The leafhopper species Empoasca fabae and Empoasca kraemeri are the most important insect pests on field bean in Ontario Canada and in Colombia, South America, respectively. A white-seeded resistant line developed at CIAT, EMP419, has been crossed with a highly susceptible Dutch brown bean, Berna. A population of 108 recombinant inbred lines (RILs) was developed. The lines were evaluated for resistance to leafhoppers in the field at two locations in Ontario and in the Cauca Valley in Colombia under natural infestation of E. fabae and E. kraemeri for Ontario and Colombia, respectively. DNA from resistant and susceptible lines was used in a bulked segregant analysis that employed 203 RAPD markers. Several of the identified RAPD markers cosegregated with the resistance trait in the RILs. Additional RAPDs, RFLPs and microsatellite markers have been used to construct a genetic linkage map. Morphological traits were also examined. Indeterminate growth habit was associated with higher leafhopper resistance scores and in Colombia, white-seeded inbred lines had higher levels of resistance. The resistance mechanism was investigated. Higher numbers of nymphs were found on the Berna cultivar and the susceptible RILs than on EMP419 and the resistant inbred lines. This suggests the presence of an antixenosis type of resistance in this population.
Species 1: Homoptera Cicadellidae Empoasca fabae (potato leafhopper)
Species 2: Homoptera Cicadellidae Empoasca kraemeri
Keywords: Phaseolus vulgaris, molecular markers
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA