A differential interaction study of Bemisia tabaci Q-biotype on commercialtomato varieties with or without the Mi resistance gene, and comparative host responses with the B-biotype
G. Nombela et al., A differential interaction study of Bemisia tabaci Q-biotype on commercialtomato varieties with or without the Mi resistance gene, and comparative host responses with the B-biotype, ENT EXP APP, 98(3), 2001, pp. 339-344
Three tomato varieties (Motelle, Ronita, and VFN8) bearing the Mi-1.2 gene
providing resistance to nematodes Meloidogyne spp. and to the potato aphid
Macrosiphum euphorbiae Thomas, and three varieties not bearing this gene (M
oneymaker, Roma, and Rio Fuego), were compared by choice assay for host pre
ference using the Q-biotype of Bemisia tabaci (Gennadius). The most preferr
ed hosts, determined by infestation levels and numbers of feeding adults we
re Moneymaker, Rio Fuego and Roma, all of which were not carrying the Mi ge
ne. Ronita and Motelle, both of which bore the Mi gene, were the least pref
erred hosts. In a no-choice assay, B. tabaci females laid a significantly l
ower number of eggs on the varieties that carried the Mi gene than on those
lacking the gene. Differences were more dramatic when plants carrying the
Mi gene were pooled together and compared with pooled plants without this g
ene. Significantly greater values were obtained for the Mi-lacking group fo
r all parameters tested. Comparing these results with those from a previous
study on the B-biotype of B. tabaci, Q-biotypes were found to produce high
er daily infestation rates on most of the tomato varieties. When results fr
om plants carrying Mi were pooled, they showed lower infestation levels of
Q-biotypes than B-biotypes. The Q-biotype infested less Mi-plants and more
non-Mi plants than B-biotype. Q-biotype females produced significantly less
pupae than the B-biotype females on both groups of plants. These results s
uggest the existence of an antixenosis and antibiosis-based resistance to t
he Q-biotype of B. tabaci in Mi-bearing commercial tomato varieties, which
is greater than that previously reported for the B-biotype.