Insect resistance in Lycopersicon hirsutum LA2329 -current status

The core collections of two tomato wild relatives, Lycopersicon hirsutum and L. pennellii, were screened in the open field for resistance to aphids. Nearly all accessions of L. pennellii were resistant to aphids. For the accessions of L. hirsutum, some accessions were very susceptible, some were intermediate and others were extremely resistant. When these lines were being screened for aphid resistance, a line of L. hirsutum, LA2329, was discovered that possessed resistance to leaf miner (Liriomyza spp.). Subsequent attempts to evaluate spidermite and leafminer resistance in this line and in hybrids of LA2329 with cultivated tomato indicated that resistance was dominant and relatively easy to transfer to the hybrids. This is an unusual result since a high level of resistance is not commonly uncovered in early generations of tomato interspecific hybrids. Recovering resistance in early generation backcross populations is equally unusual. In order to study mechanism of resistance, we have conducted spider mite bioassays on a range hybrids of interspecific origin. Progress, including our most recent results with the second backcross gene ration is reviewed.