Three elite tomato (Solanum lycopersicum L., syn. Lycopersicon esculentum Mill.) breeding lines (TOM‐687, TOM‐688, TOM‐689) with high foliar acylsugar (AS) contents were obtained, and used along with two low‐AS lines (TOM‐690, TOM‐684) in hybrid combinations, to obtain six hybrids between one low‐AS line × one high‐AS line (= hybrids with intermediate AS levels), one hybrid between two high‐AS lines (= high‐AS hybrid), and one hybrid between two low‐AS lines (= low‐AS hybrid). These genotypes were tested for resistance to three different tomato pests (spider mites [Tetranychus urticae Koch], silverleaf whitefly [Bemisia argentifolii Bellows & Perring], and the South American tomato pinworm [Tuta absoluta (Meyrick)]) along with hybrid TEX‐154 (low‐AS) and/or Solanum pennellii Correll ‘LA‐716’ (high‐AS wild accession). In all three instances, high‐AS genotypes showed higher levels of pest resistance than low‐AS genotypes. Hybrids with intermediate AS levels showed resistances that were just as high as those of high‐AS genotypes for Bemisia argentifolii and Tuta absoluta, and nearly as good as those for Tetranychus urticae. Acylsugars were confirmed as being a major component of the high levels of pest resistances found in S. pennellii—a component that was successfully introgressed into elite tomato breeding lines. Acylsugar‐mediated pest resistance is effective against a broad spectrum of tomato pests. Because high‐AS breeding lines are scarce, the deployment of hybrids between high‐AS line × low‐AS line would be a quick, viable alternative to obtain commercial pest‐resistant hybrids.

We examined the resistance of improved tomato strains rich in 2-tridecanone (2-TD), zingiberene (ZGB) and acyl sugars (AA) to the tomato moth, Tuta absoluta. We also studied whether selection for strains with higher densities of glandular trichomes, and thus presumably strains with higher concentrations of 2-tridecanone, was effective in promoting greater resistance to the moth. The TOM-584 and TOM-679 strains were used as susceptible controls, which have normal concentrations of the three allelochemicals. The improved strain TOM-687, which has a high AA content, has a widely documented resistance and was used as a standard resistant strain. The wild strain PI134417, which is resistant by means of its high 2-TD content, was also used as a standard resistant strain. The experiment was installed in a greenhouse with a completely randomized design. The wild strain PI 134417 was confirmed as being highly resistant. TOM-622 (rich in 2-TD), ZGB-703 (rich in ZGB), and TOM-687 (rich in AA) showed significant reductions in the oviposition rate of the tomato moth, damage to the plants, injury to the leaflets, and the percentage of leaflets attacked in comparison with the control strains (TOM-584 and TOM-679). The levels of resistance to the moth for the TOM-622, ZGB-703, and TOM-687 strains were similar. In general, the genotypes with higher densities of glandular trichomes had greater resistance than the susceptible controls, with the strain BPX-367D-238-02 being particularly notable in its resistance.Index terms: Solanum lycopersicum, genotypes, breeding, indirect selection. RESUMOComparou-se a efetividade de linhagens melhoradas de tomateiro, ricas em 2-tridecanona (2-TD), zingibereno (ZGB) e acilaçúcares (AA), em relação aos níveis de resistência à traça-do-tomateiro Tuta absoluta. Verificaram-se, também, se linhagens selecionadas para maiores densidades de tricomas glandulares, presumivelmente com maiores níveis de 2-tridecanona, são efetivas em promover maior resistência à traça. Como testemunhas suscetíveis foram utilizadas as linhagens TOM-584 e TOM-679, com nível normal dos três aleloquímicos. A linhagem melhorada TOM-687 (com alto teor de AA) foi utilizada como linhagem resistente padrão, por ter sua resistência amplamente documentada, juntamente com o também resistente acesso selvagem PI134417 (com alto teor de 2-TD). O experimento foi instalado em casa de vegetação, em delineamento inteiramente casualizado. O acesso selvagem PI 134417 confirmou-se como altamente resistente. TOM-622 (rica em 2-TD), ZGB-703 (rica em ZGB) e TOM-687 apresentaram diminuições significativas na ovoposição da traça-do-tomateiro, bem como no dano geral na planta, lesão nos folíolos e porcentagem de folíolos atacados, comparadas às testemunhas TOM-584 e TOM-679. Os níveis de resistência à traça em TOM-622, ZGB-703 e TOM-687 foram similares entre si. Em geral, os genótipos selecionados com maiores densidades de tricomas glandulares apresentaram níveis de resistência também superiores aos das testemunhas suscetíveis, destacando en...

