.
Sotirova, V., N. Bogatsevska. 1990. Comptes rendus de l'Academie bulgare des Sciences, T. 43, No. 2, 89-91.