Southern bacterial wilt is the most important disease of tomato in the warm humid tropics and acidic soils of Kerala (India). From 205 tomato lines screened in diseased fields, the line LE 79 (CL 32d-0-1-1-1-19GS) was the only one which withstood the disease. The original material of this line was introduced from AVRDC, Taiwan. The improvement achieved in this line is the increased fruit size. The plants are semi-determinate with medium-size green shouldered fruits with few seed cavities.
The line was put to test under multilocation trials and under laboratory conditions (Tables 1 and 2). The trials conclusively indicated the resistance of LE-79 to several isolates bacterial wilt. The stem inoculation trials using 11 virulent isolates of Pseudomonas solanacearum indicated that the line is resistant to isolates K 60, 126408-1 and Tifton 80-1.
Further studies on the genetic and biochemical bases of resistance of the line to bacterial wilt are in progress.
Table 1. Survival of LE 79 under multilocation testing.
_____________________________________________ Location Survival _____________________________________________ I (Vellanikkara, India) 80.16 II (Mannuthy, India) 94.00 III (Pattambi, India) 71.00 IV (Calicut, India) 40.00 V (Kottarakkara, India) 60.00 VI (Chalakudy, India) 55.90 VII (Nileshwar, India) 100.00 VIII (Bangalore, India) 100.00 _____________________________________________Table 2. Reactions of tomato lines to different isolates of Pseudomonas solanacearum.
_____________________________________________________ Material LE 79 Pusa Ruby Rutgers Venus Saturn _____________________________________________________ Pathogen isolates K 60 - + + + + W 82 + + + + + W 119 + + + NK NK W295 + + + + + PS2-2 + + + + + FF + + + + + A 21 + + + + + TFP 12 + + + + + TFP 13 + + + + + 126408-1 - + + - + Tifton 80-1 - + + + + _____________________________________________________ + Diseased; - Not diseased; NK not known.