ABSTRACT Allelochemicals and Mi, nematode‑resistant gene, are found in wild tomato species and can provide resistance to insect pests. The aim of this study was to check the resistance of tomato (Solanum lycopersicum L.) genotypes with different foliar allelochemical contents (acylsugar and/or zingiberene) associated with and not associated with the Mi gene against the whitefly (Bemisia tabaci biotype B). Fifteen tomato genotypes were tested for resistance against whitefly (Santa Clara, TOM‑695, TOM‑556, TOM‑584, TOM‑684, TOM‑687, TOM‑688, TOM‑759, TOM‑760, ZGB‑703, ZGB‑704, TOM‑778, TOM‑779, TOM‑780, and PI‑127826). Genotypes with high acylsugar (AS) (TOM‑687 and TOM‑688) as well as those with high zingiberene (ZGB) contents (ZGB‑703 and ZGB‑704) had lower oviposition and a lower number of nymphs when compared with genotypes with low AS and ZGB contents and without the Mi gene (Santa Clara, TOM‑ 695, TOM‑556, and TOM‑584). The genotypes carrying the Mi gene, associated with low allelochemical contents, were less preferred for whitefly oviposition compared with susceptible genotypes with low AS and ZGB contents and without the Mi gene. When both the AS and ZGB allelochemicals were present in the same genotypes (TOM‑778, TOM‑779, and TOM-780), they showed a synergistic effect; the number of whitefly eggs and nymphs decreased in genotypes with high AS and ZGB compared with genotypes that had only one of these allelochemicals. However, the number of whitefly eggs and nymphs of genotypes with high AS and ZGB contents, individually or combined, was less than for genotypes carrying the Mi gene. These results indicate that allelochemicals are more effective than the Mi gene to provide resistance to whitefly.

Resumo: O objetivo deste trabalho foi verificar a resistência à lagarta Helicoverpa armigera (Lepidoptera: Noctuidae), em genótipos de tomateiro obtidos do cruzamento interespecífico de Solanum lycopersicum x S. galapagense, e a associação dessa resistência com a densidade de tricomas glandulares do tipo IV. Genótipos da população F2, derivada do cruzamento S. lycopersicum TOM-684 x S. galapagense LA-1401, selecionados quanto à baixa e à alta densidade de tricomas glandulares, respectivamente, foram submetidos a dois testes de resistência à lagarta H. armigera em laboratório, um de antibiose e outro de antixenose. Os genótipos da população F2, com alta densidade de tricomas glandulares do tipo IV (BPX-486-17, BPX-486-62, BPX-486-10, BPX-486-46 e BPX-486-08), apresentam maiores níveis de resistência, tanto por antibiose quanto por antixenose, do que os genótipos com baixa densidade de tricomas glandulares (BPX-486-313 e BPX-486-383) e do que as testemunhas 'Santa Clara' e TOM-684. Os níveis de resistência foram menores do que os do genitor silvestre LA-1401.

Abstract: The objective of this work was to verify the resistance to the Helicoverpa armigera (Lepidoptera: Noctuidae) caterpillar by tomato genotypes obtained from interspecific crossing of Solanum lycopersicum x S. galapagense, and the association of this resistence with the density of type IV glandular trichomes. Genotypes of the F2 population, obtained from the crossing of S. lycopersicum TOM-684 x S. galapagense LA-1401, selected for low and high densities of glandular trichomes, respectively, were subjected to two laboratory resistance tests, one for antibiosis and other for antixenosis. Genotypes of the F2 population, with high density of type IV glandular trichomes (BPX-486-17, BPX-486-62, BPX-486-10, BPX-486-46 and BPX-486-08), showed higher resistance levels, both by antibiosis and antixenosis, than the genotypes with low-density glandular trichomes (BPX-486-313 and BPX-486-383) and the witnesses 'Santa Clara' and TOM-684. Resistance levels were lower than those of the wild parent LA-1401.

