Screening of promising tomato genotypes and their progenies against bacterial wilt.

Rajput, J.C., Furor, P.A. and Gondhalekar, C.B. F-24 Shishir, University Quarters, Dapoli 415712, Dist: Ratnajiri (M.S. ) INDIA

Tomato cultivation was set back in the costal belt of Maharashtra State (India) due to severe incidence of bacterial wilt caused by Pseudomonas Solanacearum Smith. The losses due to this disease are so high that commercial tomato production is not economic. Most of the improved cultivars showed severe wilting within 60 days of planting (Hedayatullah and Shah 1941; and Anonymous, 1989). Unfortunately there is no effective chemical control measure for this disease. Under these circumstances, the only alternative is to breed variety resistant to bacterial wilt. Hence, the work was initiated to identify the sources of resistance for this disease at this center in 1989. More than 200 tomato genotypes along with segregating population received from AVRDC, Taiwan were evaluated against bacterial wilt. The promising plant types were selected, stabilized and evaluated for disease resistance and yield. Subsequently, the genotype Selection-2 was released in the name of 'Sonali' in 1986. However, this variety could not satisfy the consumer's requirements. In view of this, the further breeding programme was initiated to develop high yielding variety with desirable fruit quality and bacterial wilt resistance. For this, the parents namely Sonali, NTDR-1, BWR-1, BWR-5, CRA-66 Sel.A, LE-79 and EC-216418 were involved in the breeding programme. The F2 progenies of few selected F1's were grown in a wilt infestation plot. One hundred and fifty seedlings of each F2 progeny were transplanted at spacing of 60 x 60 cm. The seedlings of highly susceptible cultivar viz; Pusa Ruby were planted after every third row as susceptible check so as to test uniform spread of inoculum throughout the field. The mortality of the seedlings was recorded at an interval of 15 days from transplanting and continued up to 120 days. The disease intensity was graded as Immune (I), Resistant (R), Moderately Resistant (MR), Susceptible (S) and Highly susceptible (HS) with 01, 1 to 10, 11 to 20, 21 to 50 and 51 to 100 per cent mortality respectively.

Table 1. Reaction of different tomato genotypes and their F2 progenies against bacterial wilt

_______________________________________________________________________________
Parent/progeny              Per cent wilting after transplanting       Reaction
                       ________________________________________________
Parents               15   30     45     60     75     90    105    120
_______________________________________________________________________________
NTDR-1                 -    -  24.12  34.48    100    100    100    100     HS
BWR-1                  -    -   3.33   3.33   3.33   3.33   3.33   3.33      R
BRW-5                  -    -     -      -      -    7.86   7.86   7.86      R
LE-79                  -    -     -      -      -      -    6.66   6.66      R
Sonali                 -    -     -      -      -      -      -   10.00      R
Anahu                  -    -     -    6.66  13.33  13.33  23.33  56.66      S
Arka Vikas             -    -   3.44  41.37  55.17  55.17  55.17  55.17      S
CRA-66 Sel.A           -    -     -      -      -      -    3.21   3.21      R
EC-216418              -    -     -      -      -      -      -   10.00      R

F2 Progenies
_______________________________________________________________________________
BWR-1 x NTDR-1         -    -   0.92   3.70  14.81  14.81  26.85  26.85      S
LE-79 x Anahu          -    -     -      -    2.42   2.42   4.24   7.87      R
BWR-1 x Arka Vikas     -    -   0.65   4.87  12.80  12.80  29.26  29.26      S
BWR-5 x Arka Vikas     -    -   1.42   2.85  16.42  16.42  16.42  16.42     MR
BWR-1 x CRA-66 Sel.A   -    -     -      -      -      -    3.21   3.21      R
Sonali x EC-216418     -    -     -      -      -      -    2.00   2.00      R
BWR-5 x BWR 1          -    -     -      -      -      -    2.11   2.11      R 
BWR 5 x Anahu          -    -   5.82   5.82   5.82   5.82   5.82   5.82      R
Pusa Ruby              -    -    100    100    100    100    100    100     HS
(Susceptible Check)
_______________________________________________________________________________

**** The following note is a corrected reprint of the TGC-42 note which had
several unfortunate typographical errors.  - The editors apologize for any
inconvenience ****