302 V. Selvanarayanan
concentrations (Table 13 ). In the M1 genera-
tion, plants of Varushanadu Local mutagenized
with DES @ 0.2 % recorded the least popula-
tion of whitefly whereas in M2 and M3 genera-
tion, plants mutagenized with EMS @ 0.3 % and
Gamma rays @ 5 KR recorded the least popula-
tion of whitefly. Though whitefly population was
noticed, symptoms of leaf curl disease could not
be observed in all the three generation suggest-
ing that the population present may not be active
transmitters (Gopalakrishnan 2010 ).
Inherent Insect Resistance Vis-A-Vis
Induced Insect Resistance in Tomato
In view of the failure of conventional hybridiza-
tion in exploiting the inherent resistance in the
selected accessions, inducing insect resistance
using external inputs was attempted. Arbuscular
mycorrhizal fungi (AMF), which form symbiotic
associations with root systems of most agricul-
tural, horticultural and hardwood crop species,
have been suggested as widespread potential bio-
protective agents. Fungal symbiosis in various
crop plants confers tolerance and/or resistance
against many phytophagous insects, nematodes
and pathogens. Co-inoculation of AM fungus,
Glomus spp. with Azospirillum brasilense (Linn.)
reduced the incidence of leaf folder, Cnaphalo-
crocis medinalis Guen. in upland paddy var.
PKM−1 (Amutha et al. 2003 ) while individual
inoculation of G. intraradices in pea plants con-
ferred resistance against the adult weevils, Sitona
lineatus (Wamberg et al. 2003 ). In view of the
above, the influence of AM fungal inoculation in
inducing resistance in the selected tomato acces-
sions against fruit worm, H. armigera and leaf
caterpillar, S. litura was analysed. The resistant
tomato accession namely Varushanadu Local
and the susceptible check, I 979 identified ear-
lier were tested for their interaction with four AM
fungi viz., Glomus fasciculatum (Thaxt.)Gerd.
and Trappe, Glomus mosseae (Nicol. and Gerd.),
Acaulospora laevis (Gerd. and Trappe) and Gi-
gaspora margarita (Becker and Hall) under pot
culture conditions and also under field conditions
for two seasons (Gopalakrishnan 2006 ).
The length of the trichomes on tomato foli-
age was found increased, but their density was
not enhanced considerably in AM fungal inocu-
lated plants. On analyzing the phenol content of
the leaves of the test accessions, it was found
that G. margarita inoculated plants of the re-
sistant accession Varushanadu Local contained
higher amount (0.3303 mg/g of leaf) followed by
G. mosseae, G. fasciculatum, A. laevis (0.3106,
0.3105, 0.3022 mg/g respectively) as against the
least in control plants (0.3007 mg/g). Based on
the above, it is inferred that the role of ArbuscularTable 13 Field evaluation of tomato mutant generations against B. tabaci
Mutagen Population of nymphs per plant
M1 M2 M3
Conc VL I 979 VL I 979 VL I 979
DES
0.09 % 20.78 30.39 21.39 25.94 14.56 17.94
0.1 % 19.39 29.28 14.94 21.88 12.22 15.00
0.2 % 18.38 26.83 14.33 21.72 10.56 13.06
EMS
0.2 % 19.72 27.78 13.11 19.55 11.39 14.39
0.3 % 20.72 27.05 14.89 21.28 10.98 14.83
0.4 % 23.50 30.33 16.83 23.38 13.89 17.67
Gamma rays
5 KR 19.88 29.33 16.94 23.67 13.28 17.34
10 KR 20.83 28.61 16.00 22.61 13.11 17.67
15 KR 17.94 30.22 14.98 22.27 11.78 15.22
Control 31.22 38.45 31.33 42.89 22.34 28.22
C.D. ( p = 0.05) 2.33 3.10 2.1 1