Subash Chandra Bose S
Screening And Biochemical Characterization Of Tomato Genotypes For Resistance To Bacterial Wilt - Vellanikkara Department of Olericulture, College of Horticulture 1999
Investigation on 'Screening and biochemical characterization of tomato
genotypes for resistance to bacterial' wilt' was carried out in the Department of
Olericulture, and Biochemistry Laboratory, College of Horticulture, Vellanikkara
1
during 1997-99. The objectives of this study were to identify tomato genotypes
resistant to bacterial wilt and to find the possibility for biochemical cataloguing of
bacterial wilt resistant tomato genotypes.
Evaluation for bacterial wilt resistance revealed that Sakthi, Mukthi and
LE-474 were consistently resistant to bacterial wilt. Four additional sources of
bacterial wilt resistance were identified, viz. LE-214, LE-415, LE-470 and LE-421.
Based on the percentage wilting the twenty four genotypes included in this study
were classified into four groups, viz. Resistant, Moderately Resistant, Susceptible
and Highly susceptible. -.:
All the bacterial wilt resistant and moderately resistant genotypes had a
higher content of total phenols in roots and leaves at 45th and 60th day of plant
growth;
O.D. phenol content in roots of resistant varieties were higher than
susceptible varieties. In leaf, the O.D. phenol content was high in moderately
resistant genotypes at 45th and 60th day.
All the genotypes were studied for isozyme variation with respect to two
enzymes, viz. polyphenol oxidase and peroxidase. 10 general the roots had more
number of bands compared to leaves at both the stages.
'.. The root samples at 45th day showed two polyphenol oxidase bands, viz.
PPO-I (~=0.074) and PPO-12 (Rm=0,414) which were specific to resistant
varieties alone. This combination along with high total phenols may be considered
as a biochemical marker for resistance to bacterial wilt in tomato. In 60 days old
-
roots of resistant and moderately re istant genotypes the protein band PPO-9
(Rm=0.851) was predominantly present
Regarding peroxidase, 45 . days old leaf samples had a combination of
protein bands, viz. PRX-7 (Rm=0.361) and PRX-8 (Rm=O.382) in resistant and
moderately resistant varieties. But at 60 days the roots and leaves did not show any
specific band for resistance.
In general at 45 days both leaf and root samples had more number of
bands for polyphenol oxidase and peroxidase in resistant varieties compared to
susceptible varieties. The study revealed that it was possible to arrive at a
combination of specific isozyme bands at a particular growth stage, which can be
used as a marker for bacterial wilt resistant tomato genotypes.
635.6 / SUB/SC
Screening And Biochemical Characterization Of Tomato Genotypes For Resistance To Bacterial Wilt - Vellanikkara Department of Olericulture, College of Horticulture 1999
Investigation on 'Screening and biochemical characterization of tomato
genotypes for resistance to bacterial' wilt' was carried out in the Department of
Olericulture, and Biochemistry Laboratory, College of Horticulture, Vellanikkara
1
during 1997-99. The objectives of this study were to identify tomato genotypes
resistant to bacterial wilt and to find the possibility for biochemical cataloguing of
bacterial wilt resistant tomato genotypes.
Evaluation for bacterial wilt resistance revealed that Sakthi, Mukthi and
LE-474 were consistently resistant to bacterial wilt. Four additional sources of
bacterial wilt resistance were identified, viz. LE-214, LE-415, LE-470 and LE-421.
Based on the percentage wilting the twenty four genotypes included in this study
were classified into four groups, viz. Resistant, Moderately Resistant, Susceptible
and Highly susceptible. -.:
All the bacterial wilt resistant and moderately resistant genotypes had a
higher content of total phenols in roots and leaves at 45th and 60th day of plant
growth;
O.D. phenol content in roots of resistant varieties were higher than
susceptible varieties. In leaf, the O.D. phenol content was high in moderately
resistant genotypes at 45th and 60th day.
All the genotypes were studied for isozyme variation with respect to two
enzymes, viz. polyphenol oxidase and peroxidase. 10 general the roots had more
number of bands compared to leaves at both the stages.
'.. The root samples at 45th day showed two polyphenol oxidase bands, viz.
PPO-I (~=0.074) and PPO-12 (Rm=0,414) which were specific to resistant
varieties alone. This combination along with high total phenols may be considered
as a biochemical marker for resistance to bacterial wilt in tomato. In 60 days old
-
roots of resistant and moderately re istant genotypes the protein band PPO-9
(Rm=0.851) was predominantly present
Regarding peroxidase, 45 . days old leaf samples had a combination of
protein bands, viz. PRX-7 (Rm=0.361) and PRX-8 (Rm=O.382) in resistant and
moderately resistant varieties. But at 60 days the roots and leaves did not show any
specific band for resistance.
In general at 45 days both leaf and root samples had more number of
bands for polyphenol oxidase and peroxidase in resistant varieties compared to
susceptible varieties. The study revealed that it was possible to arrive at a
combination of specific isozyme bands at a particular growth stage, which can be
used as a marker for bacterial wilt resistant tomato genotypes.
635.6 / SUB/SC