Abstract
Problem statement: Whitefly, Bemisia tabaci is an important sucking
pest of field, horticultural and ornamental plants causing feeding injuries besides
spreading disease by acting as a vector of Gemini viruses. The polyphagous nature
of the pest makes it as a highly complex species. Approach: The
influence of host plants utilized by the species on the population differences
at molecular level was attempted using Random Amplified Polymorphic DNA (RAPD)
markers. Results: Ten RAPD primers out of the total seventeen
primers screened produced 236 markers. The total number of bands obtained from
each primer ranged from 11-35 with an average of 23.60 bands per primer. Of the
pair wise combination among thirteen species, Srivilliputhur population showed
the highest similarity index (0.826) while the lowest (0.111) was recorded by
Namakkal population. The similarity coefficient based on the 236 RAPD markers
generated ranged from 0.111-0.826. Three major clusters were formed from UPGMA
dendrogram, which was constructed based on Jaccard’s similarity. PCR screening
demarcated the whitefly population based on the host species. The first cluster
included population collected from okra and cotton, while second cluster comprised
of population from eggplant and cauliflower and the third cluster included population
from eggplant. It could be deduced that population from cotton and okra had 50%
similarity, while 60-70% similarity was observed for population from eggplant
and cauliflower. Conclusion: Our investigation offered the lead
that within a narrow geographical region there exits variation based on host plants
being utilized by the whitefly population.