Abstract:
The relative resistance/susceptibility of 45 varieties and 40 strains of upland cotton to cotton leaf curl virus
(CLCuV) was evaluated under field conditions at Punjab Seed Corporation, Khanewal. Two varieties
(CIM-446 & FH-901) and thirteen strains (FH-900S, CIM-473, CM-28,565/98,642/98,726/98, BH-549/99,
BH-147, BE-148, VH-137, Z-113, P-6 & P-8) were field immune while twenty two varieties (124F, 199F,
149F, B-557, MNH-93, MS-84, NIAB-78, CIM-70, FH-87, S-12, GOHAR-87, CIM-109, RH-1, NIAB-86,
MNH-329, MNH-147, BH-36, FH-682, S-14, SLS-1, Mixture and Karishma) and two strains (MNH-633 &
NIAB Karishma) were found to be highly susceptible. Graft inoculation studies of ten varieties and five
strains showed that none of the material was immune or highly resistant. Two varieties (NIAB-78 Sl NIABKarishma)
showed highly susceptible response and showed disease symptoms after 16 and 15 days of
grafting, respectively. Remaining varieties /strains were resistant or moderately resistant. Only two
varieties (FH-900 & FH-901) and two strains (NIAB-98 & FH-945) resist more as they delayed disease
appearance after grafting till 22,22,23 & 22 days respectively. Graft inoculation studies showed difficulty
of obtaining highly resistant source, so the preference should be given to the germpfiasm which resist more
against CLCuV and meanwhile search for immune source should be continued. It is also suggested that
strains showing “field immune” or “highly resistant” response to virus infection in a field and other
desirable agronomic characters may be recommended for high cotton yield.
