Vol. 10, Special Issue 9 (2021)

Author(s):
MK Ponselvakumari, M Murugan, C Chinniah, G Karthikeyan, J Ramalingam and A Beaulah

Abstract:
Whitefly, Bemisia tabaci is one of the major constraints for tomato production worldwide both by direct damage of desapping the plant phloem content and indirectly by transmitting plant viruses especially begomoviruses. Vectoring capability of B. tabaci vary widely all over the Indian sub-continent. Exploration of resistant tomato genotypes is very much important for the effective and environmentally safer management of whitefly and its spread of tomato leaf curl virus (ToLCV) on tomato. Among the three plant resistance mechanisms, presence of non-preference (Antixenosis) mechanism is crucial in checking virus spread for certain plant viruses like ToLCV, which will limit the selection of host plants for feeding and oviposition by the vector insects. Selected tomato which performed better from field and glasshouse screening experiments were evaluated in laboratory condition for its antixenotic fitness by conducting leaf surface test for egg laying preference, trichome density and wax concentration test. The genotypes EC-631364 (4.67 and 5.33), EC-620389 (5.67 and 3.33), EC-520078 (4.67 and 2.33) and EC-315477 (9.33 and 2.33) notably had the lowest mean number of B. tabaci eggs in the abaxial surface and abaxial surface of leaves. The highest mean number of eggs on both abaxial and abaxial surface of tomato leaves was observed to be in EC-620370, EC-620372, EC-538153 and EC-620427. Comparatively the preference for egg laying was more in the abaxial surface of the test genotypes held. The genotype EC-520078 recorded the lowest number of trichomes (114/cm²) followed by EC-620389 (125.33/cm²) and PKM1 (150/cm²). The highest content of epicuticular wax was observed in genotypes viz., EC-520078 (64.2 mg), EC-620389 (56.9 mg) and EC-315477 (48.1 mg), while it was the least on the genotypes EC-620372 (2.7 mg) and EC-620417 (10.57 mg). Overall, the genotypes viz., EC-520078, EC-631364, EC-315477 and EC-620389 were noted as highly resistant against whitefly with non-preference plant resistance mechanism and may need additional laboratory studies before making incorporation into resistance breeding strategies for B. tabaci and their vectoring capabilities of ToLCV on tomato.