GENETIC DIVERSITY OF COTTON LEAFHOPPER POPULATIONS, AMRASCA BIGUTTULA BIGUTTULA (ISHIDA) IN MAJOR COTTON GROWING REGIONS OF SOUTH INDIAVIMALA, M. BHEEMANNA, RAJESH CHOWDARY AND SRINIVASA REDDYAbstract Among the sucking pests attacking cotton, leaf hoppers (Amrasca biguttula biguttula) are very important. Both nymphs and adults suck the sap from under surface of the leaf causing specking symptoms, crinkling, distortion of leaves and reddening all along the sides of leaves with downward curling. It is an important and key pest causingboth quantitative and qualitative losses on Bt cotton. Amplification of a fragment (~ 850 bp) of the mtCOIgene was achieved by the primer pair: MT10/C1-J-2195 (5´- TTGATTTTTTGGTCATCCAGAAGT-3´) and MT12/L2-N-3014 (5´- TCCAATGCACTAATCTGCCATATTA- 3´) obtained from the UBC Insect Mitochondrial DNA Primer Oligonucleotide Set. Taxonomic identification results revealed that composite sample of adult cotton leafhopper population collected from for different states viz., Maharashtra (Akola, Parbhani, Nanded), Karnataka (Raichur, Bijapur, Dharwad), Tamil Nadu (Coimbatore, Madurai, Aduturai) and Andhra Pradesh (Hyderabad, Vijayawada, West Godavari) was Amrasca biguttula biguttula (Ishida). Mitochondrial cytochrome oxidase subunitI (COI)gene fragment was amplified and sequenced from the cotton leafhoppers collected from four different states with twelve locations. Highest genetic variation (0.072) was found between populations of Akola and West Godavari followed by Aduturai and Dharwad (0.068); the genetic variation was nil between the populations collected from rest of the location. Sequence analysis and dendrogram showed high similarity among the leafhopper population of major cotton growing districts of Maharashtra, Tamil Nadu, Karnataka and Andhra Pradesh and there was not much genetic variation among the populations.
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