Mating compatibility, life-history traits, and RAPD-PCR variation in Bemisia tabaci associated with the cassava mosaic disease pandemic in East Africa

Maruthi, M.N., Colvin, John and Seal, Susan (2001) Mating compatibility, life-history traits, and RAPD-PCR variation in Bemisia tabaci associated with the cassava mosaic disease pandemic in East Africa. Entomologia Experimentalis et Applicata, 99 (1). pp. 13-23. ISSN 0013-8703

Abstract

The pandemic of a severe form of cassava mosaic virus disease (CMVD) in East Africa is associated with abnormally
high numbers of its whitefly vector, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). To determine
whether a novel B. tabaci biotype was associated with the CMVD pandemic, reproductive compatibility, fecundity,
nymphal development, and random amplified polymorphic DNA (RAPD) variability were examined in, and
between, B. tabaci colonies collected from within the CMVD pandemic and non-pandemic zone in Uganda. In
a series of reciprocal crosses carried out over two generations among the six CMVD pandemic and four nonpandemic
zone cassava B. tabaci colonies, there was no evidence of mating incompatibility. All the crosses
produced both female and male progeny in the F1 and F2 generations, which in a haplo-diploid species such
as B. tabaci indicates successful mating. There also were no significant differences between the sex ratios for the
pooled data of experimental crosses, between individuals from two different colonies and control crosses between
individuals from the same colony. Only one instance of mating incompatibility occurred in a control cross between
cassava B. tabaci from Uganda and cotton B. tabaci from India. Measures of fecundity of the pandemic and nonpandemic
zone B. tabaci on four cassava varieties showed no significant differences in their fecundity, nymphal
development or numbers surviving to adult eclosion. Cluster analysis of 26 RAPD bands using six 10-mer primers
was concordantwith the mating results, grouping the pandemic and non-pandemic zone colonies into a single large
group, also including a B. tabaci colony collected from cassava in Tanzania. These results suggest that it is unlikely
that the severe CMVD pandemic in East Africa is associated with a novel and reproductively isolated B. tabaci
biotype.

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