Combining ability for beet armyworm, Spodoptera exigua, resistance and horticultural traits of selected Lycopersicon pennellii‐derived inbred backcross lines of tomato

Abstract

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[

Trichomes of Lycopersicon spp. and their effect on Myzus persicae (Sulzer) (Hemiptera: Aphididae)

“…The close phylogenetic relationship between L. pennellii and L. hirsutum suggests that the findings of Lemke & Mutschler (1984) and Goffreda & Mutschler (1989) applies to other studies on the inheritance of resistance. However, the transfer of resistance traits to L. esculentum, whilst maintaining fruit quality, may not be straight forward, due to an apparent linkage between resistance and fruit characteristics (Hartman & St Clair 1999).…”

Distortion of trichome morphology by the hairless mutation of tomato affects leaf surface chemistry

“…Among the broad classes of tomato leaf compounds known to deter insect herbivores are acyl sugars, methyl ketones, terpenes, and alkaloids. Acyl sugars exuded by type IV trichomes of S. pennellii confer resistance to numerous insect pests of tomato, including aphids ( Macrosiphum euphorbiae and Myzus persicae ), whitefly ( Bemisia argentifolii ), leaf miners ( Liriomyza trifolii ), tomato fruitworm ( Helicoverpa zea ), and beet armyworm ( Spodoptera exigua ) (Gentile and Stoner, 1968; Goffreda et al , 1990; Rodriguez et al , 1993; Juvik et al , 1994; Blauth et al , 1998; Hartman and St Clair, 1999). Type VI trichomes on certain accessions of S .…”

Trichome characteristics of F1 Lycopersicon esculentum × L. cheesmanii f. minor and L. esculentum × L. pennellii hybrids and effects on Myzus persicae

“…This relationship is likely to be due to the acylsugars found in the exudates of type IV trichomes on L. pennellii (Liedi et al, 1995). L. esculentum × L. pennellii hybrids have been shown to be resistant to Liriomyza trifolii (Burgess) (Erb et al, 1993), Trialeurodes vaporariorum (Westwood) (Erb et al, 1994), Helicoverpa zea (Boddie), Spodoptera exigua (Hubner) (Hartman & St Clair, 1999) and Macrosiphum euphorbiae (Thomas) (Goffreda et al, 1989). Goffreda et al (1988) found that fewer M. euphorbiae settled, and that probing and feeding were reduced, on L. esculentum × L. pennellii hybrids when compared to L. esculentum.…”