ABSTRACT The use of pre-emergent herbicides is important for the current agricultural production systems that present weeds resistant to herbicides. Considering the complexity of using these products, the objective of this work was to evaluate their selectivity and residual weed control in soybean crops and their effect on the weeds Amaranthus hybridus, Bidens pilosa, Digitaria insularis, Eleusine indica, and Euphorbia heterophylla. The herbicide selectivity experiments were conducted under field conditions in the 2017/18 and 2019/20 crop seasons and the herbicide efficacy experiments were conducted under greenhouse conditions. The herbicides s-metolachlor and flumioxazin can be applied on day of the soybean sowing without causing significant grain yield losses. Diclosulam and sulfentrazone are safe for soybean crops when applied at least 14 days before sowing. The herbicides used proved to be good options for weed management systems for soybean crops; flumioxazin and sulfentrazone were the herbicides that promoted the best control for all evaluated weed species and ensured a residual effect of at least 30 days.

ABSTRACT Whiteflies (Bemisia tabaci) are a serious threat to tomato (Solanum lycopersicum) yield and production since all varieties are highly susceptible to this insect. The wild tomato Solanum pennellii shows resistance towards whiteflies infestation due the high contents of acylsugars presents in its leaflets, which is not observed in S. lycopersicum. Thus, plants from the F2BC2 population derived from the cross between the cultivar S. lycopersicum ‘Redenção’ and S. pennellii (accession LA-716) were selected for acylsugars levels and evaluated for resistance to whitefly and fumagine, a saprophyte fungus from genus Capnodium (sooty mold) that grows on leaves using whiteflies excretion. Biological behavior of B. tabaci was significantly influenced by the levels of acylsugars on the leaflets of the different genotypes. Solanum pennellii and the genotypes with higher acylsugars contents exhibited the lowest whitefly oviposition preference, number of nymphs, exuviae and adult survival. Also, the percentage of leaf coverage with fumagine was significantly reduced on leaves of the S. pennellii and the genotypes with higher acylsugars. Thus, it confirms that the use of S. pennellii LA-716 enabled the introgression of genes to increase the degrees of resistance in the F2BC2 genotypes. Finally, the results presented suggest that the genotypes RVTA-2010-31-177pl#39, RVTA-2010-31-319pl#214 and RVTA-2010-83-347pl#257 can be used as potential sources of genes for resistance to B. tabaci in tomato breeding programs.

RESUMO O presente trabalho teve como objetivo avaliar o pegamento de enxertia de tomateiro, em diferentes espécies de solanáceas e por diferentes métodos de enxertia. Foram produzidas para enxerto mudas de tomateiro da cultivar Santa Cruz Kada®. O delineamento experimental utilizado foi o inteiramente casualizado, com os tratamentos arranjados em esquema fatorial 9 x 2, avaliando-se como porta-enxerto: os acessos de minitomate 0224-53, RVTC 57, RVTC 20 e 6889-50 (Solanum lycopersicum L); as espécies silvestres de tomateiro Solanum habrochaites var hirsutum ‘PI-127826’ e Solanum pennellii ‘LA716’; duas outras espécies Solanum, cubiu (Solanum sessiliflorum) e fisales (Physalis peruviana); e o tomateiro cultivar Santa Cruz Kada® como testemunha (auto-enxertia), e avaliados dois métodos de enxertia: fenda cheia; e encostia. Aos quinze dias após a enxertia, as plantas foram avaliadas quanto ao: índice de pegamento de enxertia; comprimento de raiz; altura das plantas; número de folhas; área foliar; massa seca das raízes, do caule e das folhas; e relação massa seca da parte aérea/massa seca das raízes. Com base nos resultados obtidos, foi possível verificar que o índice de pegamento e o desenvolvimento vegetativo das plantas após a enxertia em tomateiro foi influenciado significativamente pela interação (porta-enxerto x método de enxertia). Dentre os porta-enxertos avaliados, todos podem ser recomendados, exceto o acesso de minitomate 6889-50 (S. lycopersicum L.) e a espécie S. pennellii. Para os porta-enxertos cubiu e fisales recomenda-se a utilização do método de enxertia por fenda cheia, e para os porta-enxertos acesso de (minitomate 0224-53, RVTC 57 e RVTC 20; e espécie S. habrochaites) o método de encostia.

ABSTRACT This paper aimed to assess tomato grafting on different solanaceous species through two grafting methods. Scions were cut from cultivar Santa Cruz Kada seedlings. A fully randomized experimental design was carried out with treatments in a 9 x 2 factorial scheme. As rootstocks, four accessions of mini-tomatoes (0224-53, RVTC 57, RVTC 20 and 6889-50 - Solanum lycopersicum L); two species of wild tomato (Solanum habrochaites var hirsutum ‘PI-127826’ and Solanum pennellii ‘LA716’); other two tomato species [Solanum, cocona (Solanum sessiliflorum) and physalis (Physalis peruviana)] and a control with cultivar Santa Cruz Kada (auto-graft) rootstocks were used. In addition, two grafting methods were evaluated full cleft and approach graft. Fifteen days after grafting, plants were assessed for graft-take percentage; root length; plant height; leaf number; foliar area; root, stem and leaf dry matter; and ratio between shoot and root dry matter. Based on the results, we may state rootstock and grafting interaction had effect on both graft -take rate and plant development. Overall, the studied plants should be recommended as rootstock, except for 6889-50 mini-tomato (S. lycopersicum L.) and S. pennellii. Full cleft grafting was most suitable for cocona and physalis, while the approach method showed better results for the mini-tomato accessions 0224-53, RVTC 57 and RVTC 20, as well as for S. habrochaites.