Zingiberene (ZGB) and acylsugars (AS) are allelochemicals responsible for high levels of arthropod resistance found in Solanum habrochaites (= Lycopersicon hirsutum) var. hirsutum 'PI 127826' and S. (= L.) pennelli 'LA 716', respectively. These accessions were used to develop commercial lines with good levels of pest resistance. The objective of the present work was to assess the ZGB and AS contents and the levels of resistance to Tuta absoluta in tomato hybrids between high ZGB 9 high AS lines, as compared with their parental lines and with commercial checks. High AS homozygous lines [TOM-688 and TOM-689, both originated from the interspecific cross S. lycopersicum (= L. esculentum) 9 S. pennelli], high ZGB homozygous lines (ZGB-703 and ZGB-704, both derived from the interspecific cross S. lycopersicum 9 S. habrochaites var. hirsutum), double heterozygotes for both ZGB and AS, single heterozygotes for ZGB, and single heterozygotes for AS were assessed for AS and ZGB contents. Low-ZGB low-AS checks 'Débora Max' and 'TOM-684' were used, as well as checks with high ZGB (PI 127826) and high AS (LA 716). The genotypes were submitted to infestation with South American tomato pinworm adults in a screenhouse, and oviposition counts were taken 10 days after the initial infestation date. Plants were scored for overall plant damage and percent leaflets attacked up to the 38th day after infestation. Genotypes heterozygous for ZGB or AS showed allelochemical contents intermediate to those of their high and low content parents, indicating incompletely dominant gene action for contents of each of the allelochemicals. There were no significant differences in T. absoluta oviposition between high-AS homozygous genotypes, high-ZGB homozygotes, single heterozygotes for AS, single heterozygotes for ZGB and double heterozygotes for ZGB and AS, but all these genotypes showed egg counts significantly lower than the low-ZGB low-AS checks. Feeding damage of T. absoluta was higher in the low-ZGB low-AS checks than in any other ZGB-rich or AS-rich tomato genotype. Relative to ZGB or AS single heterozygotes, the heterozygotes for both ZGB and AS showed higher levels of resistance to the insect, as measured by overall plant damage, indicating a synergic effect of the allelochemicals on resistance.

O objetivo deste trabalho foi comparar os graus de resistência à mosca-branca (Bemisia argentifolii) e ao ácaro-rajado (Tetranychus urticae) de híbridos de tomateiro resultantes do cruzamento entre linhagens com alto teor de zingibereno (ZGB) e linhagens com alto teor de acilaçúcar (AA), em contraste com as linhagens parentais e testemunhas comerciais. Foram avaliadas linhagens com altos teores de AA, linhagens com alto teor de ZGB, híbridos duplos heterozigotos ZGB+AA, híbridos heterozigotos para ZGB e híbridos heterozigotos para AA. Os acessos selvagens PI-127826 e LA-716 foram utilizados como testemunhas para alto teor de ZGB e AA, respectivamente, e os genótipos Débora Max e TOM-684 foram utilizados como testemunhas para baixo teor de ambos os aleloquímicos. Os genótipos foram submetidos ao teste de resistência à mosca-branca e ao teste de repelência ao ácaro. Os genótipos duplos heterozigotos apresentaram graus de resistência à mosca-branca superiores aos das testemunhas comerciais e inferiores aos das linhagens com alto ZGB ou com alto AA. Os genótipos duplos heterozigotos apresentaram maior repelência ao ácaro, em relação às testemunhas comerciais, e repelência semelhante à das linhagens com alto ZGB ou com alto AA. Não foi observado efeito sinérgico entre ZGB e AA nos genótipos duplos heterozigotos quanto à resistência à mosca-branca e repelência ao ácaro.

Little is known about the commercial potential of mini-tomato hybrids obtained from one dwarf parent. Thus, our objective was to evaluate the agronomic performance of mini-tomato hybrids obtained by crossing a dwarf line (A) with normal lines with indeterminate (I), determinate (D) and semi-determinate (SD) growth habits. The experiment was conducted in a greenhouse at the Estação Experimental de Hortaliças at the Universidade Federal de Uberlândia-UFU in Monte Carmelo, Brazil. The experiment was completely randomized with 17 treatments and four repetitions. The genetic material consisted of 16 experimental mini-tomato hybrids from the tomato germplasm bank at UFU, and a commercial hybrid (Mascot) as a control. The following variables were used to evaluate agronomic performance: fruit weight (g); number of fruits plant ; stem diameter (mm); distance between first bunch and soil (cm); internode length (cm) and total soluble solids (°Brix). The growth habit of the parents influenced the performance of the hybrids. In general, the mini-tomato hybrids from dwarf lines differed from the control with respect to all variables except number of fruits plant -1 , number of fruits bunch -1 and stem diameter. On average, hybrids from dwarf lines showed higher productivity (20%), shorter internodes (11%) and a shorter distance between the first bunch and the ground (30%), relative to the control. Using dwarf lines to obtain mini-tomato hybrids was shown to be viable since the hybrids demonstrated better agronomic performance.