No Brasil, o tomate é cultivado em praticamente todas as regiões, embora seu rendimento seja reduzido por pragas e doenças. A mosca-branca, comumente presente, causa danos diretos e indiretos, devido à transmissão de geminiviros. O objetivo do presente trabalho foi comparar o grau de resistência à mosca branca de linhagens de tomateiro ricas em acilaçúcares (AA), zingibereno (ZGB) e 2-tridecanona (2-TD) e verificar se a seleção de linhagens com base em tricomas glandulares é efetiva no sentido de promover níveis satisfatórios de resistência. Essas linhagens foram obtidas através de retrocruzamentos em tomateiro Solanum lycopersicum, a partir do cruzamento interespecífico S. lycopersicum x S. habrochaites var. glabratum 'PI 1344171'. Linhagens ricas em AA , ZGB e 2-TD foram testadas para níveis de resistência. Duas linhagens de tomateiro (TOM-584 e TOM-679), com nível normal de AA, e o acesso selvagem (PI 134417), alto teor de 2-TD, foram utilizados como testemunhas. TOM-687, ZGB-703 e TOM-622 mostraram diminuições na ovoposição e na contagem de ninfas, quando comparados com os controles TOM-584 e TOM-679. As linhagens ricas nos aleloquímicos mostraram níveis de resistência à praga, relativamente aos controles, e não deferiram significativamente entre si. Os resultados mostram que linhagens ricas em AA, ZGB e 2-TD são eficazes alternativas de seleção indireta para criação de resistência a Bemisia argentifolii. As linhagens selecionadas para maior densidade de tricomas, exceto BPX-365F-751-05-01-03, apresentaram números médios de ninfas inferiores ao das testemunhas suscetíveis, indicando que a seleção para maior número de tricomas glandulares foi efetiva no sentido de promover aumento dos níveis de resistência à mosca-branca.

In Brazil, the tomato is cultivated in almost all geographic regions even though its yield is significantly reduced by pests and diseases. Among these pests and diseases, whitefly is a major problem that causes direct and indirect damage due to its role in transmission of geminiviruses. The aim of the present study was to compare the degree of resistance to the silverleaf whitefly of tomato plant lines rich in acyl sugars (AS), zingiberene (ZGB), and 2-tridecanone (2-TD) and to establish whether selection for strains with higher densities of glandular trichomes promotes sufficient resistance to this insect pest. The investigated lines were developed by performing back-crossings in tomato (Solanum lycopersicum) from the interspecific crossing of S. lycopersicum x S. habrochaites var. glabratum 'PI 134417'. Lines rich in AS, ZGB, and 2-TD were tested for their levels of resistance to B. tabaci biotype B. Two tomato plant lines (TOM-584 and TOM-679) with normal AS levels and one wild specimen (PI 134417) with high 2-TD content were used as controls. TOM-687, ZGB-703, and TOM-622 were less preferred by B. tabaci for oviposition, and nymphs exhibited a poorer survival rate on those plant lines than on the susceptible controls, TOM-584 and TOM-679. Allelochemical-rich lines exhibited pest resistance, whereas the controls did not, and the allelochemical-rich lines did not differ significantly from each other in the level of resistance. The results show that the development of tomato plant lines rich in 2-TD, ZGB and AS is an effective option for indirect selection for resistance to B. tabaci biotype B. All lines selected based on high trichome density except for BPX-365F-751-05-01-03 exhibited fewer nymphs than the susceptible controls, indicating that selection for more glandular trichomes was generally effective in promoting increased resistance to the silverleaf white flay.

Comparou-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 entre eles o tratamento BPX-367D-238-02.

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.

Objetivou-se avaliar o potencial de silagens de ramas de diferentes clones de batata-doce para alimentação animal. O trabalho foi realizado na Fazenda Forquilha localizada no Distrito de Batatal, município de Diamantina MG, no período de 23/12/2007 a 23/06/2008. O experimento foi conduzido no esquema de parcelas subdivididas em delineamento de blocos completos casualizados. Foram avaliadas a produtividade de matéria verde e matéria seca das ramas e a composição químico-bromatológica, além do perfil fermentativo de suas silagens, em três idades de colheita (120, 150 e 180 dias), em oito clones de batata doce. A produtividade de matéria seca não variou com a época de colheita das ramas, obtendo-se média de 6,01t ha-1. Os teores de matéria seca nas ramas aumentaram com o ciclo da cultura, verificando-se teores médios de 11,94; 12,16 e 19,62%, aos 120, 150 e 180 dias após o corte, respectivamente. As silagens das ramas de batata-doce apresentaram altos teores protéicos e energéticos e adequado perfil fermentativo, portanto, apresentam potencial para utilização na alimentação animal, independentemente dos clones.

The objective was to evaluate the potential of silage derived from different clones of sweet potato for animal feed. The study was conducted at Forquilha Farm located in Batatal district, MG Diamantina in the period from 23/12/2007 to 23/06/2008. The experiment was conducted in split plot design in a randomized complete block. It was evaluated the green and dry matter yield, the chemical composition and the fermentative profile of silage harvested on three dates (days 120, 150 and 180), of eight clones of sweet potato. The dry matter yield did not vary according to the harvest time of the branches, resulting in an average of 6.01t ha-1. The dry matter content in the stems increased with the growth cycle, and there are average levels of 11.94, 12.16 and 19.62% on days 120, 150 and 180 after cutting, respectively. The raw potato silage showed high protein content and adequate energy fermentation and therefore, potential for use in animal feed, regardless of clones.