Sources of resistance to late blight and southern bacterial wilt.

In testing for resistance to S.B.W. all the P. I. lines were inoculated in the seedling stage in the greenhouse; some 200 lines survived the inoculation. Seeds of these 200 lines were again planted and the plants were inoculated in the seedling stage; lines having 50% or more of their plants survive this inoculation were set in a field in which almost 100% of the check (uninoculated susceptible) plants became infected with S.B.W. Twenty-six of these P. I. lines had plants showing no external symptoms or internal discoloration and have been listed as possessing resistance.

Plants of all these lines were set at Transou, N. C. at an elevation of over 3000 feet. Normally tomatoes in this area are killed by Late Blight; this year was no exception - lines with little or no resistance were wiped out early in the season. Lines having plants that had little infection were classified as being resistant. There were only 28 of the 909 P. I. lines that were classified as possessing some resistance.

Lines resistant to Late Blight

    North                North               North 
  Carolina     P. I.   Carolina     P. I.  Carolina      P. I.
    line      Number     line      Number    line       Number
  ________   _______  __________  _______  __________  _______
  1950-8-1    91,913  1950-153-N  117,898  1950-351-N  127,809
      26-1    92,865       179-1  118,790       395-1  128,236
      30-1    95,584       227-N  123,538       432-N  128,277
      32-1    95,586       234-N  124,132       449-N  128,445
      84-N   110,597       251-N  126,408       521-N  128,990
      86-N   110,946       287-N  126,907       566-N  129,065
      96-N   114,038       294-N  126,914       755-N  146,129
      99-1   114,492       305-1  126,925       757-1  146,609
      99-N      "          330-N  126,951       767-1  158,168
     104-N   114,967       331-1  126,952

    North               North                North 
  Carolina     P. I.  Carolina      P. I.  Carolina      P. I.
    line      Number    line       Number    line       Number
  _________  _______  __________  _______  __________  _______
  1950-76-1  109,833  1950-126-3  115,218  1950-340-1  127,798
       91-1  112,2l5          -4     "          344-l  127,802
       97-1  114,490          -5     "          344-2  127,802
       97-2  114,490          -6     "          344-3  127,802
       98-1  114,491          -7     "          357-2  127,817
       98-2     "          137-1  115,951       358-1  127,818
      107-1  115,194       226-1  123,438          -2     "
      108-1  115,195       251-1  126,408       364-1  127,824
      112-1  115,200       283-1  126,820       400-1  128,241
      112-2  115,200       286-1  126,906       552-1  129,051
      120-1  115,210       290-1  126,910       557-1  129,056
      120-2     "          337-1  127,795          -2     "
      126-1  115,218       337-2  127,795       571-1  129,070
         -2     "          339-1  127,797