Insect resistant accessions of wild Lycopersicon species were identified long ago, yet insect resistance has not been successfully introgressed into tomato cultivars. The effectiveness of the inbred backcross method for introgressing resistance to beet armyworm (Spodoptera exigua Hübner), tomato fruitworm (Helicoverpa zea Boddie), and potato aphid (Macrosiphum euphorbiae Thomas) from the resistant Lycopersicon pennellii (Corr) D'Arcy acc. ‘LA 716’ into Lycopersicon esculentum Mill. ‘Peto 95’ was examined. Inbred backcross populations at two backcross levels (BC2 and BC3) were developed and tested at two levels of selfing over 2 yr (i.e., S3 in 1994 and S4 in 1995) for resistance in no‐choice egg‐inoculated field assays to beet armyworm and tomato fruitworm and to natural populations of potato aphid. Variation among inbred backcross lines (IBL) in the amount of fruit damage from beet armyworm and tomato fruitworm and the proportion of potato aphid infested plants was observed. Significant line × year interactions suggest that genotype × environment effects may be important to beet armyworm and tomato fruitworm resistance. Differences between observed and predicted gain in beet armyworm and tomato fruitworm resistance of post hoc selected IBL were found, which might be attributed to underestimation of genotype × environment effects, or to non‐additive genetic effects. Large genetic correlations (r2g) between reduced fruit damage and later maturity, lower fruit yield, and smaller fruit mass were estimated. The inbred backcross method was used to successfully introgress insect resistance from L. esculentum to cultivated tomato, but the development of commercially acceptable cultivars will require further cycles of breeding.

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Crop growth and damage parameters (plant growth and yield, root damage and nematode population densities), believed to be associated with resistance of Musa genotypes to nematodes under field conditions, were evaluated in a field trial of 24 Musa genotypes inoculated at planting with a combination of Radopholus similis and Helicotylenchus multicinctus with the objective to identify parameters with strong association with nematode resistance and high heritability. Correlation and path analysis of the association between plant growth, yield, root damage and nematode population densities showed a strong negative association between percentage dead roots, percentage root necrosis, R. similis and H. multicinctus population densities and yield. The strongest negative association was observed between percentage dead roots and yield. Broad-sense genotype heritability estimates demonstrated that heritability estimates for percentage dead roots, number of large lesions and nematode population density were most affected by inoculation with nematodes. These results indicate therefore that effective selection for nematode resistance under field conditions could be obtained by using an index, that includes percentage dead roots, the number of large lesions, and nematode population density.

Ten selected inbred backcross lines "IBL#\ from a Lycopersicon escu! lentum cv[ {Peto 84| × Lycopersicon pennellii IBL population\ with resistance to beet armyworm "BAW#\ Spodoptera exi`ua\ higher fruit mass and fruit yield\ were crossed with eight elite cultivated L[ escu! lentum inbred lines in a Design II mating design[ Three elite inbreds were also crossed to {Peto 84|\ the IBL recurrent parent\ as a control for combining ability[ Field plots of all resulting F 0 progenies and control cultivars were inoculated with BAW eggs and evaluated for resistance to BAW\ fruit mass\ fruit yield\ vine size and maturity at three _eld locations[ Reductions in fruit damage by BAW were found in four of the 09 IBL F 0 progenies[ Signi_cant male and female general combining ability "GCA# estimates for BAW resistance were observed\ but signi_cant speci_c combining ability for BAW resistance was not detected[ The fruit mass of F 0 hybrids was signi_cantly lower than large!fruited controls\ but was not signi_cantly di}erent from elite inbred by {Peto 84| F 0 hybrids[ Selection based on inbred performance identi_ed IBL with positive GCA for BAW resistance and yields in Design II hybrids[ BAW resistance in the 09 selected IBL and IBL! derived F 0 progeny was associated with two undesirable traits\ later maturity and larger vine size[ Index selection of IBL was more e}ective at identifying IBL with positive GCA for fruit mass and fruit yield than GCA for BAW resistance[

Five inbred backcross lines "IBL# were selected for higher relative expression of insecticidal acyl sugars "rank average# from an inbred backcross population derived from the cross Lycopersicon esculentum cultivar {Peto 84| × Lycopersicon pennellii accession LA 605[ These _ve BC 1 S 4 IBLs were crossed in a partial diallel design "Method II#\ and their self and F 0 progeny and three control cultivars were tested at two California _eld locations in 0885[ Counts of potato aphids\ Mac! rosiphum euphorbiae Thomas\ on leaves\ as a measure of plant infes! tation\ revealed signi_cant general combining ability "GCA# for lower aphid numbers with IBL33 and IBL48^the F 0 hybrid IBL33 × IBL48 had signi_cantly fewer aphids per lea~et than the susceptible cultivar {Alta|[ GCA for acyl sugars was associated with IBL48 only[ Of all the IBL and IBL × IBL F 0 hybrids\ only IBL48 produced signi_cant levels of acyl sugars[ Signi_cant within IBL48 variation for acyl sugars was observed\ but not for aphid resistance[ Our results suggest that factors other than acyl sugars contributed to L[ pennellii!derived aphid resist! ance in IBL × IBL F 0 hybrids and IBL that do not produce signi_cant amounts of acyl sugars[ IBL48 and IBL33 may be useful for breeding for aphid resistance in cultivated tomato[